Imported from /home/lorry/working-area/delta_ntp/ntp-dev-4.2.7p482.tar.gz.ntp-dev-4.2.7p482

1 files changed, 3987 insertions, 0 deletions

diff --git a/ntpd/ntp_crypto.c b/ntpd/ntp_crypto.c
new file mode 100644
index 0000000..e66d5c7
--- /dev/null
+++ b/ntpd/ntp_crypto.c
@@ -0,0 +1,3987 @@
+/*
+ * ntp_crypto.c - NTP version 4 public key routines
+ */
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#ifdef AUTOKEY
+#include <stdio.h>
+#include <stdlib.h>	/* strtoul */
+#include <sys/types.h>
+#include <sys/param.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "ntpd.h"
+#include "ntp_stdlib.h"
+#include "ntp_unixtime.h"
+#include "ntp_string.h"
+#include "ntp_random.h"
+#include "ntp_assert.h"
+#include "ntp_calendar.h"
+#include "ntp_leapsec.h"
+
+#include "openssl/asn1_mac.h"
+#include "openssl/bn.h"
+#include "openssl/err.h"
+#include "openssl/evp.h"
+#include "openssl/pem.h"
+#include "openssl/rand.h"
+#include "openssl/x509v3.h"
+
+#ifdef KERNEL_PLL
+#include "ntp_syscall.h"
+#endif /* KERNEL_PLL */
+
+/*
+ * calcomp - compare two calendar structures, ignoring yearday and weekday; like strcmp
+ * No, it's not a plotter.  If you don't understand that, you're too young.
+ */
+static int calcomp(struct calendar *pjd1, struct calendar *pjd2)
+{
+	int32_t diff;	/* large enough to hold the signed difference between two uint16_t values */
+
+	diff = pjd1->year - pjd2->year;
+	if (diff < 0) return -1; else if (diff > 0) return 1;
+	/* same year; compare months */
+	diff = pjd1->month - pjd2->month;
+	if (diff < 0) return -1; else if (diff > 0) return 1;
+	/* same year and month; compare monthday */
+	diff = pjd1->monthday - pjd2->monthday;
+	if (diff < 0) return -1; else if (diff > 0) return 1;
+	/* same year and month and monthday; compare time */
+	diff = pjd1->hour - pjd2->hour;
+	if (diff < 0) return -1; else if (diff > 0) return 1;
+	diff = pjd1->minute - pjd2->minute;
+	if (diff < 0) return -1; else if (diff > 0) return 1;
+	diff = pjd1->second - pjd2->second;
+	if (diff < 0) return -1; else if (diff > 0) return 1;
+	/* identical */
+	return 0;
+}
+
+/*
+ * Extension field message format
+ *
+ * These are always signed and saved before sending in network byte
+ * order. They must be converted to and from host byte order for
+ * processing.
+ *
+ * +-------+-------+
+ * |   op  |  len  | <- extension pointer
+ * +-------+-------+
+ * |    associd    |
+ * +---------------+
+ * |   timestamp   | <- value pointer
+ * +---------------+
+ * |   filestamp   |
+ * +---------------+
+ * |   value len   |
+ * +---------------+
+ * |               |
+ * =     value     =
+ * |               |
+ * +---------------+
+ * | signature len |
+ * +---------------+
+ * |               |
+ * =   signature   =
+ * |               |
+ * +---------------+
+ *
+ * The CRYPTO_RESP bit is set to 0 for requests, 1 for responses.
+ * Requests carry the association ID of the receiver; responses carry
+ * the association ID of the sender. Some messages include only the
+ * operation/length and association ID words and so have length 8
+ * octets. Ohers include the value structure and associated value and
+ * signature fields. These messages include the timestamp, filestamp,
+ * value and signature words and so have length at least 24 octets. The
+ * signature and/or value fields can be empty, in which case the
+ * respective length words are zero. An empty value with nonempty
+ * signature is syntactically valid, but semantically questionable.
+ *
+ * The filestamp represents the time when a cryptographic data file such
+ * as a public/private key pair is created. It follows every reference
+ * depending on that file and serves as a means to obsolete earlier data
+ * of the same type. The timestamp represents the time when the
+ * cryptographic data of the message were last signed. Creation of a
+ * cryptographic data file or signing a message can occur only when the
+ * creator or signor is synchronized to an authoritative source and
+ * proventicated to a trusted authority.
+ *
+ * Note there are several conditions required for server trust. First,
+ * the public key on the server certificate must be verified, which can
+ * involve a hike along the certificate trail to a trusted host. Next,
+ * the server trust must be confirmed by one of several identity
+ * schemes. Valid cryptographic values are signed with attached
+ * timestamp and filestamp. Individual packet trust is confirmed
+ * relative to these values by a message digest with keys generated by a
+ * reverse-order pseudorandom hash.
+ *
+ * State decomposition. These flags are lit in the order given. They are
+ * dim only when the association is demobilized.
+ *
+ * CRYPTO_FLAG_ENAB	Lit upon acceptance of a CRYPTO_ASSOC message
+ * CRYPTO_FLAG_CERT	Lit when a self-digned trusted certificate is
+ *			accepted.
+ * CRYPTO_FLAG_VRFY	Lit when identity is confirmed.
+ * CRYPTO_FLAG_PROV	Lit when the first signature is verified.
+ * CRYPTO_FLAG_COOK	Lit when a valid cookie is accepted.
+ * CRYPTO_FLAG_AUTO	Lit when valid autokey values are accepted.
+ * CRYPTO_FLAG_SIGN	Lit when the server signed certificate is
+ *			accepted.
+ * CRYPTO_FLAG_LEAP	Lit when the leapsecond values are accepted.
+ */
+/*
+ * Cryptodefines
+ */
+#define TAI_1972	10	/* initial TAI offset (s) */
+#define MAX_LEAP	100	/* max UTC leapseconds (s) */
+#define VALUE_LEN	(6 * 4) /* min response field length */
+#define YEAR		(60 * 60 * 24 * 365) /* seconds in year */
+
+/*
+ * Global cryptodata in host byte order
+ */
+u_int32	crypto_flags = 0x0;	/* status word */
+int	crypto_nid = KEY_TYPE_MD5; /* digest nid */
+char	*sys_hostname = NULL;
+char	*sys_groupname = NULL;
+static char *host_filename = NULL;	/* host file name */
+static char *ident_filename = NULL;	/* group file name */
+
+/*
+ * Global cryptodata in network byte order
+ */
+struct cert_info *cinfo = NULL;	/* certificate info/value cache */
+struct cert_info *cert_host = NULL; /* host certificate */
+struct pkey_info *pkinfo = NULL; /* key info/value cache */
+struct value hostval;		/* host value */
+struct value pubkey;		/* public key */
+struct value tai_leap;		/* leapseconds values */
+struct pkey_info *iffkey_info = NULL; /* IFF keys */
+struct pkey_info *gqkey_info = NULL; /* GQ keys */
+struct pkey_info *mvkey_info = NULL; /* MV keys */
+
+/*
+ * Private cryptodata in host byte order
+ */
+static char *passwd = NULL;	/* private key password */
+static EVP_PKEY *host_pkey = NULL; /* host key */
+static EVP_PKEY *sign_pkey = NULL; /* sign key */
+static const EVP_MD *sign_digest = NULL; /* sign digest */
+static u_int sign_siglen;	/* sign key length */
+static char *rand_file = NULL;	/* random seed file */
+
+/*
+ * Cryptotypes
+ */
+static	int	crypto_verify	(struct exten *, struct value *,
+				    struct peer *);
+static	int	crypto_encrypt	(struct exten *, struct value *,
+				    keyid_t *);
+static	int	crypto_alice	(struct peer *, struct value *);
+static	int	crypto_alice2	(struct peer *, struct value *);
+static	int	crypto_alice3	(struct peer *, struct value *);
+static	int	crypto_bob	(struct exten *, struct value *);
+static	int	crypto_bob2	(struct exten *, struct value *);
+static	int	crypto_bob3	(struct exten *, struct value *);
+static	int	crypto_iff	(struct exten *, struct peer *);
+static	int	crypto_gq	(struct exten *, struct peer *);
+static	int	crypto_mv	(struct exten *, struct peer *);
+static	int	crypto_send	(struct exten *, struct value *, int);
+static	tstamp_t crypto_time	(void);
+static	void	asn_to_calendar		(ASN1_TIME *, struct calendar*);
+static	struct cert_info *cert_parse (const u_char *, long, tstamp_t);
+static	int	cert_sign	(struct exten *, struct value *);
+static	struct cert_info *cert_install (struct exten *, struct peer *);
+static	int	cert_hike	(struct peer *, struct cert_info *);
+static	void	cert_free	(struct cert_info *);
+static	struct pkey_info *crypto_key (char *, char *, sockaddr_u *);
+static	void	bighash		(BIGNUM *, BIGNUM *);
+static	struct cert_info *crypto_cert (char *);
+
+#ifdef SYS_WINNT
+int
+readlink(char * link, char * file, int len) {
+	return (-1);
+}
+#endif
+
+/*
+ * session_key - generate session key
+ *
+ * This routine generates a session key from the source address,
+ * destination address, key ID and private value. The value of the
+ * session key is the MD5 hash of these values, while the next key ID is
+ * the first four octets of the hash.
+ *
+ * Returns the next key ID or 0 if there is no destination address.
+ */
+keyid_t
+session_key(
+	sockaddr_u *srcadr, 	/* source address */
+	sockaddr_u *dstadr, 	/* destination address */
+	keyid_t	keyno,		/* key ID */
+	keyid_t	private,	/* private value */
+	u_long	lifetime 	/* key lifetime */
+	)
+{
+	EVP_MD_CTX ctx;		/* message digest context */
+	u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
+	keyid_t	keyid;		/* key identifer */
+	u_int32	header[10];	/* data in network byte order */
+	u_int	hdlen, len;
+
+	if (!dstadr)
+		return 0;
+	
+	/*
+	 * Generate the session key and key ID. If the lifetime is
+	 * greater than zero, install the key and call it trusted.
+	 */
+	hdlen = 0;
+	switch(AF(srcadr)) {
+	case AF_INET:
+		header[0] = NSRCADR(srcadr);
+		header[1] = NSRCADR(dstadr);
+		header[2] = htonl(keyno);
+		header[3] = htonl(private);
+		hdlen = 4 * sizeof(u_int32);
+		break;
+
+	case AF_INET6:
+		memcpy(&header[0], PSOCK_ADDR6(srcadr),
+		    sizeof(struct in6_addr));
+		memcpy(&header[4], PSOCK_ADDR6(dstadr),
+		    sizeof(struct in6_addr));
+		header[8] = htonl(keyno);
+		header[9] = htonl(private);
+		hdlen = 10 * sizeof(u_int32);
+		break;
+	}
+	EVP_DigestInit(&ctx, EVP_get_digestbynid(crypto_nid));
+	EVP_DigestUpdate(&ctx, (u_char *)header, hdlen);
+	EVP_DigestFinal(&ctx, dgst, &len);
+	memcpy(&keyid, dgst, 4);
+	keyid = ntohl(keyid);
+	if (lifetime != 0) {
+		MD5auth_setkey(keyno, crypto_nid, dgst, len);
+		authtrust(keyno, lifetime);
+	}
+	DPRINTF(2, ("session_key: %s > %s %08x %08x hash %08x life %lu\n",
+		    stoa(srcadr), stoa(dstadr), keyno,
+		    private, keyid, lifetime));
+
+	return (keyid);
+}
+
+
+/*
+ * make_keylist - generate key list
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ERR	protocol error
+ *
+ * This routine constructs a pseudo-random sequence by repeatedly
+ * hashing the session key starting from a given source address,
+ * destination address, private value and the next key ID of the
+ * preceeding session key. The last entry on the list is saved along
+ * with its sequence number and public signature.
+ */
+int
+make_keylist(
+	struct peer *peer,	/* peer structure pointer */
+	struct interface *dstadr /* interface */
+	)
+{
+	EVP_MD_CTX ctx;		/* signature context */
+	tstamp_t tstamp;	/* NTP timestamp */
+	struct autokey *ap;	/* autokey pointer */
+	struct value *vp;	/* value pointer */
+	keyid_t	keyid = 0;	/* next key ID */
+	keyid_t	cookie;		/* private value */
+	long	lifetime;
+	u_int	len, mpoll;
+	int	i;
+
+	if (!dstadr)
+		return XEVNT_ERR;
+	
+	/*
+	 * Allocate the key list if necessary.
+	 */
+	tstamp = crypto_time();
+	if (peer->keylist == NULL)
+		peer->keylist = emalloc(sizeof(keyid_t) *
+		    NTP_MAXSESSION);
+
+	/*
+	 * Generate an initial key ID which is unique and greater than
+	 * NTP_MAXKEY.
+	 */
+	while (1) {
+		keyid = ntp_random() & 0xffffffff;
+		if (keyid <= NTP_MAXKEY)
+			continue;
+
+		if (authhavekey(keyid))
+			continue;
+		break;
+	}
+
+	/*
+	 * Generate up to NTP_MAXSESSION session keys. Stop if the
+	 * next one would not be unique or not a session key ID or if
+	 * it would expire before the next poll. The private value
+	 * included in the hash is zero if broadcast mode, the peer
+	 * cookie if client mode or the host cookie if symmetric modes.
+	 */
+	mpoll = 1 << min(peer->ppoll, peer->hpoll);
+	lifetime = min(1U << sys_automax, NTP_MAXSESSION * mpoll);
+	if (peer->hmode == MODE_BROADCAST)
+		cookie = 0;
+	else
+		cookie = peer->pcookie;
+	for (i = 0; i < NTP_MAXSESSION; i++) {
+		peer->keylist[i] = keyid;
+		peer->keynumber = i;
+		keyid = session_key(&dstadr->sin, &peer->srcadr, keyid,
+		    cookie, lifetime + mpoll);
+		lifetime -= mpoll;
+		if (auth_havekey(keyid) || keyid <= NTP_MAXKEY ||
+		    lifetime < 0 || tstamp == 0)
+			break;
+	}
+
+	/*
+	 * Save the last session key ID, sequence number and timestamp,
+	 * then sign these values for later retrieval by the clients. Be
+	 * careful not to use invalid key media. Use the public values
+	 * timestamp as filestamp. 
+	 */
+	vp = &peer->sndval;
+	if (vp->ptr == NULL)
+		vp->ptr = emalloc(sizeof(struct autokey));
+	ap = (struct autokey *)vp->ptr;
+	ap->seq = htonl(peer->keynumber);
+	ap->key = htonl(keyid);
+	vp->tstamp = htonl(tstamp);
+	vp->fstamp = hostval.tstamp;
+	vp->vallen = htonl(sizeof(struct autokey));
+	vp->siglen = 0;
+	if (tstamp != 0) {
+		if (vp->sig == NULL)
+			vp->sig = emalloc(sign_siglen);
+		EVP_SignInit(&ctx, sign_digest);
+		EVP_SignUpdate(&ctx, (u_char *)vp, 12);
+		EVP_SignUpdate(&ctx, vp->ptr, sizeof(struct autokey));
+		if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey)) {
+			vp->siglen = htonl(sign_siglen);
+			peer->flags |= FLAG_ASSOC;
+		}
+	}
+#ifdef DEBUG
+	if (debug)
+		printf("make_keys: %d %08x %08x ts %u fs %u poll %d\n",
+		    peer->keynumber, keyid, cookie, ntohl(vp->tstamp),
+		    ntohl(vp->fstamp), peer->hpoll);
+#endif
+	return (XEVNT_OK);
+}
+
+
+/*
+ * crypto_recv - parse extension fields
+ *
+ * This routine is called when the packet has been matched to an
+ * association and passed sanity, format and MAC checks. We believe the
+ * extension field values only if the field has proper format and
+ * length, the timestamp and filestamp are valid and the signature has
+ * valid length and is verified. There are a few cases where some values
+ * are believed even if the signature fails, but only if the proventic
+ * bit is not set.
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ERR	protocol error
+ * XEVNT_LEN	bad field format or length
+ */
+int
+crypto_recv(
+	struct peer *peer,	/* peer structure pointer */
+	struct recvbuf *rbufp	/* packet buffer pointer */
+	)
+{
+	const EVP_MD *dp;	/* message digest algorithm */
+	u_int32	*pkt;		/* receive packet pointer */
+	struct autokey *ap, *bp; /* autokey pointer */
+	struct exten *ep, *fp;	/* extension pointers */
+	struct cert_info *xinfo; /* certificate info pointer */
+	int	has_mac;	/* length of MAC field */
+	int	authlen;	/* offset of MAC field */
+	associd_t associd;	/* association ID */
+	tstamp_t tstamp = 0;	/* timestamp */
+	tstamp_t fstamp = 0;	/* filestamp */
+	u_int	len;		/* extension field length */
+	u_int	code;		/* extension field opcode */
+	u_int	vallen = 0;	/* value length */
+	X509	*cert;		/* X509 certificate */
+	char	statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
+	keyid_t	cookie;		/* crumbles */
+	int	hismode;	/* packet mode */
+	int	rval = XEVNT_OK;
+	const u_char *puch;
+	u_int32 temp32;
+
+	/*
+	 * Initialize. Note that the packet has already been checked for
+	 * valid format and extension field lengths. First extract the
+	 * field length, command code and association ID in host byte
+	 * order. These are used with all commands and modes. Then check
+	 * the version number, which must be 2, and length, which must
+	 * be at least 8 for requests and VALUE_LEN (24) for responses.
+	 * Packets that fail either test sink without a trace. The
+	 * association ID is saved only if nonzero.
+	 */
+	authlen = LEN_PKT_NOMAC;
+	hismode = (int)PKT_MODE((&rbufp->recv_pkt)->li_vn_mode);
+	while ((has_mac = rbufp->recv_length - authlen) > MAX_MAC_LEN) {
+		pkt = (u_int32 *)&rbufp->recv_pkt + authlen / 4;
+		ep = (struct exten *)pkt;
+		code = ntohl(ep->opcode) & 0xffff0000;
+		len = ntohl(ep->opcode) & 0x0000ffff;
+		associd = (associd_t)ntohl(pkt[1]);
+		rval = XEVNT_OK;
+#ifdef DEBUG
+		if (debug)
+			printf(
+			    "crypto_recv: flags 0x%x ext offset %d len %u code 0x%x associd %d\n",
+			    peer->crypto, authlen, len, code >> 16,
+			    associd);
+#endif
+
+		/*
+		 * Check version number and field length. If bad,
+		 * quietly ignore the packet.
+		 */
+		if (((code >> 24) & 0x3f) != CRYPTO_VN || len < 8) {
+			sys_badlength++;
+			code |= CRYPTO_ERROR;
+		}
+
+		if (len >= VALUE_LEN) {
+			tstamp = ntohl(ep->tstamp);
+			fstamp = ntohl(ep->fstamp);
+			vallen = ntohl(ep->vallen);
+		}
+		switch (code) {
+
+		/*
+		 * Install status word, host name, signature scheme and
+		 * association ID. In OpenSSL the signature algorithm is
+		 * bound to the digest algorithm, so the NID completely
+		 * defines the signature scheme. Note the request and
+		 * response are identical, but neither is validated by
+		 * signature. The request is processed here only in
+		 * symmetric modes. The server name field might be
+		 * useful to implement access controls in future.
+		 */
+		case CRYPTO_ASSOC:
+
+			/*
+			 * If our state machine is running when this
+			 * message arrives, the other fellow might have
+			 * restarted. However, this could be an
+			 * intruder, so just clamp the poll interval and
+			 * find out for ourselves. Otherwise, pass the
+			 * extension field to the transmit side.
+			 */
+			if (peer->crypto & CRYPTO_FLAG_CERT) {
+				rval = XEVNT_ERR;
+				break;
+			}
+			if (peer->cmmd) {
+				if (peer->assoc != associd) {
+					rval = XEVNT_ERR;
+					break;
+				}
+			}
+			fp = emalloc(len);
+			memcpy(fp, ep, len);
+			fp->associd = htonl(peer->associd);
+			peer->cmmd = fp;
+			/* fall through */
+
+		case CRYPTO_ASSOC | CRYPTO_RESP:
+
+			/*
+			 * Discard the message if it has already been
+			 * stored or the message has been amputated.
+			 */
+			if (peer->crypto) {
+				if (peer->assoc != associd)
+					rval = XEVNT_ERR;
+				break;
+			}
+			if (vallen == 0 || vallen > MAXHOSTNAME ||
+			    len < VALUE_LEN + vallen) {
+				rval = XEVNT_LEN;
+				break;
+			}
+#ifdef DEBUG
+			if (debug)
+				printf(
+				    "crypto_recv: ident host 0x%x %d server 0x%x %d\n",
+				    crypto_flags, peer->associd, fstamp,
+				    peer->assoc);
+#endif
+			temp32 = crypto_flags & CRYPTO_FLAG_MASK;
+
+			/*
+			 * If the client scheme is PC, the server scheme
+			 * must be PC. The public key and identity are
+			 * presumed valid, so we skip the certificate
+			 * and identity exchanges and move immediately
+			 * to the cookie exchange which confirms the
+			 * server signature.
+			 */
+			if (crypto_flags & CRYPTO_FLAG_PRIV) {
+				if (!(fstamp & CRYPTO_FLAG_PRIV)) {
+					rval = XEVNT_KEY;
+					break;
+				}
+				fstamp |= CRYPTO_FLAG_CERT |
+				    CRYPTO_FLAG_VRFY | CRYPTO_FLAG_SIGN;
+
+			/*
+			 * It is an error if either peer supports
+			 * identity, but the other does not.
+			 */
+			} else if (hismode == MODE_ACTIVE || hismode ==
+			    MODE_PASSIVE) {
+				if ((temp32 && !(fstamp &
+				    CRYPTO_FLAG_MASK)) ||
+				    (!temp32 && (fstamp &
+				    CRYPTO_FLAG_MASK))) {
+					rval = XEVNT_KEY;
+					break;
+				}
+			}
+
+			/*
+			 * Discard the message if the signature digest
+			 * NID is not supported.
+			 */
+			temp32 = (fstamp >> 16) & 0xffff;
+			dp =
+			    (const EVP_MD *)EVP_get_digestbynid(temp32);
+			if (dp == NULL) {
+				rval = XEVNT_MD;
+				break;
+			}
+
+			/*
+			 * Save status word, host name and message
+			 * digest/signature type. If this is from a
+			 * broadcast and the association ID has changed,
+			 * request the autokey values.
+			 */
+			peer->assoc = associd;
+			if (hismode == MODE_SERVER)
+				fstamp |= CRYPTO_FLAG_AUTO;
+			if (!(fstamp & CRYPTO_FLAG_TAI))
+				fstamp |= CRYPTO_FLAG_LEAP;
+			RAND_bytes((u_char *)&peer->hcookie, 4);
+			peer->crypto = fstamp;
+			peer->digest = dp;
+			if (peer->subject != NULL)
+				free(peer->subject);
+			peer->subject = emalloc(vallen + 1);
+			memcpy(peer->subject, ep->pkt, vallen);
+			peer->subject[vallen] = '\0';
+			if (peer->issuer != NULL)
+				free(peer->issuer);
+			peer->issuer = estrdup(peer->subject);
+			snprintf(statstr, sizeof(statstr),
+			    "assoc %d %d host %s %s", peer->associd,
+			    peer->assoc, peer->subject,
+			    OBJ_nid2ln(temp32));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			break;
+
+		/*
+		 * Decode X509 certificate in ASN.1 format and extract
+		 * the data containing, among other things, subject
+		 * name and public key. In the default identification
+		 * scheme, the certificate trail is followed to a self
+		 * signed trusted certificate.
+		 */
+		case CRYPTO_CERT | CRYPTO_RESP:
+
+			/*
+			 * Discard the message if empty or invalid.
+			 */
+			if (len < VALUE_LEN)
+				break;
+
+			if ((rval = crypto_verify(ep, NULL, peer)) !=
+			    XEVNT_OK)
+				break;
+
+			/*
+			 * Scan the certificate list to delete old
+			 * versions and link the newest version first on
+			 * the list. Then, verify the signature. If the
+			 * certificate is bad or missing, just ignore
+			 * it.
+			 */
+			if ((xinfo = cert_install(ep, peer)) == NULL) {
+				rval = XEVNT_CRT;
+				break;
+			}
+			if ((rval = cert_hike(peer, xinfo)) != XEVNT_OK)
+				break;
+
+			/*
+			 * We plug in the public key and lifetime from
+			 * the first certificate received. However, note
+			 * that this certificate might not be signed by
+			 * the server, so we can't check the
+			 * signature/digest NID.
+			 */
+			if (peer->pkey == NULL) {
+				puch = xinfo->cert.ptr;
+				cert = d2i_X509(NULL, &puch,
+				    ntohl(xinfo->cert.vallen));
+				peer->pkey = X509_get_pubkey(cert);
+				X509_free(cert);
+			}
+			peer->flash &= ~TEST8;
+			temp32 = xinfo->nid;
+			snprintf(statstr, sizeof(statstr),
+			    "cert %s %s 0x%x %s (%u) fs %u",
+			    xinfo->subject, xinfo->issuer, xinfo->flags,
+			    OBJ_nid2ln(temp32), temp32,
+			    ntohl(ep->fstamp));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			break;
+
+		/*
+		 * Schnorr (IFF) identity scheme. This scheme is
+		 * designed for use with shared secret server group keys
+		 * and where the certificate may be generated by a third
+		 * party. The client sends a challenge to the server,
+		 * which performs a calculation and returns the result.
+		 * A positive result is possible only if both client and
+		 * server contain the same secret group key.
+		 */
+		case CRYPTO_IFF | CRYPTO_RESP:
+
+			/*
+			 * Discard the message if invalid.
+			 */
+			if ((rval = crypto_verify(ep, NULL, peer)) !=
+			    XEVNT_OK)
+				break;
+
+			/*
+			 * If the challenge matches the response, the
+			 * server public key, signature and identity are
+			 * all verified at the same time. The server is
+			 * declared trusted, so we skip further
+			 * certificate exchanges and move immediately to
+			 * the cookie exchange.
+			 */
+			if ((rval = crypto_iff(ep, peer)) != XEVNT_OK)
+				break;
+
+			peer->crypto |= CRYPTO_FLAG_VRFY;
+			peer->flash &= ~TEST8;
+			snprintf(statstr, sizeof(statstr), "iff %s fs %u",
+			    peer->issuer, ntohl(ep->fstamp));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			break;
+
+		/*
+		 * Guillou-Quisquater (GQ) identity scheme. This scheme
+		 * is designed for use with public certificates carrying
+		 * the GQ public key in an extension field. The client
+		 * sends a challenge to the server, which performs a
+		 * calculation and returns the result. A positive result
+		 * is possible only if both client and server contain
+		 * the same group key and the server has the matching GQ
+		 * private key.
+		 */
+		case CRYPTO_GQ | CRYPTO_RESP:
+
+			/*
+			 * Discard the message if invalid
+			 */
+			if ((rval = crypto_verify(ep, NULL, peer)) !=
+			    XEVNT_OK)
+				break;
+
+			/*
+			 * If the challenge matches the response, the
+			 * server public key, signature and identity are
+			 * all verified at the same time. The server is
+			 * declared trusted, so we skip further
+			 * certificate exchanges and move immediately to
+			 * the cookie exchange.
+			 */
+			if ((rval = crypto_gq(ep, peer)) != XEVNT_OK)
+				break;
+
+			peer->crypto |= CRYPTO_FLAG_VRFY;
+			peer->flash &= ~TEST8;
+			snprintf(statstr, sizeof(statstr), "gq %s fs %u",
+			    peer->issuer, ntohl(ep->fstamp));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			break;
+
+		/*
+		 * Mu-Varadharajan (MV) identity scheme. This scheme is
+		 * designed for use with three levels of trust, trusted
+		 * host, server and client. The trusted host key is
+		 * opaque to servers and clients; the server keys are
+		 * opaque to clients and each client key is different.
+		 * Client keys can be revoked without requiring new key
+		 * generations.
+		 */
+		case CRYPTO_MV | CRYPTO_RESP:
+
+			/*
+			 * Discard the message if invalid.
+			 */
+			if ((rval = crypto_verify(ep, NULL, peer)) !=
+			    XEVNT_OK)
+				break;
+
+			/*
+			 * If the challenge matches the response, the
+			 * server public key, signature and identity are
+			 * all verified at the same time. The server is
+			 * declared trusted, so we skip further
+			 * certificate exchanges and move immediately to
+			 * the cookie exchange.
+			 */
+			if ((rval = crypto_mv(ep, peer)) != XEVNT_OK)
+				break;
+
+			peer->crypto |= CRYPTO_FLAG_VRFY;
+			peer->flash &= ~TEST8;
+			snprintf(statstr, sizeof(statstr), "mv %s fs %u",
+			    peer->issuer, ntohl(ep->fstamp));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			break;
+
+
+		/*
+		 * Cookie response in client and symmetric modes. If the
+		 * cookie bit is set, the working cookie is the EXOR of
+		 * the current and new values.
+		 */
+		case CRYPTO_COOK | CRYPTO_RESP:
+
+			/*
+			 * Discard the message if invalid or signature
+			 * not verified with respect to the cookie
+			 * values.
+			 */
+			if ((rval = crypto_verify(ep, &peer->cookval,
+			    peer)) != XEVNT_OK)
+				break;
+
+			/*
+			 * Decrypt the cookie, hunting all the time for
+			 * errors.
+			 */
+			if (vallen == (u_int)EVP_PKEY_size(host_pkey)) {
+				if (RSA_private_decrypt(vallen,
+				    (u_char *)ep->pkt,
+				    (u_char *)&temp32,
+				    host_pkey->pkey.rsa,
+				    RSA_PKCS1_OAEP_PADDING) <= 0) {
+					rval = XEVNT_CKY;
+					break;
+				} else {
+					cookie = ntohl(temp32);
+				}
+			} else {
+				rval = XEVNT_CKY;
+				break;
+			}
+
+			/*
+			 * Install cookie values and light the cookie
+			 * bit. If this is not broadcast client mode, we
+			 * are done here.
+			 */
+			key_expire(peer);
+			if (hismode == MODE_ACTIVE || hismode ==
+			    MODE_PASSIVE)
+				peer->pcookie = peer->hcookie ^ cookie;
+			else
+				peer->pcookie = cookie;
+			peer->crypto |= CRYPTO_FLAG_COOK;
+			peer->flash &= ~TEST8;
+			snprintf(statstr, sizeof(statstr),
+			    "cook %x ts %u fs %u", peer->pcookie,
+			    ntohl(ep->tstamp), ntohl(ep->fstamp));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			break;
+
+		/*
+		 * Install autokey values in broadcast client and
+		 * symmetric modes. We have to do this every time the
+		 * sever/peer cookie changes or a new keylist is
+		 * rolled. Ordinarily, this is automatic as this message
+		 * is piggybacked on the first NTP packet sent upon
+		 * either of these events. Note that a broadcast client
+		 * or symmetric peer can receive this response without a
+		 * matching request.
+		 */
+		case CRYPTO_AUTO | CRYPTO_RESP:
+
+			/*
+			 * Discard the message if invalid or signature
+			 * not verified with respect to the receive
+			 * autokey values.
+			 */
+			if ((rval = crypto_verify(ep, &peer->recval,
+			    peer)) != XEVNT_OK) 
+				break;
+
+			/*
+			 * Discard the message if a broadcast client and
+			 * the association ID does not match. This might
+			 * happen if a broacast server restarts the
+			 * protocol. A protocol restart will occur at
+			 * the next ASSOC message.
+			 */
+			if ((peer->cast_flags & MDF_BCLNT) &&
+			    peer->assoc != associd)
+				break;
+
+			/*
+			 * Install autokey values and light the
+			 * autokey bit. This is not hard.
+			 */
+			if (ep->tstamp == 0)
+				break;
+
+			if (peer->recval.ptr == NULL)
+				peer->recval.ptr =
+				    emalloc(sizeof(struct autokey));
+			bp = (struct autokey *)peer->recval.ptr;
+			peer->recval.tstamp = ep->tstamp;
+			peer->recval.fstamp = ep->fstamp;
+			ap = (struct autokey *)ep->pkt;
+			bp->seq = ntohl(ap->seq);
+			bp->key = ntohl(ap->key);
+			peer->pkeyid = bp->key;
+			peer->crypto |= CRYPTO_FLAG_AUTO;
+			peer->flash &= ~TEST8;
+			snprintf(statstr, sizeof(statstr), 
+			    "auto seq %d key %x ts %u fs %u", bp->seq,
+			    bp->key, ntohl(ep->tstamp),
+			    ntohl(ep->fstamp));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			break;
+	
+		/*
+		 * X509 certificate sign response. Validate the
+		 * certificate signed by the server and install. Later
+		 * this can be provided to clients of this server in
+		 * lieu of the self signed certificate in order to
+		 * validate the public key.
+		 */
+		case CRYPTO_SIGN | CRYPTO_RESP:
+
+			/*
+			 * Discard the message if invalid.
+			 */
+			if ((rval = crypto_verify(ep, NULL, peer)) !=
+			    XEVNT_OK)
+				break;
+
+			/*
+			 * Scan the certificate list to delete old
+			 * versions and link the newest version first on
+			 * the list.
+			 */
+			if ((xinfo = cert_install(ep, peer)) == NULL) {
+				rval = XEVNT_CRT;
+				break;
+			}
+			peer->crypto |= CRYPTO_FLAG_SIGN;
+			peer->flash &= ~TEST8;
+			temp32 = xinfo->nid;
+			snprintf(statstr, sizeof(statstr),
+			    "sign %s %s 0x%x %s (%u) fs %u",
+			    xinfo->subject, xinfo->issuer, xinfo->flags,
+			    OBJ_nid2ln(temp32), temp32,
+			    ntohl(ep->fstamp));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			break;
+
+		/*
+		 * Install leapseconds values. While the leapsecond
+		 * values epoch, TAI offset and values expiration epoch
+		 * are retained, only the current TAI offset is provided
+		 * via the kernel to other applications.
+		 */
+		case CRYPTO_LEAP | CRYPTO_RESP:
+			/*
+			 * Discard the message if invalid. We can't
+			 * compare the value timestamps here, as they
+			 * can be updated by different servers.
+			 */
+			if ((rval = crypto_verify(ep, NULL, peer)) !=
+			    XEVNT_OK)
+				break;
+
+			/*
+			 * If the packet leap values are more recent
+			 * than the stored ones, install the new leap
+			 * values and recompute the signatures.
+			 */
+			if (leapsec_add_fix(ntohl(ep->pkt[0]),
+					    ntohl(ep->pkt[1]),
+					    ntohl(ep->pkt[2]),
+					    NULL))
+			{
+				leap_signature_t lsig;
+
+				leapsec_getsig(&lsig);
+				tai_leap.tstamp = ep->tstamp;
+				tai_leap.fstamp = ep->fstamp;
+				tai_leap.vallen = ep->vallen;
+				crypto_update();
+				mprintf_event(EVNT_TAI, peer,
+				    "%d leap %s expire %s", lsig.taiof,
+				    fstostr(lsig.ttime),
+				    fstostr(lsig.etime));
+			}
+			peer->crypto |= CRYPTO_FLAG_LEAP;
+			peer->flash &= ~TEST8;
+			snprintf(statstr, sizeof(statstr),
+			    "leap TAI offset %d at %u expire %u fs %u",
+			    ntohl(ep->pkt[0]), ntohl(ep->pkt[1]),
+			    ntohl(ep->pkt[2]), ntohl(ep->fstamp));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			break;
+
+		/*
+		 * We come here in symmetric modes for miscellaneous
+		 * commands that have value fields but are processed on
+		 * the transmit side. All we need do here is check for
+		 * valid field length. Note that ASSOC is handled
+		 * separately.
+		 */
+		case CRYPTO_CERT:
+		case CRYPTO_IFF:
+		case CRYPTO_GQ:
+		case CRYPTO_MV:
+		case CRYPTO_COOK:
+		case CRYPTO_SIGN:
+			if (len < VALUE_LEN) {
+				rval = XEVNT_LEN;
+				break;
+			}
+			/* fall through */
+
+		/*
+		 * We come here in symmetric modes for requests
+		 * requiring a response (above plus AUTO and LEAP) and
+		 * for responses. If a request, save the extension field
+		 * for later; invalid requests will be caught on the
+		 * transmit side. If an error or invalid response,
+		 * declare a protocol error.
+		 */
+		default:
+			if (code & (CRYPTO_RESP | CRYPTO_ERROR)) {
+				rval = XEVNT_ERR;
+			} else if (peer->cmmd == NULL) {
+				fp = emalloc(len);
+				memcpy(fp, ep, len);
+				peer->cmmd = fp;
+			}
+		}
+
+		/*
+		 * The first error found terminates the extension field
+		 * scan and we return the laundry to the caller.
+		 */
+		if (rval != XEVNT_OK) {
+			snprintf(statstr, sizeof(statstr),
+			    "%04x %d %02x %s", htonl(ep->opcode),
+			    associd, rval, eventstr(rval));
+			record_crypto_stats(&peer->srcadr, statstr);
+#ifdef DEBUG
+			if (debug)
+				printf("crypto_recv: %s\n", statstr);
+#endif
+			return (rval);
+		}
+		authlen += (len + 3) / 4 * 4;
+	}
+	return (rval);
+}
+
+
+/*
+ * crypto_xmit - construct extension fields
+ *
+ * This routine is called both when an association is configured and
+ * when one is not. The only case where this matters is to retrieve the
+ * autokey information, in which case the caller has to provide the
+ * association ID to match the association.
+ *
+ * Side effect: update the packet offset.
+ *
+ * Errors
+ * XEVNT_OK	success
+ * XEVNT_CRT	bad or missing certificate
+ * XEVNT_ERR	protocol error
+ * XEVNT_LEN	bad field format or length
+ * XEVNT_PER	host certificate expired
+ */
+int
+crypto_xmit(
+	struct peer *peer,	/* peer structure pointer */
+	struct pkt *xpkt,	/* transmit packet pointer */
+	struct recvbuf *rbufp,	/* receive buffer pointer */
+	int	start,		/* offset to extension field */
+	struct exten *ep,	/* extension pointer */
+	keyid_t cookie		/* session cookie */
+	)
+{
+	struct exten *fp;	/* extension pointers */
+	struct cert_info *cp, *xp, *yp; /* cert info/value pointer */
+	sockaddr_u *srcadr_sin; /* source address */
+	u_int32	*pkt;		/* packet pointer */
+	u_int	opcode;		/* extension field opcode */
+	char	certname[MAXHOSTNAME + 1]; /* subject name buffer */
+	char	statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
+	tstamp_t tstamp;
+	struct calendar tscal;
+	u_int	vallen;
+	struct value vtemp;
+	associd_t associd;
+	int	rval;
+	int	len;
+	keyid_t tcookie;
+
+	/*
+	 * Generate the requested extension field request code, length
+	 * and association ID. If this is a response and the host is not
+	 * synchronized, light the error bit and go home.
+	 */
+	pkt = (u_int32 *)xpkt + start / 4;
+	fp = (struct exten *)pkt;
+	opcode = ntohl(ep->opcode);
+	if (peer != NULL) {
+		srcadr_sin = &peer->srcadr;
+		if (!(opcode & CRYPTO_RESP))
+			peer->opcode = ep->opcode;
+	} else {
+		srcadr_sin = &rbufp->recv_srcadr;
+	}
+	associd = (associd_t) ntohl(ep->associd);
+	len = 8;
+	fp->opcode = htonl((opcode & 0xffff0000) | len);
+	fp->associd = ep->associd;
+	rval = XEVNT_OK;
+	tstamp = crypto_time();
+	switch (opcode & 0xffff0000) {
+
+	/*
+	 * Send association request and response with status word and
+	 * host name. Note, this message is not signed and the filestamp
+	 * contains only the status word.
+	 */
+	case CRYPTO_ASSOC:
+	case CRYPTO_ASSOC | CRYPTO_RESP:
+		len = crypto_send(fp, &hostval, start);
+		fp->fstamp = htonl(crypto_flags);
+		break;
+
+	/*
+	 * Send certificate request. Use the values from the extension
+	 * field.
+	 */
+	case CRYPTO_CERT:
+		memset(&vtemp, 0, sizeof(vtemp));
+		vtemp.tstamp = ep->tstamp;
+		vtemp.fstamp = ep->fstamp;
+		vtemp.vallen = ep->vallen;
+		vtemp.ptr = (u_char *)ep->pkt;
+		len = crypto_send(fp, &vtemp, start);
+		break;
+
+	/*
+	 * Send sign request. Use the host certificate, which is self-
+	 * signed and may or may not be trusted.
+	 */
+	case CRYPTO_SIGN:
+		(void)ntpcal_ntp_to_date(&tscal, tstamp, NULL);
+		if ((calcomp(&tscal, &(cert_host->first)) < 0)
+		|| (calcomp(&tscal, &(cert_host->last)) > 0))
+			rval = XEVNT_PER;
+		else
+			len = crypto_send(fp, &cert_host->cert, start);
+		break;
+
+	/*
+	 * Send certificate response. Use the name in the extension
+	 * field to find the certificate in the cache. If the request
+	 * contains no subject name, assume the name of this host. This
+	 * is for backwards compatibility. Private certificates are
+	 * never sent.
+	 *
+	 * There may be several certificates matching the request. First
+	 * choice is a self-signed trusted certificate; second choice is
+	 * any certificate signed by another host. There is no third
+	 * choice. 
+	 */
+	case CRYPTO_CERT | CRYPTO_RESP:
+		vallen = ntohl(ep->vallen);
+		if (vallen == 0 || vallen > MAXHOSTNAME) {
+			rval = XEVNT_LEN;
+			break;
+		}
+
+		/*
+		 * Find all public valid certificates with matching
+		 * subject. If a self-signed, trusted certificate is
+		 * found, use that certificate. If not, use the last non
+		 * self-signed certificate.
+		 */
+		memcpy(certname, ep->pkt, vallen);
+		certname[vallen] = '\0';
+		xp = yp = NULL;
+		for (cp = cinfo; cp != NULL; cp = cp->link) {
+			if (cp->flags & (CERT_PRIV | CERT_ERROR))
+				continue;
+
+			if (strcmp(certname, cp->subject) != 0)
+				continue;
+
+			if (strcmp(certname, cp->issuer) != 0)
+				yp = cp;
+			else if (cp ->flags & CERT_TRUST)
+				xp = cp;
+			continue;
+		}
+
+		/*
+		 * Be careful who you trust. If the certificate is not
+		 * found, return an empty response. Note that we dont
+		 * enforce lifetimes here.
+		 *
+		 * The timestamp and filestamp are taken from the
+		 * certificate value structure. For all certificates the
+		 * timestamp is the latest signature update time. For
+		 * host and imported certificates the filestamp is the
+		 * creation epoch. For signed certificates the filestamp
+		 * is the creation epoch of the trusted certificate at
+		 * the root of the certificate trail. In principle, this
+		 * allows strong checking for signature masquerade.
+		 */
+		if (xp == NULL)
+			xp = yp;
+		if (xp == NULL)
+			break;
+
+		if (tstamp == 0)
+			break;
+
+		len = crypto_send(fp, &xp->cert, start);
+		break;
+
+	/*
+	 * Send challenge in Schnorr (IFF) identity scheme.
+	 */
+	case CRYPTO_IFF:
+		if (peer == NULL)
+			break;		/* hack attack */
+
+		if ((rval = crypto_alice(peer, &vtemp)) == XEVNT_OK) {
+			len = crypto_send(fp, &vtemp, start);
+			value_free(&vtemp);
+		}
+		break;
+
+	/*
+	 * Send response in Schnorr (IFF) identity scheme.
+	 */
+	case CRYPTO_IFF | CRYPTO_RESP:
+		if ((rval = crypto_bob(ep, &vtemp)) == XEVNT_OK) {
+			len = crypto_send(fp, &vtemp, start);
+			value_free(&vtemp);
+		}
+		break;
+
+	/*
+	 * Send challenge in Guillou-Quisquater (GQ) identity scheme.
+	 */
+	case CRYPTO_GQ:
+		if (peer == NULL)
+			break;		/* hack attack */
+
+		if ((rval = crypto_alice2(peer, &vtemp)) == XEVNT_OK) {
+			len = crypto_send(fp, &vtemp, start);
+			value_free(&vtemp);
+		}
+		break;
+
+	/*
+	 * Send response in Guillou-Quisquater (GQ) identity scheme.
+	 */
+	case CRYPTO_GQ | CRYPTO_RESP:
+		if ((rval = crypto_bob2(ep, &vtemp)) == XEVNT_OK) {
+			len = crypto_send(fp, &vtemp, start);
+			value_free(&vtemp);
+		}
+		break;
+
+	/*
+	 * Send challenge in MV identity scheme.
+	 */
+	case CRYPTO_MV:
+		if (peer == NULL)
+			break;		/* hack attack */
+
+		if ((rval = crypto_alice3(peer, &vtemp)) == XEVNT_OK) {
+			len = crypto_send(fp, &vtemp, start);
+			value_free(&vtemp);
+		}
+		break;
+
+	/*
+	 * Send response in MV identity scheme.
+	 */
+	case CRYPTO_MV | CRYPTO_RESP:
+		if ((rval = crypto_bob3(ep, &vtemp)) == XEVNT_OK) {
+			len = crypto_send(fp, &vtemp, start);
+			value_free(&vtemp);
+		}
+		break;
+
+	/*
+	 * Send certificate sign response. The integrity of the request
+	 * certificate has already been verified on the receive side.
+	 * Sign the response using the local server key. Use the
+	 * filestamp from the request and use the timestamp as the
+	 * current time. Light the error bit if the certificate is
+	 * invalid or contains an unverified signature.
+	 */
+	case CRYPTO_SIGN | CRYPTO_RESP:
+		if ((rval = cert_sign(ep, &vtemp)) == XEVNT_OK) {
+			len = crypto_send(fp, &vtemp, start);
+			value_free(&vtemp);
+		}
+		break;
+
+	/*
+	 * Send public key and signature. Use the values from the public
+	 * key.
+	 */
+	case CRYPTO_COOK:
+		len = crypto_send(fp, &pubkey, start);
+		break;
+
+	/*
+	 * Encrypt and send cookie and signature. Light the error bit if
+	 * anything goes wrong.
+	 */
+	case CRYPTO_COOK | CRYPTO_RESP:
+		if ((opcode & 0xffff) < VALUE_LEN) {
+			rval = XEVNT_LEN;
+			break;
+		}
+		if (peer == NULL)
+			tcookie = cookie;
+		else
+			tcookie = peer->hcookie;
+		if ((rval = crypto_encrypt(ep, &vtemp, &tcookie)) ==
+		    XEVNT_OK) {
+			len = crypto_send(fp, &vtemp, start);
+			value_free(&vtemp);
+		}
+		break;
+
+	/*
+	 * Find peer and send autokey data and signature in broadcast
+	 * server and symmetric modes. Use the values in the autokey
+	 * structure. If no association is found, either the server has
+	 * restarted with new associations or some perp has replayed an
+	 * old message, in which case light the error bit.
+	 */
+	case CRYPTO_AUTO | CRYPTO_RESP:
+		if (peer == NULL) {
+			if ((peer = findpeerbyassoc(associd)) == NULL) {
+				rval = XEVNT_ERR;
+				break;
+			}
+		}
+		peer->flags &= ~FLAG_ASSOC;
+		len = crypto_send(fp, &peer->sndval, start);
+		break;
+
+	/*
+	 * Send leapseconds values and signature. Use the values from
+	 * the tai structure. If no table has been loaded, just send an
+	 * empty request.
+	 */
+	case CRYPTO_LEAP | CRYPTO_RESP:
+		len = crypto_send(fp, &tai_leap, start);
+		break;
+
+	/*
+	 * Default - Send a valid command for unknown requests; send
+	 * an error response for unknown resonses.
+	 */
+	default:
+		if (opcode & CRYPTO_RESP)
+			rval = XEVNT_ERR;
+	}
+
+	/*
+	 * In case of error, flame the log. If a request, toss the
+	 * puppy; if a response, return so the sender can flame, too.
+	 */
+	if (rval != XEVNT_OK) {
+		u_int32	uint32;
+
+		uint32 = CRYPTO_ERROR;
+		opcode |= uint32;
+		fp->opcode |= htonl(uint32);
+		snprintf(statstr, sizeof(statstr),
+		    "%04x %d %02x %s", opcode, associd, rval,
+		    eventstr(rval));
+		record_crypto_stats(srcadr_sin, statstr);
+#ifdef DEBUG
+		if (debug)
+			printf("crypto_xmit: %s\n", statstr);
+#endif
+		if (!(opcode & CRYPTO_RESP))
+			return (0);
+	}
+#ifdef DEBUG
+	if (debug)
+		printf(
+		    "crypto_xmit: flags 0x%x offset %d len %d code 0x%x associd %d\n",
+		    crypto_flags, start, len, opcode >> 16, associd);
+#endif
+	return (len);
+}
+
+
+/*
+ * crypto_verify - verify the extension field value and signature
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ERR	protocol error
+ * XEVNT_FSP	bad filestamp
+ * XEVNT_LEN	bad field format or length
+ * XEVNT_PUB	bad or missing public key
+ * XEVNT_SGL	bad signature length
+ * XEVNT_SIG	signature not verified
+ * XEVNT_TSP	bad timestamp
+ */
+static int
+crypto_verify(
+	struct exten *ep,	/* extension pointer */
+	struct value *vp,	/* value pointer */
+	struct peer *peer	/* peer structure pointer */
+	)
+{
+	EVP_PKEY *pkey;		/* server public key */
+	EVP_MD_CTX ctx;		/* signature context */
+	tstamp_t tstamp, tstamp1 = 0; /* timestamp */
+	tstamp_t fstamp, fstamp1 = 0; /* filestamp */
+	u_int	vallen;		/* value length */
+	u_int	siglen;		/* signature length */
+	u_int	opcode, len;
+	int	i;
+
+	/*
+	 * We are extremely parannoyed. We require valid opcode, length,
+	 * association ID, timestamp, filestamp, public key, digest,
+	 * signature length and signature, where relevant. Note that
+	 * preliminary length checks are done in the main loop.
+	 */
+	len = ntohl(ep->opcode) & 0x0000ffff;
+	opcode = ntohl(ep->opcode) & 0xffff0000;
+
+	/*
+	 * Check for valid value header, association ID and extension
+	 * field length. Remember, it is not an error to receive an
+	 * unsolicited response; however, the response ID must match
+	 * the association ID.
+	 */
+	if (opcode & CRYPTO_ERROR)
+		return (XEVNT_ERR);
+
+ 	if (len < VALUE_LEN)
+		return (XEVNT_LEN);
+
+	if (opcode == (CRYPTO_AUTO | CRYPTO_RESP) && (peer->pmode ==
+	    MODE_BROADCAST || (peer->cast_flags & MDF_BCLNT))) {
+		if (ntohl(ep->associd) != peer->assoc)
+			return (XEVNT_ERR);
+	} else {
+		if (ntohl(ep->associd) != peer->associd)
+			return (XEVNT_ERR);
+	}
+
+	/*
+	 * We have a valid value header. Check for valid value and
+	 * signature field lengths. The extension field length must be
+	 * long enough to contain the value header, value and signature.
+	 * Note both the value and signature field lengths are rounded
+	 * up to the next word (4 octets).
+	 */
+	vallen = ntohl(ep->vallen);
+	if (vallen == 0)
+		return (XEVNT_LEN);
+
+	i = (vallen + 3) / 4;
+	siglen = ntohl(ep->pkt[i++]);
+	if (len < VALUE_LEN + ((vallen + 3) / 4) * 4 + ((siglen + 3) /
+	    4) * 4)
+		return (XEVNT_LEN);
+
+	/*
+	 * Check for valid timestamp and filestamp. If the timestamp is
+	 * zero, the sender is not synchronized and signatures are
+	 * not possible. If nonzero the timestamp must not precede the
+	 * filestamp. The timestamp and filestamp must not precede the
+	 * corresponding values in the value structure, if present.
+ 	 */
+	tstamp = ntohl(ep->tstamp);
+	fstamp = ntohl(ep->fstamp);
+	if (tstamp == 0)
+		return (XEVNT_TSP);
+
+	if (tstamp < fstamp)
+		return (XEVNT_TSP);
+
+	if (vp != NULL) {
+		tstamp1 = ntohl(vp->tstamp);
+		fstamp1 = ntohl(vp->fstamp);
+		if (tstamp1 != 0 && fstamp1 != 0) {
+			if (tstamp < tstamp1)
+				return (XEVNT_TSP);
+
+			if ((tstamp < fstamp1 || fstamp < fstamp1))
+				return (XEVNT_FSP);
+		}
+	}
+
+	/*
+	 * At the time the certificate message is validated, the public
+	 * key in the message is not available. Thus, don't try to
+	 * verify the signature.
+	 */
+	if (opcode == (CRYPTO_CERT | CRYPTO_RESP))
+		return (XEVNT_OK);
+
+	/*
+	 * Check for valid signature length, public key and digest
+	 * algorithm.
+	 */
+	if (crypto_flags & peer->crypto & CRYPTO_FLAG_PRIV)
+		pkey = sign_pkey;
+	else
+		pkey = peer->pkey;
+	if (siglen == 0 || pkey == NULL || peer->digest == NULL)
+		return (XEVNT_ERR);
+
+	if (siglen != (u_int)EVP_PKEY_size(pkey))
+		return (XEVNT_SGL);
+
+	/*
+	 * Darn, I thought we would never get here. Verify the
+	 * signature. If the identity exchange is verified, light the
+	 * proventic bit. What a relief.
+	 */
+	EVP_VerifyInit(&ctx, peer->digest);
+	EVP_VerifyUpdate(&ctx, (u_char *)&ep->tstamp, vallen + 12);
+	if (EVP_VerifyFinal(&ctx, (u_char *)&ep->pkt[i], siglen,
+	    pkey) <= 0)
+		return (XEVNT_SIG);
+
+	if (peer->crypto & CRYPTO_FLAG_VRFY)
+		peer->crypto |= CRYPTO_FLAG_PROV;
+	return (XEVNT_OK);
+}
+
+
+/*
+ * crypto_encrypt - construct encrypted cookie and signature from
+ * extension field and cookie
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_CKY	bad or missing cookie
+ * XEVNT_PUB	bad or missing public key
+ */
+static int
+crypto_encrypt(
+	struct exten *ep,	/* extension pointer */
+	struct value *vp,	/* value pointer */
+	keyid_t	*cookie		/* server cookie */
+	)
+{
+	EVP_PKEY *pkey;		/* public key */
+	EVP_MD_CTX ctx;		/* signature context */
+	tstamp_t tstamp;	/* NTP timestamp */
+	u_int32	temp32;
+	u_int	len;
+	const u_char *ptr;
+	u_char *puch;
+
+	/*
+	 * Extract the public key from the request.
+	 */
+	len = ntohl(ep->vallen);
+	ptr = (void *)ep->pkt;
+	pkey = d2i_PublicKey(EVP_PKEY_RSA, NULL, &ptr, len);
+	if (pkey == NULL) {
+		msyslog(LOG_ERR, "crypto_encrypt: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		return (XEVNT_PUB);
+	}
+
+	/*
+	 * Encrypt the cookie, encode in ASN.1 and sign.
+	 */
+	memset(vp, 0, sizeof(struct value));
+	tstamp = crypto_time();
+	vp->tstamp = htonl(tstamp);
+	vp->fstamp = hostval.tstamp;
+	len = EVP_PKEY_size(pkey);
+	vp->vallen = htonl(len);
+	vp->ptr = emalloc(len);
+	puch = vp->ptr;
+	temp32 = htonl(*cookie);
+	if (RSA_public_encrypt(4, (u_char *)&temp32, puch,
+	    pkey->pkey.rsa, RSA_PKCS1_OAEP_PADDING) <= 0) {
+		msyslog(LOG_ERR, "crypto_encrypt: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		free(vp->ptr);
+		EVP_PKEY_free(pkey);
+		return (XEVNT_CKY);
+	}
+	EVP_PKEY_free(pkey);
+	if (tstamp == 0)
+		return (XEVNT_OK);
+
+	vp->sig = emalloc(sign_siglen);
+	EVP_SignInit(&ctx, sign_digest);
+	EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
+	EVP_SignUpdate(&ctx, vp->ptr, len);
+	if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
+		vp->siglen = htonl(sign_siglen);
+	return (XEVNT_OK);
+}
+
+
+/*
+ * crypto_ident - construct extension field for identity scheme
+ *
+ * This routine determines which identity scheme is in use and
+ * constructs an extension field for that scheme.
+ *
+ * Returns
+ * CRYTPO_IFF	IFF scheme
+ * CRYPTO_GQ	GQ scheme
+ * CRYPTO_MV	MV scheme
+ * CRYPTO_NULL	no available scheme
+ */
+u_int
+crypto_ident(
+	struct peer *peer	/* peer structure pointer */
+	)
+{
+	char		filename[MAXFILENAME];
+	const char *	scheme_name;
+	u_int		scheme_id;
+
+	/*
+	 * We come here after the group trusted host has been found; its
+	 * name defines the group name. Search the key cache for all
+	 * keys matching the same group name in order IFF, GQ and MV.
+	 * Use the first one available.
+	 */
+	scheme_name = NULL;
+	if (peer->crypto & CRYPTO_FLAG_IFF) {
+		scheme_name = "iff";
+		scheme_id = CRYPTO_IFF;
+	} else if (peer->crypto & CRYPTO_FLAG_GQ) {
+		scheme_name = "gq";
+		scheme_id = CRYPTO_GQ;
+	} else if (peer->crypto & CRYPTO_FLAG_MV) {
+		scheme_name = "mv";
+		scheme_id = CRYPTO_MV;
+	}
+
+	if (scheme_name != NULL) {
+		snprintf(filename, sizeof(filename), "ntpkey_%spar_%s",
+		    scheme_name, peer->ident);
+		peer->ident_pkey = crypto_key(filename, NULL,
+		    &peer->srcadr);
+		if (peer->ident_pkey != NULL)
+			return scheme_id;
+	}
+
+	msyslog(LOG_NOTICE,
+	    "crypto_ident: no identity parameters found for group %s",
+	    peer->ident);
+
+	return CRYPTO_NULL;
+}
+
+
+/*
+ * crypto_args - construct extension field from arguments
+ *
+ * This routine creates an extension field with current timestamps and
+ * specified opcode, association ID and optional string. Note that the
+ * extension field is created here, but freed after the crypto_xmit()
+ * call in the protocol module.
+ *
+ * Returns extension field pointer (no errors)
+ */
+struct exten *
+crypto_args(
+	struct peer *peer,	/* peer structure pointer */
+	u_int	opcode,		/* operation code */
+	associd_t associd,	/* association ID */
+	char	*str		/* argument string */
+	)
+{
+	tstamp_t tstamp;	/* NTP timestamp */
+	struct exten *ep;	/* extension field pointer */
+	u_int	len;		/* extension field length */
+
+	tstamp = crypto_time();
+	len = sizeof(struct exten);
+	if (str != NULL)
+		len += strlen(str);
+	ep = emalloc_zero(len);
+	if (opcode == 0)
+		return (ep);
+
+	ep->opcode = htonl(opcode + len);
+	ep->associd = htonl(associd);
+	ep->tstamp = htonl(tstamp);
+	ep->fstamp = hostval.tstamp;
+	ep->vallen = 0;
+	if (str != NULL) {
+		ep->vallen = htonl(strlen(str));
+		memcpy((char *)ep->pkt, str, strlen(str));
+	}
+	return (ep);
+}
+
+
+/*
+ * crypto_send - construct extension field from value components
+ *
+ * The value and signature fields are zero-padded to a word boundary.
+ * Note: it is not polite to send a nonempty signature with zero
+ * timestamp or a nonzero timestamp with an empty signature, but those
+ * rules are not enforced here.
+ */
+int
+crypto_send(
+	struct exten *ep,	/* extension field pointer */
+	struct value *vp,	/* value pointer */
+	int	start		/* buffer offset */
+	)
+{
+	u_int	len, vallen, siglen, opcode;
+	int	i, j;
+
+	/*
+	 * Calculate extension field length and check for buffer
+	 * overflow. Leave room for the MAC.
+	 */
+	len = 16;
+	vallen = ntohl(vp->vallen);
+	len += ((vallen + 3) / 4 + 1) * 4; 
+	siglen = ntohl(vp->siglen);
+	len += ((siglen + 3) / 4 + 1) * 4; 
+	if (start + len > sizeof(struct pkt) - MAX_MAC_LEN)
+		return (0);
+
+	/*
+	 * Copy timestamps.
+	 */
+	ep->tstamp = vp->tstamp;
+	ep->fstamp = vp->fstamp;
+	ep->vallen = vp->vallen;
+
+	/*
+	 * Copy value. If the data field is empty or zero length,
+	 * encode an empty value with length zero.
+	 */
+	i = 0;
+	if (vallen > 0 && vp->ptr != NULL) {
+		j = vallen / 4;
+		if (j * 4 < (int)vallen)
+			ep->pkt[i + j++] = 0;
+		memcpy(&ep->pkt[i], vp->ptr, vallen);
+		i += j;
+	}
+
+	/*
+	 * Copy signature. If the signature field is empty or zero
+	 * length, encode an empty signature with length zero.
+	 */
+	ep->pkt[i++] = vp->siglen;
+	if (siglen > 0 && vp->sig != NULL) {
+		j = siglen / 4;
+		if (j * 4 < (int)siglen)
+			ep->pkt[i + j++] = 0;
+		memcpy(&ep->pkt[i], vp->sig, siglen);
+		i += j;
+	}
+	opcode = ntohl(ep->opcode);
+	ep->opcode = htonl((opcode & 0xffff0000) | len); 
+	return (len);
+}
+
+
+/*
+ * crypto_update - compute new public value and sign extension fields
+ *
+ * This routine runs periodically, like once a day, and when something
+ * changes. It updates the timestamps on three value structures and one
+ * value structure list, then signs all the structures:
+ *
+ * hostval	host name (not signed)
+ * pubkey	public key
+ * cinfo	certificate info/value list
+ * tai_leap	leap values
+ *
+ * Filestamps are proventic data, so this routine runs only when the
+ * host is synchronized to a proventicated source. Thus, the timestamp
+ * is proventic and can be used to deflect clogging attacks.
+ *
+ * Returns void (no errors)
+ */
+void
+crypto_update(void)
+{
+	EVP_MD_CTX ctx;		/* message digest context */
+	struct cert_info *cp;	/* certificate info/value */
+	char	statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
+	u_int32	*ptr;
+	u_int	len;
+	leap_signature_t lsig;
+
+	hostval.tstamp = htonl(crypto_time());
+	if (hostval.tstamp == 0)
+		return;
+
+
+	/*
+	 * Sign public key and timestamps. The filestamp is derived from
+	 * the host key file extension from wherever the file was
+	 * generated. 
+	 */
+	if (pubkey.vallen != 0) {
+		pubkey.tstamp = hostval.tstamp;
+		pubkey.siglen = 0;
+		if (pubkey.sig == NULL)
+			pubkey.sig = emalloc(sign_siglen);
+		EVP_SignInit(&ctx, sign_digest);
+		EVP_SignUpdate(&ctx, (u_char *)&pubkey, 12);
+		EVP_SignUpdate(&ctx, pubkey.ptr, ntohl(pubkey.vallen));
+		if (EVP_SignFinal(&ctx, pubkey.sig, &len, sign_pkey))
+			pubkey.siglen = htonl(sign_siglen);
+	}
+
+	/*
+	 * Sign certificates and timestamps. The filestamp is derived
+	 * from the certificate file extension from wherever the file
+	 * was generated. Note we do not throw expired certificates
+	 * away; they may have signed younger ones.
+	 */
+	for (cp = cinfo; cp != NULL; cp = cp->link) {
+		cp->cert.tstamp = hostval.tstamp;
+		cp->cert.siglen = 0;
+		if (cp->cert.sig == NULL)
+			cp->cert.sig = emalloc(sign_siglen);
+		EVP_SignInit(&ctx, sign_digest);
+		EVP_SignUpdate(&ctx, (u_char *)&cp->cert, 12);
+		EVP_SignUpdate(&ctx, cp->cert.ptr,
+		    ntohl(cp->cert.vallen));
+		if (EVP_SignFinal(&ctx, cp->cert.sig, &len, sign_pkey))
+			cp->cert.siglen = htonl(sign_siglen);
+	}
+
+	/*
+	 * Sign leapseconds values and timestamps. Note it is not an
+	 * error to return null values.
+	 */
+	tai_leap.tstamp = hostval.tstamp;
+	tai_leap.fstamp = hostval.fstamp;
+	len = 3 * sizeof(u_int32);
+	if (tai_leap.ptr == NULL)
+		tai_leap.ptr = emalloc(len);
+	tai_leap.vallen = htonl(len);
+	ptr = (u_int32 *)tai_leap.ptr;
+	leapsec_getsig(&lsig);
+	ptr[0] = htonl(lsig.taiof);
+	ptr[1] = htonl(lsig.ttime);
+	ptr[2] = htonl(lsig.etime);
+	if (tai_leap.sig == NULL)
+		tai_leap.sig = emalloc(sign_siglen);
+	EVP_SignInit(&ctx, sign_digest);
+	EVP_SignUpdate(&ctx, (u_char *)&tai_leap, 12);
+	EVP_SignUpdate(&ctx, tai_leap.ptr, len);
+	if (EVP_SignFinal(&ctx, tai_leap.sig, &len, sign_pkey))
+		tai_leap.siglen = htonl(sign_siglen);
+	if (lsig.ttime > 0)
+		crypto_flags |= CRYPTO_FLAG_TAI;
+	snprintf(statstr, sizeof(statstr), "signature update ts %u",
+	    ntohl(hostval.tstamp)); 
+	record_crypto_stats(NULL, statstr);
+#ifdef DEBUG
+	if (debug)
+		printf("crypto_update: %s\n", statstr);
+#endif
+}
+
+
+/*
+ * value_free - free value structure components.
+ *
+ * Returns void (no errors)
+ */
+void
+value_free(
+	struct value *vp	/* value structure */
+	)
+{
+	if (vp->ptr != NULL)
+		free(vp->ptr);
+	if (vp->sig != NULL)
+		free(vp->sig);
+	memset(vp, 0, sizeof(struct value));
+}
+
+
+/*
+ * crypto_time - returns current NTP time.
+ *
+ * Returns NTP seconds if in synch, 0 otherwise
+ */
+tstamp_t
+crypto_time()
+{
+	l_fp	tstamp;		/* NTP time */
+
+	L_CLR(&tstamp);
+	if (sys_leap != LEAP_NOTINSYNC)
+		get_systime(&tstamp);
+	return (tstamp.l_ui);
+}
+
+
+/*
+ * asn_to_calendar - convert ASN1_TIME time structure to struct calendar.
+ *
+ */
+static
+void
+asn_to_calendar	(
+	ASN1_TIME *asn1time,	/* pointer to ASN1_TIME structure */
+	struct calendar *pjd	/* pointer to result */
+	)
+{
+	int	len;		/* length of ASN1_TIME string */
+	char	v[24];		/* writable copy of ASN1_TIME string */
+	unsigned long	temp;	/* result from strtoul */
+
+	/*
+	 * Extract time string YYMMDDHHMMSSZ from ASN1 time structure.
+	 * Or YYYYMMDDHHMMSSZ.
+	 * Note that the YY, MM, DD fields start with one, the HH, MM,
+	 * SS fields start with zero and the Z character is ignored.
+	 * Also note that two-digit years less than 50 map to years greater than
+	 * 100. Dontcha love ASN.1? Better than MIL-188.
+	 */
+	len = asn1time->length;
+	NTP_REQUIRE(len < sizeof(v));
+	(void)strncpy(v, (char *)(asn1time->data), len);
+	NTP_REQUIRE(len >= 13);
+	temp = strtoul(v+len-3, NULL, 10);
+	pjd->second = temp;
+	v[len-3] = '\0';
+
+	temp = strtoul(v+len-5, NULL, 10);
+	pjd->minute = temp;
+	v[len-5] = '\0';
+
+	temp = strtoul(v+len-7, NULL, 10);
+	pjd->hour = temp;
+	v[len-7] = '\0';
+
+	temp = strtoul(v+len-9, NULL, 10);
+	pjd->monthday = temp;
+	v[len-9] = '\0';
+
+	temp = strtoul(v+len-11, NULL, 10);
+	pjd->month = temp;
+	v[len-11] = '\0';
+
+	temp = strtoul(v, NULL, 10);
+	/* handle two-digit years */
+	if (temp < 50UL)
+	    temp += 100UL;
+	if (temp < 150UL)
+	    temp += 1900UL;
+	pjd->year = temp;
+
+	pjd->yearday = pjd->weekday = 0;
+	return;
+}
+
+
+/*
+ * bigdig() - compute a BIGNUM MD5 hash of a BIGNUM number.
+ *
+ * Returns void (no errors)
+ */
+static void
+bighash(
+	BIGNUM	*bn,		/* BIGNUM * from */
+	BIGNUM	*bk		/* BIGNUM * to */
+	)
+{
+	EVP_MD_CTX ctx;		/* message digest context */
+	u_char dgst[EVP_MAX_MD_SIZE]; /* message digest */
+	u_char	*ptr;		/* a BIGNUM as binary string */
+	u_int	len;
+
+	len = BN_num_bytes(bn);
+	ptr = emalloc(len);
+	BN_bn2bin(bn, ptr);
+	EVP_DigestInit(&ctx, EVP_md5());
+	EVP_DigestUpdate(&ctx, ptr, len);
+	EVP_DigestFinal(&ctx, dgst, &len);
+	BN_bin2bn(dgst, len, bk);
+	free(ptr);
+}
+
+
+/*
+ ***********************************************************************
+ *								       *
+ * The following routines implement the Schnorr (IFF) identity scheme  *
+ *								       *
+ ***********************************************************************
+ *
+ * The Schnorr (IFF) identity scheme is intended for use when
+ * certificates are generated by some other trusted certificate
+ * authority and the certificate cannot be used to convey public
+ * parameters. There are two kinds of files: encrypted server files that
+ * contain private and public values and nonencrypted client files that
+ * contain only public values. New generations of server files must be
+ * securely transmitted to all servers of the group; client files can be
+ * distributed by any means. The scheme is self contained and
+ * independent of new generations of host keys, sign keys and
+ * certificates.
+ *
+ * The IFF values hide in a DSA cuckoo structure which uses the same
+ * parameters. The values are used by an identity scheme based on DSA
+ * cryptography and described in Stimson p. 285. The p is a 512-bit
+ * prime, g a generator of Zp* and q a 160-bit prime that divides p - 1
+ * and is a qth root of 1 mod p; that is, g^q = 1 mod p. The TA rolls a
+ * private random group key b (0 < b < q) and public key v = g^b, then
+ * sends (p, q, g, b) to the servers and (p, q, g, v) to the clients.
+ * Alice challenges Bob to confirm identity using the protocol described
+ * below.
+ *
+ * How it works
+ *
+ * The scheme goes like this. Both Alice and Bob have the public primes
+ * p, q and generator g. The TA gives private key b to Bob and public
+ * key v to Alice.
+ *
+ * Alice rolls new random challenge r (o < r < q) and sends to Bob in
+ * the IFF request message. Bob rolls new random k (0 < k < q), then
+ * computes y = k + b r mod q and x = g^k mod p and sends (y, hash(x))
+ * to Alice in the response message. Besides making the response
+ * shorter, the hash makes it effectivey impossible for an intruder to
+ * solve for b by observing a number of these messages.
+ * 
+ * Alice receives the response and computes g^y v^r mod p. After a bit
+ * of algebra, this simplifies to g^k. If the hash of this result
+ * matches hash(x), Alice knows that Bob has the group key b. The signed
+ * response binds this knowledge to Bob's private key and the public key
+ * previously received in his certificate.
+ *
+ * crypto_alice - construct Alice's challenge in IFF scheme
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ID	bad or missing group key
+ * XEVNT_PUB	bad or missing public key
+ */
+static int
+crypto_alice(
+	struct peer *peer,	/* peer pointer */
+	struct value *vp	/* value pointer */
+	)
+{
+	DSA	*dsa;		/* IFF parameters */
+	BN_CTX	*bctx;		/* BIGNUM context */
+	EVP_MD_CTX ctx;		/* signature context */
+	tstamp_t tstamp;
+	u_int	len;
+
+	/*
+	 * The identity parameters must have correct format and content.
+	 */
+	if (peer->ident_pkey == NULL) {
+		msyslog(LOG_NOTICE, "crypto_alice: scheme unavailable");
+		return (XEVNT_ID);
+	}
+
+	if ((dsa = peer->ident_pkey->pkey->pkey.dsa) == NULL) {
+		msyslog(LOG_NOTICE, "crypto_alice: defective key");
+		return (XEVNT_PUB);
+	}
+
+	/*
+	 * Roll new random r (0 < r < q).
+	 */
+	if (peer->iffval != NULL)
+		BN_free(peer->iffval);
+	peer->iffval = BN_new();
+	len = BN_num_bytes(dsa->q);
+	BN_rand(peer->iffval, len * 8, -1, 1);	/* r mod q*/
+	bctx = BN_CTX_new();
+	BN_mod(peer->iffval, peer->iffval, dsa->q, bctx);
+	BN_CTX_free(bctx);
+
+	/*
+	 * Sign and send to Bob. The filestamp is from the local file.
+	 */
+	memset(vp, 0, sizeof(struct value));
+	tstamp = crypto_time();
+	vp->tstamp = htonl(tstamp);
+	vp->fstamp = htonl(peer->ident_pkey->fstamp);
+	vp->vallen = htonl(len);
+	vp->ptr = emalloc(len);
+	BN_bn2bin(peer->iffval, vp->ptr);
+	if (tstamp == 0)
+		return (XEVNT_OK);
+
+	vp->sig = emalloc(sign_siglen);
+	EVP_SignInit(&ctx, sign_digest);
+	EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
+	EVP_SignUpdate(&ctx, vp->ptr, len);
+	if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
+		vp->siglen = htonl(sign_siglen);
+	return (XEVNT_OK);
+}
+
+
+/*
+ * crypto_bob - construct Bob's response to Alice's challenge
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ERR	protocol error
+ * XEVNT_ID	bad or missing group key
+ */
+static int
+crypto_bob(
+	struct exten *ep,	/* extension pointer */
+	struct value *vp	/* value pointer */
+	)
+{
+	DSA	*dsa;		/* IFF parameters */
+	DSA_SIG	*sdsa;		/* DSA signature context fake */
+	BN_CTX	*bctx;		/* BIGNUM context */
+	EVP_MD_CTX ctx;		/* signature context */
+	tstamp_t tstamp;	/* NTP timestamp */
+	BIGNUM	*bn, *bk, *r;
+	u_char	*ptr;
+	u_int	len;
+
+	/*
+	 * If the IFF parameters are not valid, something awful
+	 * happened or we are being tormented.
+	 */
+	if (iffkey_info == NULL) {
+		msyslog(LOG_NOTICE, "crypto_bob: scheme unavailable");
+		return (XEVNT_ID);
+	}
+	dsa = iffkey_info->pkey->pkey.dsa;
+
+	/*
+	 * Extract r from the challenge.
+	 */
+	len = ntohl(ep->vallen);
+	if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
+		msyslog(LOG_ERR, "crypto_bob: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		return (XEVNT_ERR);
+	}
+
+	/*
+	 * Bob rolls random k (0 < k < q), computes y = k + b r mod q
+	 * and x = g^k mod p, then sends (y, hash(x)) to Alice.
+	 */
+	bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
+	sdsa = DSA_SIG_new();
+	BN_rand(bk, len * 8, -1, 1);		/* k */
+	BN_mod_mul(bn, dsa->priv_key, r, dsa->q, bctx); /* b r mod q */
+	BN_add(bn, bn, bk);
+	BN_mod(bn, bn, dsa->q, bctx);		/* k + b r mod q */
+	sdsa->r = BN_dup(bn);
+	BN_mod_exp(bk, dsa->g, bk, dsa->p, bctx); /* g^k mod p */
+	bighash(bk, bk);
+	sdsa->s = BN_dup(bk);
+	BN_CTX_free(bctx);
+	BN_free(r); BN_free(bn); BN_free(bk);
+#ifdef DEBUG
+	if (debug > 1)
+		DSA_print_fp(stdout, dsa, 0);
+#endif
+
+	/*
+	 * Encode the values in ASN.1 and sign. The filestamp is from
+	 * the local file.
+	 */
+	len = i2d_DSA_SIG(sdsa, NULL);
+	if (len == 0) {
+		msyslog(LOG_ERR, "crypto_bob: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		DSA_SIG_free(sdsa);
+		return (XEVNT_ERR);
+	}
+	memset(vp, 0, sizeof(struct value));
+	tstamp = crypto_time();
+	vp->tstamp = htonl(tstamp);
+	vp->fstamp = htonl(iffkey_info->fstamp);
+	vp->vallen = htonl(len);
+	ptr = emalloc(len);
+	vp->ptr = ptr;
+	i2d_DSA_SIG(sdsa, &ptr);
+	DSA_SIG_free(sdsa);
+	if (tstamp == 0)
+		return (XEVNT_OK);
+
+	vp->sig = emalloc(sign_siglen);
+	EVP_SignInit(&ctx, sign_digest);
+	EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
+	EVP_SignUpdate(&ctx, vp->ptr, len);
+	if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
+		vp->siglen = htonl(sign_siglen);
+	return (XEVNT_OK);
+}
+
+
+/*
+ * crypto_iff - verify Bob's response to Alice's challenge
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_FSP	bad filestamp
+ * XEVNT_ID	bad or missing group key
+ * XEVNT_PUB	bad or missing public key
+ */
+int
+crypto_iff(
+	struct exten *ep,	/* extension pointer */
+	struct peer *peer	/* peer structure pointer */
+	)
+{
+	DSA	*dsa;		/* IFF parameters */
+	BN_CTX	*bctx;		/* BIGNUM context */
+	DSA_SIG	*sdsa;		/* DSA parameters */
+	BIGNUM	*bn, *bk;
+	u_int	len;
+	const u_char *ptr;
+	int	temp;
+
+	/*
+	 * If the IFF parameters are not valid or no challenge was sent,
+	 * something awful happened or we are being tormented.
+	 */
+	if (peer->ident_pkey == NULL) {
+		msyslog(LOG_NOTICE, "crypto_iff: scheme unavailable");
+		return (XEVNT_ID);
+	}
+	if (ntohl(ep->fstamp) != peer->ident_pkey->fstamp) {
+		msyslog(LOG_NOTICE, "crypto_iff: invalid filestamp %u",
+		    ntohl(ep->fstamp));
+		return (XEVNT_FSP);
+	}
+	if ((dsa = peer->ident_pkey->pkey->pkey.dsa) == NULL) {
+		msyslog(LOG_NOTICE, "crypto_iff: defective key");
+		return (XEVNT_PUB);
+	}
+	if (peer->iffval == NULL) {
+		msyslog(LOG_NOTICE, "crypto_iff: missing challenge");
+		return (XEVNT_ID);
+	}
+
+	/*
+	 * Extract the k + b r and g^k values from the response.
+	 */
+	bctx = BN_CTX_new(); bk = BN_new(); bn = BN_new();
+	len = ntohl(ep->vallen);
+	ptr = (u_char *)ep->pkt;
+	if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
+		BN_free(bn); BN_free(bk); BN_CTX_free(bctx);
+		msyslog(LOG_ERR, "crypto_iff: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		return (XEVNT_ERR);
+	}
+
+	/*
+	 * Compute g^(k + b r) g^(q - b)r mod p.
+	 */
+	BN_mod_exp(bn, dsa->pub_key, peer->iffval, dsa->p, bctx);
+	BN_mod_exp(bk, dsa->g, sdsa->r, dsa->p, bctx);
+	BN_mod_mul(bn, bn, bk, dsa->p, bctx);
+
+	/*
+	 * Verify the hash of the result matches hash(x).
+	 */
+	bighash(bn, bn);
+	temp = BN_cmp(bn, sdsa->s);
+	BN_free(bn); BN_free(bk); BN_CTX_free(bctx);
+	BN_free(peer->iffval);
+	peer->iffval = NULL;
+	DSA_SIG_free(sdsa);
+	if (temp == 0)
+		return (XEVNT_OK);
+
+	msyslog(LOG_NOTICE, "crypto_iff: identity not verified");
+	return (XEVNT_ID);
+}
+
+
+/*
+ ***********************************************************************
+ *								       *
+ * The following routines implement the Guillou-Quisquater (GQ)        *
+ * identity scheme                                                     *
+ *								       *
+ ***********************************************************************
+ *
+ * The Guillou-Quisquater (GQ) identity scheme is intended for use when
+ * the certificate can be used to convey public parameters. The scheme
+ * uses a X509v3 certificate extension field do convey the public key of
+ * a private key known only to servers. There are two kinds of files:
+ * encrypted server files that contain private and public values and
+ * nonencrypted client files that contain only public values. New
+ * generations of server files must be securely transmitted to all
+ * servers of the group; client files can be distributed by any means.
+ * The scheme is self contained and independent of new generations of
+ * host keys and sign keys. The scheme is self contained and independent
+ * of new generations of host keys and sign keys.
+ *
+ * The GQ parameters hide in a RSA cuckoo structure which uses the same
+ * parameters. The values are used by an identity scheme based on RSA
+ * cryptography and described in Stimson p. 300 (with errors). The 512-
+ * bit public modulus is n = p q, where p and q are secret large primes.
+ * The TA rolls private random group key b as RSA exponent. These values
+ * are known to all group members.
+ *
+ * When rolling new certificates, a server recomputes the private and
+ * public keys. The private key u is a random roll, while the public key
+ * is the inverse obscured by the group key v = (u^-1)^b. These values
+ * replace the private and public keys normally generated by the RSA
+ * scheme. Alice challenges Bob to confirm identity using the protocol
+ * described below.
+ *
+ * How it works
+ *
+ * The scheme goes like this. Both Alice and Bob have the same modulus n
+ * and some random b as the group key. These values are computed and
+ * distributed in advance via secret means, although only the group key
+ * b is truly secret. Each has a private random private key u and public
+ * key (u^-1)^b, although not necessarily the same ones. Bob and Alice
+ * can regenerate the key pair from time to time without affecting
+ * operations. The public key is conveyed on the certificate in an
+ * extension field; the private key is never revealed.
+ *
+ * Alice rolls new random challenge r and sends to Bob in the GQ
+ * request message. Bob rolls new random k, then computes y = k u^r mod
+ * n and x = k^b mod n and sends (y, hash(x)) to Alice in the response
+ * message. Besides making the response shorter, the hash makes it
+ * effectivey impossible for an intruder to solve for b by observing
+ * a number of these messages.
+ * 
+ * Alice receives the response and computes y^b v^r mod n. After a bit
+ * of algebra, this simplifies to k^b. If the hash of this result
+ * matches hash(x), Alice knows that Bob has the group key b. The signed
+ * response binds this knowledge to Bob's private key and the public key
+ * previously received in his certificate.
+ *
+ * crypto_alice2 - construct Alice's challenge in GQ scheme
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ID	bad or missing group key
+ * XEVNT_PUB	bad or missing public key
+ */
+static int
+crypto_alice2(
+	struct peer *peer,	/* peer pointer */
+	struct value *vp	/* value pointer */
+	)
+{
+	RSA	*rsa;		/* GQ parameters */
+	BN_CTX	*bctx;		/* BIGNUM context */
+	EVP_MD_CTX ctx;		/* signature context */
+	tstamp_t tstamp;
+	u_int	len;
+
+	/*
+	 * The identity parameters must have correct format and content.
+	 */
+	if (peer->ident_pkey == NULL)
+		return (XEVNT_ID);
+
+	if ((rsa = peer->ident_pkey->pkey->pkey.rsa) == NULL) {
+		msyslog(LOG_NOTICE, "crypto_alice2: defective key");
+		return (XEVNT_PUB);
+	}
+
+	/*
+	 * Roll new random r (0 < r < n).
+	 */
+	if (peer->iffval != NULL)
+		BN_free(peer->iffval);
+	peer->iffval = BN_new();
+	len = BN_num_bytes(rsa->n);
+	BN_rand(peer->iffval, len * 8, -1, 1);	/* r mod n */
+	bctx = BN_CTX_new();
+	BN_mod(peer->iffval, peer->iffval, rsa->n, bctx);
+	BN_CTX_free(bctx);
+
+	/*
+	 * Sign and send to Bob. The filestamp is from the local file.
+	 */
+	memset(vp, 0, sizeof(struct value));
+	tstamp = crypto_time();
+	vp->tstamp = htonl(tstamp);
+	vp->fstamp = htonl(peer->ident_pkey->fstamp);
+	vp->vallen = htonl(len);
+	vp->ptr = emalloc(len);
+	BN_bn2bin(peer->iffval, vp->ptr);
+	if (tstamp == 0)
+		return (XEVNT_OK);
+
+	vp->sig = emalloc(sign_siglen);
+	EVP_SignInit(&ctx, sign_digest);
+	EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
+	EVP_SignUpdate(&ctx, vp->ptr, len);
+	if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
+		vp->siglen = htonl(sign_siglen);
+	return (XEVNT_OK);
+}
+
+
+/*
+ * crypto_bob2 - construct Bob's response to Alice's challenge
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ERR	protocol error
+ * XEVNT_ID	bad or missing group key
+ */
+static int
+crypto_bob2(
+	struct exten *ep,	/* extension pointer */
+	struct value *vp	/* value pointer */
+	)
+{
+	RSA	*rsa;		/* GQ parameters */
+	DSA_SIG	*sdsa;		/* DSA parameters */
+	BN_CTX	*bctx;		/* BIGNUM context */
+	EVP_MD_CTX ctx;		/* signature context */
+	tstamp_t tstamp;	/* NTP timestamp */
+	BIGNUM	*r, *k, *g, *y;
+	u_char	*ptr;
+	u_int	len;
+	int	s_len;
+
+	/*
+	 * If the GQ parameters are not valid, something awful
+	 * happened or we are being tormented.
+	 */
+	if (gqkey_info == NULL) {
+		msyslog(LOG_NOTICE, "crypto_bob2: scheme unavailable");
+		return (XEVNT_ID);
+	}
+	rsa = gqkey_info->pkey->pkey.rsa;
+
+	/*
+	 * Extract r from the challenge.
+	 */
+	len = ntohl(ep->vallen);
+	if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
+		msyslog(LOG_ERR, "crypto_bob2: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		return (XEVNT_ERR);
+	}
+
+	/*
+	 * Bob rolls random k (0 < k < n), computes y = k u^r mod n and
+	 * x = k^b mod n, then sends (y, hash(x)) to Alice. 
+	 */
+	bctx = BN_CTX_new(); k = BN_new(); g = BN_new(); y = BN_new();
+	sdsa = DSA_SIG_new();
+	BN_rand(k, len * 8, -1, 1);		/* k */
+	BN_mod(k, k, rsa->n, bctx);
+	BN_mod_exp(y, rsa->p, r, rsa->n, bctx); /* u^r mod n */
+	BN_mod_mul(y, k, y, rsa->n, bctx);	/* k u^r mod n */
+	sdsa->r = BN_dup(y);
+	BN_mod_exp(g, k, rsa->e, rsa->n, bctx); /* k^b mod n */
+	bighash(g, g);
+	sdsa->s = BN_dup(g);
+	BN_CTX_free(bctx);
+	BN_free(r); BN_free(k); BN_free(g); BN_free(y);
+#ifdef DEBUG
+	if (debug > 1)
+		RSA_print_fp(stdout, rsa, 0);
+#endif
+ 
+	/*
+	 * Encode the values in ASN.1 and sign. The filestamp is from
+	 * the local file.
+	 */
+	len = s_len = i2d_DSA_SIG(sdsa, NULL);
+	if (s_len <= 0) {
+		msyslog(LOG_ERR, "crypto_bob2: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		DSA_SIG_free(sdsa);
+		return (XEVNT_ERR);
+	}
+	memset(vp, 0, sizeof(struct value));
+	tstamp = crypto_time();
+	vp->tstamp = htonl(tstamp);
+	vp->fstamp = htonl(gqkey_info->fstamp);
+	vp->vallen = htonl(len);
+	ptr = emalloc(len);
+	vp->ptr = ptr;
+	i2d_DSA_SIG(sdsa, &ptr);
+	DSA_SIG_free(sdsa);
+	if (tstamp == 0)
+		return (XEVNT_OK);
+
+	vp->sig = emalloc(sign_siglen);
+	EVP_SignInit(&ctx, sign_digest);
+	EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
+	EVP_SignUpdate(&ctx, vp->ptr, len);
+	if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
+		vp->siglen = htonl(sign_siglen);
+	return (XEVNT_OK);
+}
+
+
+/*
+ * crypto_gq - verify Bob's response to Alice's challenge
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ERR	protocol error
+ * XEVNT_FSP	bad filestamp
+ * XEVNT_ID	bad or missing group keys
+ * XEVNT_PUB	bad or missing public key
+ */
+int
+crypto_gq(
+	struct exten *ep,	/* extension pointer */
+	struct peer *peer	/* peer structure pointer */
+	)
+{
+	RSA	*rsa;		/* GQ parameters */
+	BN_CTX	*bctx;		/* BIGNUM context */
+	DSA_SIG	*sdsa;		/* RSA signature context fake */
+	BIGNUM	*y, *v;
+	const u_char *ptr;
+	long	len;
+	u_int	temp;
+
+	/*
+	 * If the GQ parameters are not valid or no challenge was sent,
+	 * something awful happened or we are being tormented. Note that
+	 * the filestamp on the local key file can be greater than on
+	 * the remote parameter file if the keys have been refreshed.
+	 */
+	if (peer->ident_pkey == NULL) {
+		msyslog(LOG_NOTICE, "crypto_gq: scheme unavailable");
+		return (XEVNT_ID);
+	}
+	if (ntohl(ep->fstamp) < peer->ident_pkey->fstamp) {
+		msyslog(LOG_NOTICE, "crypto_gq: invalid filestamp %u",
+		    ntohl(ep->fstamp));
+		return (XEVNT_FSP);
+	}
+	if ((rsa = peer->ident_pkey->pkey->pkey.rsa) == NULL) {
+		msyslog(LOG_NOTICE, "crypto_gq: defective key");
+		return (XEVNT_PUB);
+	}
+	if (peer->iffval == NULL) {
+		msyslog(LOG_NOTICE, "crypto_gq: missing challenge");
+		return (XEVNT_ID);
+	}
+
+	/*
+	 * Extract the y = k u^r and hash(x = k^b) values from the
+	 * response.
+	 */
+	bctx = BN_CTX_new(); y = BN_new(); v = BN_new();
+	len = ntohl(ep->vallen);
+	ptr = (u_char *)ep->pkt;
+	if ((sdsa = d2i_DSA_SIG(NULL, &ptr, len)) == NULL) {
+		BN_CTX_free(bctx); BN_free(y); BN_free(v);
+		msyslog(LOG_ERR, "crypto_gq: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		return (XEVNT_ERR);
+	}
+
+	/*
+	 * Compute v^r y^b mod n.
+	 */
+	if (peer->grpkey == NULL) {
+		msyslog(LOG_NOTICE, "crypto_gq: missing group key");
+		return (XEVNT_ID);
+	}
+	BN_mod_exp(v, peer->grpkey, peer->iffval, rsa->n, bctx);
+						/* v^r mod n */
+	BN_mod_exp(y, sdsa->r, rsa->e, rsa->n, bctx); /* y^b mod n */
+	BN_mod_mul(y, v, y, rsa->n, bctx);	/* v^r y^b mod n */
+
+	/*
+	 * Verify the hash of the result matches hash(x).
+	 */
+	bighash(y, y);
+	temp = BN_cmp(y, sdsa->s);
+	BN_CTX_free(bctx); BN_free(y); BN_free(v);
+	BN_free(peer->iffval);
+	peer->iffval = NULL;
+	DSA_SIG_free(sdsa);
+	if (temp == 0)
+		return (XEVNT_OK);
+
+	msyslog(LOG_NOTICE, "crypto_gq: identity not verified");
+	return (XEVNT_ID);
+}
+
+
+/*
+ ***********************************************************************
+ *								       *
+ * The following routines implement the Mu-Varadharajan (MV) identity  *
+ * scheme                                                              *
+ *								       *
+ ***********************************************************************
+ *
+ * The Mu-Varadharajan (MV) cryptosystem was originally intended when
+ * servers broadcast messages to clients, but clients never send
+ * messages to servers. There is one encryption key for the server and a
+ * separate decryption key for each client. It operated something like a
+ * pay-per-view satellite broadcasting system where the session key is
+ * encrypted by the broadcaster and the decryption keys are held in a
+ * tamperproof set-top box.
+ *
+ * The MV parameters and private encryption key hide in a DSA cuckoo
+ * structure which uses the same parameters, but generated in a
+ * different way. The values are used in an encryption scheme similar to
+ * El Gamal cryptography and a polynomial formed from the expansion of
+ * product terms (x - x[j]), as described in Mu, Y., and V.
+ * Varadharajan: Robust and Secure Broadcasting, Proc. Indocrypt 2001,
+ * 223-231. The paper has significant errors and serious omissions.
+ *
+ * Let q be the product of n distinct primes s1[j] (j = 1...n), where
+ * each s1[j] has m significant bits. Let p be a prime p = 2 * q + 1, so
+ * that q and each s1[j] divide p - 1 and p has M = n * m + 1
+ * significant bits. Let g be a generator of Zp; that is, gcd(g, p - 1)
+ * = 1 and g^q = 1 mod p. We do modular arithmetic over Zq and then
+ * project into Zp* as exponents of g. Sometimes we have to compute an
+ * inverse b^-1 of random b in Zq, but for that purpose we require
+ * gcd(b, q) = 1. We expect M to be in the 500-bit range and n
+ * relatively small, like 30. These are the parameters of the scheme and
+ * they are expensive to compute.
+ *
+ * We set up an instance of the scheme as follows. A set of random
+ * values x[j] mod q (j = 1...n), are generated as the zeros of a
+ * polynomial of order n. The product terms (x - x[j]) are expanded to
+ * form coefficients a[i] mod q (i = 0...n) in powers of x. These are
+ * used as exponents of the generator g mod p to generate the private
+ * encryption key A. The pair (gbar, ghat) of public server keys and the
+ * pairs (xbar[j], xhat[j]) (j = 1...n) of private client keys are used
+ * to construct the decryption keys. The devil is in the details.
+ *
+ * This routine generates a private server encryption file including the
+ * private encryption key E and partial decryption keys gbar and ghat.
+ * It then generates public client decryption files including the public
+ * keys xbar[j] and xhat[j] for each client j. The partial decryption
+ * files are used to compute the inverse of E. These values are suitably
+ * blinded so secrets are not revealed.
+ *
+ * The distinguishing characteristic of this scheme is the capability to
+ * revoke keys. Included in the calculation of E, gbar and ghat is the
+ * product s = prod(s1[j]) (j = 1...n) above. If the factor s1[j] is
+ * subsequently removed from the product and E, gbar and ghat
+ * recomputed, the jth client will no longer be able to compute E^-1 and
+ * thus unable to decrypt the messageblock.
+ *
+ * How it works
+ *
+ * The scheme goes like this. Bob has the server values (p, E, q, gbar,
+ * ghat) and Alice has the client values (p, xbar, xhat).
+ *
+ * Alice rolls new random nonce r mod p and sends to Bob in the MV
+ * request message. Bob rolls random nonce k mod q, encrypts y = r E^k
+ * mod p and sends (y, gbar^k, ghat^k) to Alice.
+ * 
+ * Alice receives the response and computes the inverse (E^k)^-1 from
+ * the partial decryption keys gbar^k, ghat^k, xbar and xhat. She then
+ * decrypts y and verifies it matches the original r. The signed
+ * response binds this knowledge to Bob's private key and the public key
+ * previously received in his certificate.
+ *
+ * crypto_alice3 - construct Alice's challenge in MV scheme
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ID	bad or missing group key
+ * XEVNT_PUB	bad or missing public key
+ */
+static int
+crypto_alice3(
+	struct peer *peer,	/* peer pointer */
+	struct value *vp	/* value pointer */
+	)
+{
+	DSA	*dsa;		/* MV parameters */
+	BN_CTX	*bctx;		/* BIGNUM context */
+	EVP_MD_CTX ctx;		/* signature context */
+	tstamp_t tstamp;
+	u_int	len;
+
+	/*
+	 * The identity parameters must have correct format and content.
+	 */
+	if (peer->ident_pkey == NULL)
+		return (XEVNT_ID);
+
+	if ((dsa = peer->ident_pkey->pkey->pkey.dsa) == NULL) {
+		msyslog(LOG_NOTICE, "crypto_alice3: defective key");
+		return (XEVNT_PUB);
+	}
+
+	/*
+	 * Roll new random r (0 < r < q).
+	 */
+	if (peer->iffval != NULL)
+		BN_free(peer->iffval);
+	peer->iffval = BN_new();
+	len = BN_num_bytes(dsa->p);
+	BN_rand(peer->iffval, len * 8, -1, 1);	/* r mod p */
+	bctx = BN_CTX_new();
+	BN_mod(peer->iffval, peer->iffval, dsa->p, bctx);
+	BN_CTX_free(bctx);
+
+	/*
+	 * Sign and send to Bob. The filestamp is from the local file.
+	 */
+	memset(vp, 0, sizeof(struct value));
+	tstamp = crypto_time();
+	vp->tstamp = htonl(tstamp);
+	vp->fstamp = htonl(peer->ident_pkey->fstamp);
+	vp->vallen = htonl(len);
+	vp->ptr = emalloc(len);
+	BN_bn2bin(peer->iffval, vp->ptr);
+	if (tstamp == 0)
+		return (XEVNT_OK);
+
+	vp->sig = emalloc(sign_siglen);
+	EVP_SignInit(&ctx, sign_digest);
+	EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
+	EVP_SignUpdate(&ctx, vp->ptr, len);
+	if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
+		vp->siglen = htonl(sign_siglen);
+	return (XEVNT_OK);
+}
+
+
+/*
+ * crypto_bob3 - construct Bob's response to Alice's challenge
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ERR	protocol error
+ */
+static int
+crypto_bob3(
+	struct exten *ep,	/* extension pointer */
+	struct value *vp	/* value pointer */
+	)
+{
+	DSA	*dsa;		/* MV parameters */
+	DSA	*sdsa;		/* DSA signature context fake */
+	BN_CTX	*bctx;		/* BIGNUM context */
+	EVP_MD_CTX ctx;		/* signature context */
+	tstamp_t tstamp;	/* NTP timestamp */
+	BIGNUM	*r, *k, *u;
+	u_char	*ptr;
+	u_int	len;
+
+	/*
+	 * If the MV parameters are not valid, something awful
+	 * happened or we are being tormented.
+	 */
+	if (mvkey_info == NULL) {
+		msyslog(LOG_NOTICE, "crypto_bob3: scheme unavailable");
+		return (XEVNT_ID);
+	}
+	dsa = mvkey_info->pkey->pkey.dsa;
+
+	/*
+	 * Extract r from the challenge.
+	 */
+	len = ntohl(ep->vallen);
+	if ((r = BN_bin2bn((u_char *)ep->pkt, len, NULL)) == NULL) {
+		msyslog(LOG_ERR, "crypto_bob3: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		return (XEVNT_ERR);
+	}
+
+	/*
+	 * Bob rolls random k (0 < k < q), making sure it is not a
+	 * factor of q. He then computes y = r A^k and sends (y, gbar^k,
+	 * and ghat^k) to Alice.
+	 */
+	bctx = BN_CTX_new(); k = BN_new(); u = BN_new();
+	sdsa = DSA_new();
+	sdsa->p = BN_new(); sdsa->q = BN_new(); sdsa->g = BN_new();
+	while (1) {
+		BN_rand(k, BN_num_bits(dsa->q), 0, 0);
+		BN_mod(k, k, dsa->q, bctx);
+		BN_gcd(u, k, dsa->q, bctx);
+		if (BN_is_one(u))
+			break;
+	}
+	BN_mod_exp(u, dsa->g, k, dsa->p, bctx); /* A^k r */
+	BN_mod_mul(sdsa->p, u, r, dsa->p, bctx);
+	BN_mod_exp(sdsa->q, dsa->priv_key, k, dsa->p, bctx); /* gbar */
+	BN_mod_exp(sdsa->g, dsa->pub_key, k, dsa->p, bctx); /* ghat */
+	BN_CTX_free(bctx); BN_free(k); BN_free(r); BN_free(u);
+#ifdef DEBUG
+	if (debug > 1)
+		DSA_print_fp(stdout, sdsa, 0);
+#endif
+
+	/*
+	 * Encode the values in ASN.1 and sign. The filestamp is from
+	 * the local file.
+	 */
+	memset(vp, 0, sizeof(struct value));
+	tstamp = crypto_time();
+	vp->tstamp = htonl(tstamp);
+	vp->fstamp = htonl(mvkey_info->fstamp);
+	len = i2d_DSAparams(sdsa, NULL);
+	if (len == 0) {
+		msyslog(LOG_ERR, "crypto_bob3: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		DSA_free(sdsa);
+		return (XEVNT_ERR);
+	}
+	vp->vallen = htonl(len);
+	ptr = emalloc(len);
+	vp->ptr = ptr;
+	i2d_DSAparams(sdsa, &ptr);
+	DSA_free(sdsa);
+	if (tstamp == 0)
+		return (XEVNT_OK);
+
+	vp->sig = emalloc(sign_siglen);
+	EVP_SignInit(&ctx, sign_digest);
+	EVP_SignUpdate(&ctx, (u_char *)&vp->tstamp, 12);
+	EVP_SignUpdate(&ctx, vp->ptr, len);
+	if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
+		vp->siglen = htonl(sign_siglen);
+	return (XEVNT_OK);
+}
+
+
+/*
+ * crypto_mv - verify Bob's response to Alice's challenge
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_ERR	protocol error
+ * XEVNT_FSP	bad filestamp
+ * XEVNT_ID	bad or missing group key
+ * XEVNT_PUB	bad or missing public key
+ */
+int
+crypto_mv(
+	struct exten *ep,	/* extension pointer */
+	struct peer *peer	/* peer structure pointer */
+	)
+{
+	DSA	*dsa;		/* MV parameters */
+	DSA	*sdsa;		/* DSA parameters */
+	BN_CTX	*bctx;		/* BIGNUM context */
+	BIGNUM	*k, *u, *v;
+	u_int	len;
+	const u_char *ptr;
+	int	temp;
+
+	/*
+	 * If the MV parameters are not valid or no challenge was sent,
+	 * something awful happened or we are being tormented.
+	 */
+	if (peer->ident_pkey == NULL) {
+		msyslog(LOG_NOTICE, "crypto_mv: scheme unavailable");
+		return (XEVNT_ID);
+	}
+	if (ntohl(ep->fstamp) != peer->ident_pkey->fstamp) {
+		msyslog(LOG_NOTICE, "crypto_mv: invalid filestamp %u",
+		    ntohl(ep->fstamp));
+		return (XEVNT_FSP);
+	}
+	if ((dsa = peer->ident_pkey->pkey->pkey.dsa) == NULL) {
+		msyslog(LOG_NOTICE, "crypto_mv: defective key");
+		return (XEVNT_PUB);
+	}
+	if (peer->iffval == NULL) {
+		msyslog(LOG_NOTICE, "crypto_mv: missing challenge");
+		return (XEVNT_ID);
+	}
+
+	/*
+	 * Extract the y, gbar and ghat values from the response.
+	 */
+	bctx = BN_CTX_new(); k = BN_new(); u = BN_new(); v = BN_new();
+	len = ntohl(ep->vallen);
+	ptr = (u_char *)ep->pkt;
+	if ((sdsa = d2i_DSAparams(NULL, &ptr, len)) == NULL) {
+		msyslog(LOG_ERR, "crypto_mv: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		return (XEVNT_ERR);
+	}
+
+	/*
+	 * Compute (gbar^xhat ghat^xbar) mod p.
+	 */
+	BN_mod_exp(u, sdsa->q, dsa->pub_key, dsa->p, bctx);
+	BN_mod_exp(v, sdsa->g, dsa->priv_key, dsa->p, bctx);
+	BN_mod_mul(u, u, v, dsa->p, bctx);
+	BN_mod_mul(u, u, sdsa->p, dsa->p, bctx);
+
+	/*
+	 * The result should match r.
+	 */
+	temp = BN_cmp(u, peer->iffval);
+	BN_CTX_free(bctx); BN_free(k); BN_free(u); BN_free(v);
+	BN_free(peer->iffval);
+	peer->iffval = NULL;
+	DSA_free(sdsa);
+	if (temp == 0)
+		return (XEVNT_OK);
+
+	msyslog(LOG_NOTICE, "crypto_mv: identity not verified");
+	return (XEVNT_ID);
+}
+
+
+/*
+ ***********************************************************************
+ *								       *
+ * The following routines are used to manipulate certificates          *
+ *								       *
+ ***********************************************************************
+ */
+/*
+ * cert_sign - sign x509 certificate equest and update value structure.
+ *
+ * The certificate request includes a copy of the host certificate,
+ * which includes the version number, subject name and public key of the
+ * host. The resulting certificate includes these values plus the
+ * serial number, issuer name and valid interval of the server. The
+ * valid interval extends from the current time to the same time one
+ * year hence. This may extend the life of the signed certificate beyond
+ * that of the signer certificate.
+ *
+ * It is convenient to use the NTP seconds of the current time as the
+ * serial number. In the value structure the timestamp is the current
+ * time and the filestamp is taken from the extension field. Note this
+ * routine is called only when the client clock is synchronized to a
+ * proventic source, so timestamp comparisons are valid.
+ *
+ * The host certificate is valid from the time it was generated for a
+ * period of one year. A signed certificate is valid from the time of
+ * signature for a period of one year, but only the host certificate (or
+ * sign certificate if used) is actually used to encrypt and decrypt
+ * signatures. The signature trail is built from the client via the
+ * intermediate servers to the trusted server. Each signature on the
+ * trail must be valid at the time of signature, but it could happen
+ * that a signer certificate expire before the signed certificate, which
+ * remains valid until its expiration. 
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_CRT	bad or missing certificate
+ * XEVNT_PER	host certificate expired
+ * XEVNT_PUB	bad or missing public key
+ * XEVNT_VFY	certificate not verified
+ */
+static int
+cert_sign(
+	struct exten *ep,	/* extension field pointer */
+	struct value *vp	/* value pointer */
+	)
+{
+	X509	*req;		/* X509 certificate request */
+	X509	*cert;		/* X509 certificate */
+	X509_EXTENSION *ext;	/* certificate extension */
+	ASN1_INTEGER *serial;	/* serial number */
+	X509_NAME *subj;	/* distinguished (common) name */
+	EVP_PKEY *pkey;		/* public key */
+	EVP_MD_CTX ctx;		/* message digest context */
+	tstamp_t tstamp;	/* NTP timestamp */
+	struct calendar tscal;
+	u_int	len;
+	const u_char *cptr;
+	u_char *ptr;
+	int	i, temp;
+
+	/*
+	 * Decode ASN.1 objects and construct certificate structure.
+	 * Make sure the system clock is synchronized to a proventic
+	 * source.
+	 */
+	tstamp = crypto_time();
+	if (tstamp == 0)
+		return (XEVNT_TSP);
+
+	cptr = (void *)ep->pkt;
+	if ((req = d2i_X509(NULL, &cptr, ntohl(ep->vallen))) == NULL) {
+		msyslog(LOG_ERR, "cert_sign: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		return (XEVNT_CRT);
+	}
+	/*
+	 * Extract public key and check for errors.
+	 */
+	if ((pkey = X509_get_pubkey(req)) == NULL) {
+		msyslog(LOG_ERR, "cert_sign: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		X509_free(req);
+		return (XEVNT_PUB);
+	}
+
+	/*
+	 * Generate X509 certificate signed by this server. If this is a
+	 * trusted host, the issuer name is the group name; otherwise,
+	 * it is the host name. Also copy any extensions that might be
+	 * present.
+	 */
+	cert = X509_new();
+	X509_set_version(cert, X509_get_version(req));
+	serial = ASN1_INTEGER_new();
+	ASN1_INTEGER_set(serial, tstamp);
+	X509_set_serialNumber(cert, serial);
+	X509_gmtime_adj(X509_get_notBefore(cert), 0L);
+	X509_gmtime_adj(X509_get_notAfter(cert), YEAR);
+	subj = X509_get_issuer_name(cert);
+	X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
+	    hostval.ptr, strlen(hostval.ptr), -1, 0);
+	subj = X509_get_subject_name(req);
+	X509_set_subject_name(cert, subj);
+	X509_set_pubkey(cert, pkey);
+	temp = X509_get_ext_count(req);
+	for (i = 0; i < temp; i++) {
+		ext = X509_get_ext(req, i);
+		INSIST(X509_add_ext(cert, ext, -1));
+	}
+	X509_free(req);
+
+	/*
+	 * Sign and verify the client certificate, but only if the host
+	 * certificate has not expired.
+	 */
+	(void)ntpcal_ntp_to_date(&tscal, tstamp, NULL);
+	if ((calcomp(&tscal, &(cert_host->first)) < 0)
+	|| (calcomp(&tscal, &(cert_host->last)) > 0)) {
+		X509_free(cert);
+		return (XEVNT_PER);
+	}
+	X509_sign(cert, sign_pkey, sign_digest);
+	if (X509_verify(cert, sign_pkey) <= 0) {
+		msyslog(LOG_ERR, "cert_sign: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		X509_free(cert);
+		return (XEVNT_VFY);
+	}
+	len = i2d_X509(cert, NULL);
+
+	/*
+	 * Build and sign the value structure. We have to sign it here,
+	 * since the response has to be returned right away. This is a
+	 * clogging hazard.
+	 */
+	memset(vp, 0, sizeof(struct value));
+	vp->tstamp = htonl(tstamp);
+	vp->fstamp = ep->fstamp;
+	vp->vallen = htonl(len);
+	vp->ptr = emalloc(len);
+	ptr = vp->ptr;
+	i2d_X509(cert, &ptr);
+	vp->siglen = 0;
+	if (tstamp != 0) {
+		vp->sig = emalloc(sign_siglen);
+		EVP_SignInit(&ctx, sign_digest);
+		EVP_SignUpdate(&ctx, (u_char *)vp, 12);
+		EVP_SignUpdate(&ctx, vp->ptr, len);
+		if (EVP_SignFinal(&ctx, vp->sig, &len, sign_pkey))
+			vp->siglen = htonl(sign_siglen);
+	}
+#ifdef DEBUG
+	if (debug > 1)
+		X509_print_fp(stdout, cert);
+#endif
+	X509_free(cert);
+	return (XEVNT_OK);
+}
+
+
+/*
+ * cert_install - install certificate in certificate cache
+ *
+ * This routine encodes an extension field into a certificate info/value
+ * structure. It searches the certificate list for duplicates and
+ * expunges whichever is older. Finally, it inserts this certificate
+ * first on the list.
+ *
+ * Returns certificate info pointer if valid, NULL if not.
+ */
+struct cert_info *
+cert_install(
+	struct exten *ep,	/* cert info/value */
+	struct peer *peer	/* peer structure */
+	)
+{
+	struct cert_info *cp, *xp, **zp;
+
+	/*
+	 * Parse and validate the signed certificate. If valid,
+	 * construct the info/value structure; otherwise, scamper home
+	 * empty handed.
+	 */
+	if ((cp = cert_parse((u_char *)ep->pkt, (long)ntohl(ep->vallen),
+	    (tstamp_t)ntohl(ep->fstamp))) == NULL)
+		return (NULL);
+
+	/*
+	 * Scan certificate list looking for another certificate with
+	 * the same subject and issuer. If another is found with the
+	 * same or older filestamp, unlink it and return the goodies to
+	 * the heap. If another is found with a later filestamp, discard
+	 * the new one and leave the building with the old one.
+	 *
+	 * Make a note to study this issue again. An earlier certificate
+	 * with a long lifetime might be overtaken by a later
+	 * certificate with a short lifetime, thus invalidating the
+	 * earlier signature. However, we gotta find a way to leak old
+	 * stuff from the cache, so we do it anyway. 
+	 */
+	zp = &cinfo;
+	for (xp = cinfo; xp != NULL; xp = xp->link) {
+		if (strcmp(cp->subject, xp->subject) == 0 &&
+		    strcmp(cp->issuer, xp->issuer) == 0) {
+			if (ntohl(cp->cert.fstamp) <=
+			    ntohl(xp->cert.fstamp)) {
+				cert_free(cp);
+				cp = xp;
+			} else {
+				*zp = xp->link;
+				cert_free(xp);
+				xp = NULL;
+			}
+			break;
+		}
+		zp = &xp->link;
+	}
+	if (xp == NULL) {
+		cp->link = cinfo;
+		cinfo = cp;
+	}
+	cp->flags |= CERT_VALID;
+	crypto_update();
+	return (cp);
+}
+
+
+/*
+ * cert_hike - verify the signature using the issuer public key
+ *
+ * Returns
+ * XEVNT_OK	success
+ * XEVNT_CRT	bad or missing certificate
+ * XEVNT_PER	host certificate expired
+ * XEVNT_VFY	certificate not verified
+ */
+int
+cert_hike(
+	struct peer *peer,	/* peer structure pointer */
+	struct cert_info *yp	/* issuer certificate */
+	)
+{
+	struct cert_info *xp;	/* subject certificate */
+	X509	*cert;		/* X509 certificate */
+	const u_char *ptr;
+
+	/*
+	 * Save the issuer on the new certificate, but remember the old
+	 * one.
+	 */
+	if (peer->issuer != NULL)
+		free(peer->issuer);
+	peer->issuer = estrdup(yp->issuer);
+	xp = peer->xinfo;
+	peer->xinfo = yp;
+
+	/*
+	 * If subject Y matches issuer Y, then the certificate trail is
+	 * complete. If Y is not trusted, the server certificate has yet
+	 * been signed, so keep trying. Otherwise, save the group key
+	 * and light the valid bit. If the host certificate is trusted,
+	 * do not execute a sign exchange. If no identity scheme is in
+	 * use, light the identity and proventic bits.
+	 */
+	if (strcmp(yp->subject, yp->issuer) == 0) {
+		if (!(yp->flags & CERT_TRUST))
+			return (XEVNT_OK);
+
+		/*
+		 * If the server has an an identity scheme, fetch the
+		 * identity credentials. If not, the identity is
+		 * verified only by the trusted certificate. The next
+		 * signature will set the server proventic.
+		 */
+		peer->crypto |= CRYPTO_FLAG_CERT;
+		peer->grpkey = yp->grpkey;
+		if (peer->ident == NULL || !(peer->crypto &
+		    CRYPTO_FLAG_MASK))
+			peer->crypto |= CRYPTO_FLAG_VRFY;
+	}
+
+	/*
+	 * If X exists, verify signature X using public key Y.
+	 */
+	if (xp == NULL)
+		return (XEVNT_OK);
+
+	ptr = (u_char *)xp->cert.ptr;
+	cert = d2i_X509(NULL, &ptr, ntohl(xp->cert.vallen));
+	if (cert == NULL) {
+		xp->flags |= CERT_ERROR;
+		return (XEVNT_CRT);
+	}
+	if (X509_verify(cert, yp->pkey) <= 0) {
+		X509_free(cert);
+		xp->flags |= CERT_ERROR;
+		return (XEVNT_VFY);
+	}
+	X509_free(cert);
+
+	/*
+	 * Signature X is valid only if it begins during the
+	 * lifetime of Y. 
+	 */
+	if ((calcomp(&(xp->first), &(yp->first)) < 0)
+	|| (calcomp(&(xp->first), &(yp->last)) > 0)) {
+		xp->flags |= CERT_ERROR;
+		return (XEVNT_PER);
+	}
+	xp->flags |= CERT_SIGN;
+	return (XEVNT_OK);
+}
+
+
+/*
+ * cert_parse - parse x509 certificate and create info/value structures.
+ *
+ * The server certificate includes the version number, issuer name,
+ * subject name, public key and valid date interval. If the issuer name
+ * is the same as the subject name, the certificate is self signed and
+ * valid only if the server is configured as trustable. If the names are
+ * different, another issuer has signed the server certificate and
+ * vouched for it. In this case the server certificate is valid if
+ * verified by the issuer public key.
+ *
+ * Returns certificate info/value pointer if valid, NULL if not.
+ */
+struct cert_info *		/* certificate information structure */
+cert_parse(
+	const u_char *asn1cert,	/* X509 certificate */
+	long	len,		/* certificate length */
+	tstamp_t fstamp		/* filestamp */
+	)
+{
+	X509	*cert;		/* X509 certificate */
+	X509_EXTENSION *ext;	/* X509v3 extension */
+	struct cert_info *ret;	/* certificate info/value */
+	BIO	*bp;
+	char	pathbuf[MAXFILENAME];
+	const u_char *ptr;
+	char	*pch;
+	int	temp, cnt, i;
+	struct calendar fscal;
+
+	/*
+	 * Decode ASN.1 objects and construct certificate structure.
+	 */
+	ptr = asn1cert;
+	if ((cert = d2i_X509(NULL, &ptr, len)) == NULL) {
+		msyslog(LOG_ERR, "cert_parse: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		return (NULL);
+	}
+#ifdef DEBUG
+	if (debug > 1)
+		X509_print_fp(stdout, cert);
+#endif
+
+	/*
+	 * Extract version, subject name and public key.
+	 */
+	ret = emalloc_zero(sizeof(*ret));
+	if ((ret->pkey = X509_get_pubkey(cert)) == NULL) {
+		msyslog(LOG_ERR, "cert_parse: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		cert_free(ret);
+		X509_free(cert);
+		return (NULL);
+	}
+	ret->version = X509_get_version(cert);
+	X509_NAME_oneline(X509_get_subject_name(cert), pathbuf,
+	    sizeof(pathbuf));
+	pch = strstr(pathbuf, "CN=");
+	if (NULL == pch) {
+		msyslog(LOG_NOTICE, "cert_parse: invalid subject %s",
+		    pathbuf);
+		cert_free(ret);
+		X509_free(cert);
+		return (NULL);
+	}
+	ret->subject = estrdup(pch + 3);
+
+	/*
+	 * Extract remaining objects. Note that the NTP serial number is
+	 * the NTP seconds at the time of signing, but this might not be
+	 * the case for other authority. We don't bother to check the
+	 * objects at this time, since the real crunch can happen only
+	 * when the time is valid but not yet certificated.
+	 */
+	ret->nid = OBJ_obj2nid(cert->cert_info->signature->algorithm);
+	ret->digest = (const EVP_MD *)EVP_get_digestbynid(ret->nid);
+	ret->serial =
+	    (u_long)ASN1_INTEGER_get(X509_get_serialNumber(cert));
+	X509_NAME_oneline(X509_get_issuer_name(cert), pathbuf,
+	    sizeof(pathbuf));
+	if ((pch = strstr(pathbuf, "CN=")) == NULL) {
+		msyslog(LOG_NOTICE, "cert_parse: invalid issuer %s",
+		    pathbuf);
+		cert_free(ret);
+		X509_free(cert);
+		return (NULL);
+	}
+	ret->issuer = estrdup(pch + 3);
+	asn_to_calendar(X509_get_notBefore(cert), &(ret->first));
+	asn_to_calendar(X509_get_notAfter(cert), &(ret->last));
+
+	/*
+	 * Extract extension fields. These are ad hoc ripoffs of
+	 * currently assigned functions and will certainly be changed
+	 * before prime time.
+	 */
+	cnt = X509_get_ext_count(cert);
+	for (i = 0; i < cnt; i++) {
+		ext = X509_get_ext(cert, i);
+		temp = OBJ_obj2nid(ext->object);
+		switch (temp) {
+
+		/*
+		 * If a key_usage field is present, we decode whether
+		 * this is a trusted or private certificate. This is
+		 * dorky; all we want is to compare NIDs, but OpenSSL
+		 * insists on BIO text strings.
+		 */
+		case NID_ext_key_usage:
+			bp = BIO_new(BIO_s_mem());
+			X509V3_EXT_print(bp, ext, 0, 0);
+			BIO_gets(bp, pathbuf, sizeof(pathbuf));
+			BIO_free(bp);
+			if (strcmp(pathbuf, "Trust Root") == 0)
+				ret->flags |= CERT_TRUST;
+			else if (strcmp(pathbuf, "Private") == 0)
+				ret->flags |= CERT_PRIV;
+#if DEBUG
+			if (debug)
+				printf("cert_parse: %s: %s\n",
+				    OBJ_nid2ln(temp), pathbuf);
+#endif
+			break;
+
+		/*
+		 * If a NID_subject_key_identifier field is present, it
+		 * contains the GQ public key.
+		 */
+		case NID_subject_key_identifier:
+			ret->grpkey = BN_bin2bn(&ext->value->data[2],
+			    ext->value->length - 2, NULL);
+			/* fall through */
+#if DEBUG
+		default:
+			if (debug)
+				printf("cert_parse: %s\n",
+				    OBJ_nid2ln(temp));
+#endif
+		}
+	}
+	if (strcmp(ret->subject, ret->issuer) == 0) {
+
+		/*
+		 * If certificate is self signed, verify signature.
+		 */
+		if (X509_verify(cert, ret->pkey) <= 0) {
+			msyslog(LOG_NOTICE,
+			    "cert_parse: signature not verified %s",
+			    ret->subject);
+			cert_free(ret);
+			X509_free(cert);
+			return (NULL);
+		}
+	} else {
+
+		/*
+		 * Check for a certificate loop.
+		 */
+		if (strcmp(hostval.ptr, ret->issuer) == 0) {
+			msyslog(LOG_NOTICE,
+			    "cert_parse: certificate trail loop %s",
+			    ret->subject);
+			cert_free(ret);
+			X509_free(cert);
+			return (NULL);
+		}
+	}
+
+	/*
+	 * Verify certificate valid times. Note that certificates cannot
+	 * be retroactive.
+	 */
+	(void)ntpcal_ntp_to_date(&fscal, fstamp, NULL);
+	if ((calcomp(&(ret->first), &(ret->last)) > 0)
+	|| (calcomp(&(ret->first), &fscal) < 0)) {
+		msyslog(LOG_NOTICE,
+		    "cert_parse: invalid times %s first %u-%02u-%02uT%02u:%02u:%02u last %u-%02u-%02uT%02u:%02u:%02u fstamp %u-%02u-%02uT%02u:%02u:%02u",
+		    ret->subject,
+		    ret->first.year, ret->first.month, ret->first.monthday,
+		    ret->first.hour, ret->first.minute, ret->first.second,
+		    ret->last.year, ret->last.month, ret->last.monthday,
+		    ret->last.hour, ret->last.minute, ret->last.second,
+		    fscal.year, fscal.month, fscal.monthday,
+		    fscal.hour, fscal.minute, fscal.second);
+		cert_free(ret);
+		X509_free(cert);
+		return (NULL);
+	}
+
+	/*
+	 * Build the value structure to sign and send later.
+	 */
+	ret->cert.fstamp = htonl(fstamp);
+	ret->cert.vallen = htonl(len);
+	ret->cert.ptr = emalloc(len);
+	memcpy(ret->cert.ptr, asn1cert, len);
+	X509_free(cert);
+	return (ret);
+}
+
+
+/*
+ * cert_free - free certificate information structure
+ */
+void
+cert_free(
+	struct cert_info *cinf	/* certificate info/value structure */ 
+	)
+{
+	if (cinf->pkey != NULL)
+		EVP_PKEY_free(cinf->pkey);
+	if (cinf->subject != NULL)
+		free(cinf->subject);
+	if (cinf->issuer != NULL)
+		free(cinf->issuer);
+	if (cinf->grpkey != NULL)
+		BN_free(cinf->grpkey);
+	value_free(&cinf->cert);
+	free(cinf);
+}
+
+
+/*
+ * crypto_key - load cryptographic parameters and keys
+ *
+ * This routine searches the key cache for matching name in the form
+ * ntpkey_<key>_<name>, where <key> is one of host, sign, iff, gq, mv,
+ * and <name> is the host/group name. If not found, it tries to load a
+ * PEM-encoded file of the same name and extracts the filestamp from
+ * the first line of the file name. It returns the key pointer if valid,
+ * NULL if not.
+ */
+static struct pkey_info *
+crypto_key(
+	char	*cp,		/* file name */
+	char	*passwd1,	/* password */
+	sockaddr_u *addr 	/* IP address */
+	)
+{
+	FILE	*str;		/* file handle */
+	struct pkey_info *pkp;	/* generic key */
+	EVP_PKEY *pkey = NULL;	/* public/private key */
+	tstamp_t fstamp;
+	char	filename[MAXFILENAME]; /* name of key file */
+	char	linkname[MAXFILENAME]; /* filestamp buffer) */
+	char	statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
+	char	*ptr;
+
+	/*
+	 * Search the key cache for matching key and name.
+	 */
+	for (pkp = pkinfo; pkp != NULL; pkp = pkp->link) {
+		if (strcmp(cp, pkp->name) == 0)
+			return (pkp);
+	}  
+
+	/*
+	 * Open the key file. If the first character of the file name is
+	 * not '/', prepend the keys directory string. If something goes
+	 * wrong, abandon ship.
+	 */
+	if (*cp == '/')
+		strlcpy(filename, cp, sizeof(filename));
+	else
+		snprintf(filename, sizeof(filename), "%s/%s", keysdir,
+		    cp);
+	str = fopen(filename, "r");
+	if (str == NULL)
+		return (NULL);
+
+	/*
+	 * Read the filestamp, which is contained in the first line.
+	 */
+	if ((ptr = fgets(linkname, sizeof(linkname), str)) == NULL) {
+		msyslog(LOG_ERR, "crypto_key: empty file %s",
+		    filename);
+		fclose(str);
+		return (NULL);
+	}
+	if ((ptr = strrchr(ptr, '.')) == NULL) {
+		msyslog(LOG_ERR, "crypto_key: no filestamp %s",
+		    filename);
+		fclose(str);
+		return (NULL);
+	}
+	if (sscanf(++ptr, "%u", &fstamp) != 1) {
+		msyslog(LOG_ERR, "crypto_key: invalid filestamp %s",
+		    filename);
+		fclose(str);
+		return (NULL);
+	}
+
+	/*
+	 * Read and decrypt PEM-encoded private key. If it fails to
+	 * decrypt, game over.
+	 */
+	pkey = PEM_read_PrivateKey(str, NULL, NULL, passwd1);
+	fclose(str);
+	if (pkey == NULL) {
+		msyslog(LOG_ERR, "crypto_key: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		exit (-1);
+	}
+
+	/*
+	 * Make a new entry in the key cache.
+	 */
+	pkp = emalloc(sizeof(struct pkey_info));
+	pkp->link = pkinfo;
+	pkinfo = pkp;
+	pkp->pkey = pkey;
+	pkp->name = estrdup(cp);
+	pkp->fstamp = fstamp;
+
+	/*
+	 * Leave tracks in the cryptostats.
+	 */
+	if ((ptr = strrchr(linkname, '\n')) != NULL)
+		*ptr = '\0'; 
+	snprintf(statstr, sizeof(statstr), "%s mod %d", &linkname[2],
+	    EVP_PKEY_size(pkey) * 8);
+	record_crypto_stats(addr, statstr);
+#ifdef DEBUG
+	if (debug)
+		printf("crypto_key: %s\n", statstr);
+	if (debug > 1) {
+		if (pkey->type == EVP_PKEY_DSA)
+			DSA_print_fp(stdout, pkey->pkey.dsa, 0);
+		else if (pkey->type == EVP_PKEY_RSA)
+			RSA_print_fp(stdout, pkey->pkey.rsa, 0);
+	}
+#endif
+	return (pkp);
+}
+
+
+/*
+ ***********************************************************************
+ *								       *
+ * The following routines are used only at initialization time         *
+ *								       *
+ ***********************************************************************
+ */
+/*
+ * crypto_cert - load certificate from file
+ *
+ * This routine loads an X.509 RSA or DSA certificate from a file and
+ * constructs a info/cert value structure for this machine. The
+ * structure includes a filestamp extracted from the file name. Later
+ * the certificate can be sent to another machine on request.
+ *
+ * Returns certificate info/value pointer if valid, NULL if not.
+ */
+static struct cert_info *	/* certificate information */
+crypto_cert(
+	char	*cp		/* file name */
+	)
+{
+	struct cert_info *ret; /* certificate information */
+	FILE	*str;		/* file handle */
+	char	filename[MAXFILENAME]; /* name of certificate file */
+	char	linkname[MAXFILENAME]; /* filestamp buffer */
+	char	statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
+	tstamp_t fstamp;	/* filestamp */
+	long	len;
+	char	*ptr;
+	char	*name, *header;
+	u_char	*data;
+
+	/*
+	 * Open the certificate file. If the first character of the file
+	 * name is not '/', prepend the keys directory string. If
+	 * something goes wrong, abandon ship.
+	 */
+	if (*cp == '/')
+		strlcpy(filename, cp, sizeof(filename));
+	else
+		snprintf(filename, sizeof(filename), "%s/%s", keysdir,
+		    cp);
+	str = fopen(filename, "r");
+	if (str == NULL)
+		return (NULL);
+
+	/*
+	 * Read the filestamp, which is contained in the first line.
+	 */
+	if ((ptr = fgets(linkname, sizeof(linkname), str)) == NULL) {
+		msyslog(LOG_ERR, "crypto_cert: empty file %s",
+		    filename);
+		fclose(str);
+		return (NULL);
+	}
+	if ((ptr = strrchr(ptr, '.')) == NULL) {
+		msyslog(LOG_ERR, "crypto_cert: no filestamp %s",
+		    filename);
+		fclose(str);
+		return (NULL);
+	}
+	if (sscanf(++ptr, "%u", &fstamp) != 1) {
+		msyslog(LOG_ERR, "crypto_cert: invalid filestamp %s",
+		    filename);
+		fclose(str);
+		return (NULL);
+	}
+
+	/*
+	 * Read PEM-encoded certificate and install.
+	 */
+	if (!PEM_read(str, &name, &header, &data, &len)) {
+		msyslog(LOG_ERR, "crypto_cert: %s",
+		    ERR_error_string(ERR_get_error(), NULL));
+		fclose(str);
+		return (NULL);
+	}
+	fclose(str);
+	free(header);
+	if (strcmp(name, "CERTIFICATE") != 0) {
+		msyslog(LOG_NOTICE, "crypto_cert: wrong PEM type %s",
+		    name);
+		free(name);
+		free(data);
+		return (NULL);
+	}
+	free(name);
+
+	/*
+	 * Parse certificate and generate info/value structure. The
+	 * pointer and copy nonsense is due something broken in Solaris.
+	 */
+	ret = cert_parse(data, len, fstamp);
+	free(data);
+	if (ret == NULL)
+		return (NULL);
+
+	if ((ptr = strrchr(linkname, '\n')) != NULL)
+		*ptr = '\0'; 
+	snprintf(statstr, sizeof(statstr), "%s 0x%x len %lu",
+	    &linkname[2], ret->flags, len);
+	record_crypto_stats(NULL, statstr);
+#ifdef DEBUG
+	if (debug)
+		printf("crypto_cert: %s\n", statstr);
+#endif
+	return (ret);
+}
+
+
+/*
+ * crypto_setup - load keys, certificate and identity parameters
+ *
+ * This routine loads the public/private host key and certificate. If
+ * available, it loads the public/private sign key, which defaults to
+ * the host key. The host key must be RSA, but the sign key can be
+ * either RSA or DSA. If a trusted certificate, it loads the identity
+ * parameters. In either case, the public key on the certificate must
+ * agree with the sign key.
+ *
+ * Required but missing files and inconsistent data and errors are
+ * fatal. Allowing configuration to continue would be hazardous and
+ * require really messy error checks.
+ */
+void
+crypto_setup(void)
+{
+	struct pkey_info *pinfo; /* private/public key */
+	char	filename[MAXFILENAME]; /* file name buffer */
+	char	hostname[MAXFILENAME]; /* host name buffer */
+	char	*randfile;
+	char	statstr[NTP_MAXSTRLEN]; /* statistics for filegen */
+	l_fp	seed;		/* crypto PRNG seed as NTP timestamp */
+	u_int	len;
+	int	bytes;
+	u_char	*ptr;
+
+	/*
+	 * Check for correct OpenSSL version and avoid initialization in
+	 * the case of multiple crypto commands.
+	 */
+	if (crypto_flags & CRYPTO_FLAG_ENAB) {
+		msyslog(LOG_NOTICE,
+		    "crypto_setup: spurious crypto command");
+		return;
+	}
+	ssl_check_version();
+
+	/*
+	 * Load required random seed file and seed the random number
+	 * generator. Be default, it is found as .rnd in the user home
+	 * directory. The root home directory may be / or /root,
+	 * depending on the system. Wiggle the contents a bit and write
+	 * it back so the sequence does not repeat when we next restart.
+	 */
+	if (!RAND_status()) {
+		if (rand_file == NULL) {
+			RAND_file_name(filename, sizeof(filename));
+			randfile = filename;
+		} else if (*rand_file != '/') {
+			snprintf(filename, sizeof(filename), "%s/%s",
+			    keysdir, rand_file);
+			randfile = filename;
+		} else
+			randfile = rand_file;
+
+		if ((bytes = RAND_load_file(randfile, -1)) == 0) {
+			msyslog(LOG_ERR,
+			    "crypto_setup: random seed file %s missing",
+			    randfile);
+			exit (-1);
+		}
+		get_systime(&seed);
+		RAND_seed(&seed, sizeof(l_fp));
+		RAND_write_file(randfile);
+#ifdef DEBUG
+		if (debug)
+			printf(
+			    "crypto_setup: OpenSSL version %lx random seed file %s bytes read %d\n",
+			    SSLeay(), randfile, bytes);
+#endif
+	}
+
+	/*
+	 * Initialize structures.
+	 */
+	gethostname(hostname, sizeof(hostname));
+	if (host_filename != NULL)
+		strlcpy(hostname, host_filename, sizeof(hostname));
+	if (passwd == NULL)
+		passwd = estrdup(hostname);
+	memset(&hostval, 0, sizeof(hostval));
+	memset(&pubkey, 0, sizeof(pubkey));
+	memset(&tai_leap, 0, sizeof(tai_leap));
+
+	/*
+	 * Load required host key from file "ntpkey_host_<hostname>". If
+	 * no host key file is not found or has invalid password, life
+	 * as we know it ends. The host key also becomes the default
+	 * sign key. 
+	 */
+	snprintf(filename, sizeof(filename), "ntpkey_host_%s", hostname);
+	pinfo = crypto_key(filename, passwd, NULL);
+	if (pinfo == NULL) {
+		msyslog(LOG_ERR,
+		    "crypto_setup: host key file %s not found or corrupt",
+		    filename);
+		exit (-1);
+	}
+	if (pinfo->pkey->type != EVP_PKEY_RSA) {
+		msyslog(LOG_ERR,
+		    "crypto_setup: host key is not RSA key type");
+		exit (-1);
+	}
+	host_pkey = pinfo->pkey;
+	sign_pkey = host_pkey;
+	hostval.fstamp = htonl(pinfo->fstamp);
+	
+	/*
+	 * Construct public key extension field for agreement scheme.
+	 */
+	len = i2d_PublicKey(host_pkey, NULL);
+	ptr = emalloc(len);
+	pubkey.ptr = ptr;
+	i2d_PublicKey(host_pkey, &ptr);
+	pubkey.fstamp = hostval.fstamp;
+	pubkey.vallen = htonl(len);
+
+	/*
+	 * Load optional sign key from file "ntpkey_sign_<hostname>". If
+	 * available, it becomes the sign key.
+	 */
+	snprintf(filename, sizeof(filename), "ntpkey_sign_%s", hostname);
+	pinfo = crypto_key(filename, passwd, NULL);
+	if (pinfo != NULL)
+		sign_pkey = pinfo->pkey;
+
+	/*
+	 * Load required certificate from file "ntpkey_cert_<hostname>".
+	 */
+	snprintf(filename, sizeof(filename), "ntpkey_cert_%s", hostname);
+	cinfo = crypto_cert(filename);
+	if (cinfo == NULL) {
+		msyslog(LOG_ERR,
+		    "crypto_setup: certificate file %s not found or corrupt",
+		    filename);
+		exit (-1);
+	}
+	cert_host = cinfo;
+	sign_digest = cinfo->digest;
+	sign_siglen = EVP_PKEY_size(sign_pkey);
+	if (cinfo->flags & CERT_PRIV)
+		crypto_flags |= CRYPTO_FLAG_PRIV;
+
+	/*
+	 * The certificate must be self-signed.
+	 */
+	if (strcmp(cinfo->subject, cinfo->issuer) != 0) {
+		msyslog(LOG_ERR,
+		    "crypto_setup: certificate %s is not self-signed",
+		    filename);
+		exit (-1);
+	}
+	hostval.ptr = estrdup(cinfo->subject);
+	hostval.vallen = htonl(strlen(cinfo->subject));
+	sys_hostname = hostval.ptr;
+	ptr = (u_char *)strchr(sys_hostname, '@');
+	if (ptr != NULL)
+		sys_groupname = estrdup((char *)++ptr);
+	if (ident_filename != NULL)
+		strlcpy(hostname, ident_filename, sizeof(hostname));
+
+	/*
+	 * Load optional IFF parameters from file
+	 * "ntpkey_iffkey_<hostname>".
+	 */
+	snprintf(filename, sizeof(filename), "ntpkey_iffkey_%s",
+	    hostname);
+	iffkey_info = crypto_key(filename, passwd, NULL);
+	if (iffkey_info != NULL)
+		crypto_flags |= CRYPTO_FLAG_IFF;
+
+	/*
+	 * Load optional GQ parameters from file
+	 * "ntpkey_gqkey_<hostname>".
+	 */
+	snprintf(filename, sizeof(filename), "ntpkey_gqkey_%s",
+	    hostname);
+	gqkey_info = crypto_key(filename, passwd, NULL);
+	if (gqkey_info != NULL)
+		crypto_flags |= CRYPTO_FLAG_GQ;
+
+	/*
+	 * Load optional MV parameters from file
+	 * "ntpkey_mvkey_<hostname>".
+	 */
+	snprintf(filename, sizeof(filename), "ntpkey_mvkey_%s",
+	    hostname);
+	mvkey_info = crypto_key(filename, passwd, NULL);
+	if (mvkey_info != NULL)
+		crypto_flags |= CRYPTO_FLAG_MV;
+
+	/*
+	 * We met the enemy and he is us. Now strike up the dance.
+	 */
+	crypto_flags |= CRYPTO_FLAG_ENAB | (cinfo->nid << 16);
+	snprintf(statstr, sizeof(statstr), "setup 0x%x host %s %s",
+	    crypto_flags, hostname, OBJ_nid2ln(cinfo->nid));
+	record_crypto_stats(NULL, statstr);
+#ifdef DEBUG
+	if (debug)
+		printf("crypto_setup: %s\n", statstr);
+#endif
+}
+
+
+/*
+ * crypto_config - configure data from the crypto command.
+ */
+void
+crypto_config(
+	int	item,		/* configuration item */
+	char	*cp		/* item name */
+	)
+{
+	int	nid;
+
+#ifdef DEBUG
+	if (debug > 1)
+		printf("crypto_config: item %d %s\n", item, cp);
+#endif
+	switch (item) {
+
+	/*
+	 * Set host name (host).
+	 */
+	case CRYPTO_CONF_PRIV:
+		if (NULL != host_filename)
+			free(host_filename);
+		host_filename = estrdup(cp);
+		break;
+
+	/*
+	 * Set group name (ident).
+	 */
+	case CRYPTO_CONF_IDENT:
+		if (NULL != ident_filename)
+			free(ident_filename);
+		ident_filename = estrdup(cp);
+		break;
+
+	/*
+	 * Set private key password (pw).
+	 */
+	case CRYPTO_CONF_PW:
+		if (NULL != passwd)
+			free(passwd);
+		passwd = estrdup(cp);
+		break;
+
+	/*
+	 * Set random seed file name (randfile).
+	 */
+	case CRYPTO_CONF_RAND:
+		if (NULL != rand_file)
+			free(rand_file);
+		rand_file = estrdup(cp);
+		break;
+
+	/*
+	 * Set message digest NID.
+	 */
+	case CRYPTO_CONF_NID:
+		nid = OBJ_sn2nid(cp);
+		if (nid == 0)
+			msyslog(LOG_ERR,
+			    "crypto_config: invalid digest name %s", cp);
+		else
+			crypto_nid = nid;
+		break;
+	}
+}
+# else	/* !AUTOKEY follows */
+int ntp_crypto_bs_pubkey;
+# endif	/* !AUTOKEY */