summaryrefslogtreecommitdiff
path: root/src/pk/dh/dh_sys.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/pk/dh/dh_sys.c')
-rw-r--r--src/pk/dh/dh_sys.c499
1 files changed, 0 insertions, 499 deletions
diff --git a/src/pk/dh/dh_sys.c b/src/pk/dh/dh_sys.c
deleted file mode 100644
index 4f10556..0000000
--- a/src/pk/dh/dh_sys.c
+++ /dev/null
@@ -1,499 +0,0 @@
-/* LibTomCrypt, modular cryptographic library -- Tom St Denis
- *
- * LibTomCrypt is a library that provides various cryptographic
- * algorithms in a highly modular and flexible manner.
- *
- * The library is free for all purposes without any express
- * guarantee it works.
- *
- * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.org
- */
-
-/**
- @file dh_sys.c
- DH Crypto, Tom St Denis
-*/
-
-/**
- Encrypt a short symmetric key with a public DH key
- @param in The symmetric key to encrypt
- @param inlen The length of the key (octets)
- @param out [out] The ciphertext
- @param outlen [in/out] The max size and resulting size of the ciphertext
- @param prng An active PRNG state
- @param wprng The index of the PRNG desired
- @param hash The index of the hash desired (must produce a digest of size >= the size of the plaintext)
- @param key The public key you wish to encrypt with.
- @return CRYPT_OK if successful
-*/
-int dh_encrypt_key(const unsigned char *in, unsigned long inlen,
- unsigned char *out, unsigned long *outlen,
- prng_state *prng, int wprng, int hash,
- dh_key *key)
-{
- unsigned char *pub_expt, *dh_shared, *skey;
- dh_key pubkey;
- unsigned long x, y, z, hashsize, pubkeysize;
- int err;
-
- LTC_ARGCHK(in != NULL);
- LTC_ARGCHK(out != NULL);
- LTC_ARGCHK(outlen != NULL);
- LTC_ARGCHK(key != NULL);
-
- /* check that wprng/hash are not invalid */
- if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
- return err;
- }
-
- if ((err = hash_is_valid(hash)) != CRYPT_OK) {
- return err;
- }
-
- if (inlen > hash_descriptor[hash].hashsize) {
- return CRYPT_INVALID_HASH;
- }
-
- /* allocate memory */
- pub_expt = XMALLOC(DH_BUF_SIZE);
- dh_shared = XMALLOC(DH_BUF_SIZE);
- skey = XMALLOC(MAXBLOCKSIZE);
- if (pub_expt == NULL || dh_shared == NULL || skey == NULL) {
- if (pub_expt != NULL) {
- XFREE(pub_expt);
- }
- if (dh_shared != NULL) {
- XFREE(dh_shared);
- }
- if (skey != NULL) {
- XFREE(skey);
- }
- return CRYPT_MEM;
- }
-
- /* make a random key and export the public copy */
- if ((err = dh_make_key(prng, wprng, dh_get_size(key), &pubkey)) != CRYPT_OK) {
- goto LBL_ERR;
- }
-
- pubkeysize = DH_BUF_SIZE;
- if ((err = dh_export(pub_expt, &pubkeysize, PK_PUBLIC, &pubkey)) != CRYPT_OK) {
- dh_free(&pubkey);
- goto LBL_ERR;
- }
-
- /* now check if the out buffer is big enough */
- if (*outlen < (1 + 4 + 4 + PACKET_SIZE + pubkeysize + inlen)) {
- dh_free(&pubkey);
- err = CRYPT_BUFFER_OVERFLOW;
- goto LBL_ERR;
- }
-
- /* make random key */
- hashsize = hash_descriptor[hash].hashsize;
-
- x = DH_BUF_SIZE;
- if ((err = dh_shared_secret(&pubkey, key, dh_shared, &x)) != CRYPT_OK) {
- dh_free(&pubkey);
- goto LBL_ERR;
- }
- dh_free(&pubkey);
-
- z = MAXBLOCKSIZE;
- if ((err = hash_memory(hash, dh_shared, x, skey, &z)) != CRYPT_OK) {
- goto LBL_ERR;
- }
-
- /* store header */
- packet_store_header(out, PACKET_SECT_DH, PACKET_SUB_ENC_KEY);
-
- /* output header */
- y = PACKET_SIZE;
-
- /* size of hash name and the name itself */
- out[y++] = hash_descriptor[hash].ID;
-
- /* length of DH pubkey and the key itself */
- STORE32L(pubkeysize, out+y);
- y += 4;
- for (x = 0; x < pubkeysize; x++, y++) {
- out[y] = pub_expt[x];
- }
-
- /* Store the encrypted key */
- STORE32L(inlen, out+y);
- y += 4;
-
- for (x = 0; x < inlen; x++, y++) {
- out[y] = skey[x] ^ in[x];
- }
- *outlen = y;
-
- err = CRYPT_OK;
-LBL_ERR:
-#ifdef LTC_CLEAN_STACK
- /* clean up */
- zeromem(pub_expt, DH_BUF_SIZE);
- zeromem(dh_shared, DH_BUF_SIZE);
- zeromem(skey, MAXBLOCKSIZE);
-#endif
- XFREE(skey);
- XFREE(dh_shared);
- XFREE(pub_expt);
-
- return err;
-}
-
-/**
- Decrypt a DH encrypted symmetric key
- @param in The DH encrypted packet
- @param inlen The length of the DH encrypted packet
- @param out The plaintext
- @param outlen [in/out] The max size and resulting size of the plaintext
- @param key The private DH key corresponding to the public key that encrypted the plaintext
- @return CRYPT_OK if successful
-*/
-int dh_decrypt_key(const unsigned char *in, unsigned long inlen,
- unsigned char *out, unsigned long *outlen,
- dh_key *key)
-{
- unsigned char *shared_secret, *skey;
- unsigned long x, y, z, hashsize, keysize;
- int hash, err;
- dh_key pubkey;
-
- LTC_ARGCHK(in != NULL);
- LTC_ARGCHK(out != NULL);
- LTC_ARGCHK(outlen != NULL);
- LTC_ARGCHK(key != NULL);
-
- /* right key type? */
- if (key->type != PK_PRIVATE) {
- return CRYPT_PK_NOT_PRIVATE;
- }
-
- /* allocate ram */
- shared_secret = XMALLOC(DH_BUF_SIZE);
- skey = XMALLOC(MAXBLOCKSIZE);
- if (shared_secret == NULL || skey == NULL) {
- if (shared_secret != NULL) {
- XFREE(shared_secret);
- }
- if (skey != NULL) {
- XFREE(skey);
- }
- return CRYPT_MEM;
- }
-
- /* check if initial header should fit */
- if (inlen < PACKET_SIZE+1+4+4) {
- err = CRYPT_INVALID_PACKET;
- goto LBL_ERR;
- } else {
- inlen -= PACKET_SIZE+1+4+4;
- }
-
- /* is header correct? */
- if ((err = packet_valid_header((unsigned char *)in, PACKET_SECT_DH, PACKET_SUB_ENC_KEY)) != CRYPT_OK) {
- goto LBL_ERR;
- }
-
- /* now lets get the hash name */
- y = PACKET_SIZE;
- hash = find_hash_id(in[y++]);
- if (hash == -1) {
- err = CRYPT_INVALID_HASH;
- goto LBL_ERR;
- }
-
- /* common values */
- hashsize = hash_descriptor[hash].hashsize;
-
- /* get public key */
- LOAD32L(x, in+y);
-
- /* now check if the imported key will fit */
- if (inlen < x) {
- err = CRYPT_INVALID_PACKET;
- goto LBL_ERR;
- } else {
- inlen -= x;
- }
-
- y += 4;
- if ((err = dh_import(in+y, x, &pubkey)) != CRYPT_OK) {
- goto LBL_ERR;
- }
- y += x;
-
- /* make shared key */
- x = DH_BUF_SIZE;
- if ((err = dh_shared_secret(key, &pubkey, shared_secret, &x)) != CRYPT_OK) {
- dh_free(&pubkey);
- goto LBL_ERR;
- }
- dh_free(&pubkey);
-
- z = MAXBLOCKSIZE;
- if ((err = hash_memory(hash, shared_secret, x, skey, &z)) != CRYPT_OK) {
- goto LBL_ERR;
- }
-
- /* load in the encrypted key */
- LOAD32L(keysize, in+y);
-
- /* will the out fit as part of the input */
- if (inlen < keysize) {
- err = CRYPT_INVALID_PACKET;
- goto LBL_ERR;
- } else {
- inlen -= keysize;
- }
-
- if (keysize > *outlen) {
- err = CRYPT_BUFFER_OVERFLOW;
- goto LBL_ERR;
- }
- y += 4;
-
- *outlen = keysize;
-
- for (x = 0; x < keysize; x++, y++) {
- out[x] = skey[x] ^ in[y];
- }
-
- err = CRYPT_OK;
-LBL_ERR:
-#ifdef LTC_CLEAN_STACK
- zeromem(shared_secret, DH_BUF_SIZE);
- zeromem(skey, MAXBLOCKSIZE);
-#endif
-
- XFREE(skey);
- XFREE(shared_secret);
-
- return err;
-}
-
-/* perform an ElGamal Signature of a hash
- *
- * The math works as follows. x is the private key, M is the message to sign
-
- 1. pick a random k
- 2. compute a = g^k mod p
- 3. compute b = (M - xa)/k mod p
- 4. Send (a,b)
-
- Now to verify with y=g^x mod p, a and b
-
- 1. compute y^a * a^b = g^(xa) * g^(k*(M-xa)/k)
- = g^(xa + (M - xa))
- = g^M [all mod p]
-
- 2. Compare against g^M mod p [based on input hash].
- 3. If result of #2 == result of #1 then signature valid
-*/
-
-/**
- Sign a message digest using a DH private key
- @param in The data to sign
- @param inlen The length of the input (octets)
- @param out [out] The destination of the signature
- @param outlen [in/out] The max size and resulting size of the output
- @param prng An active PRNG state
- @param wprng The index of the PRNG desired
- @param key A private DH key
- @return CRYPT_OK if successful
-*/
-int dh_sign_hash(const unsigned char *in, unsigned long inlen,
- unsigned char *out, unsigned long *outlen,
- prng_state *prng, int wprng, dh_key *key)
-{
- mp_int a, b, k, m, g, p, p1, tmp;
- unsigned char *buf;
- unsigned long x, y;
- int err;
-
- LTC_ARGCHK(in != NULL);
- LTC_ARGCHK(out != NULL);
- LTC_ARGCHK(outlen != NULL);
- LTC_ARGCHK(key != NULL);
-
- /* check parameters */
- if (key->type != PK_PRIVATE) {
- return CRYPT_PK_NOT_PRIVATE;
- }
-
- if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
- return err;
- }
-
- /* is the IDX valid ? */
- if (is_valid_idx(key->idx) != 1) {
- return CRYPT_PK_INVALID_TYPE;
- }
-
- /* allocate ram for buf */
- buf = XMALLOC(520);
-
- /* make up a random value k,
- * since the order of the group is prime
- * we need not check if gcd(k, r) is 1
- */
- if (prng_descriptor[wprng].read(buf, sets[key->idx].size, prng) !=
- (unsigned long)(sets[key->idx].size)) {
- err = CRYPT_ERROR_READPRNG;
- goto LBL_ERR;
- }
-
- /* init bignums */
- if ((err = mp_init_multi(&a, &b, &k, &m, &p, &g, &p1, &tmp, NULL)) != MP_OKAY) {
- err = mpi_to_ltc_error(err);
- goto LBL_ERR;
- }
-
- /* load k and m */
- if ((err = mp_read_unsigned_bin(&m, (unsigned char *)in, inlen)) != MP_OKAY) { goto error; }
- if ((err = mp_read_unsigned_bin(&k, buf, sets[key->idx].size)) != MP_OKAY) { goto error; }
-
- /* load g, p and p1 */
- if ((err = mp_read_radix(&g, sets[key->idx].base, 64)) != MP_OKAY) { goto error; }
- if ((err = mp_read_radix(&p, sets[key->idx].prime, 64)) != MP_OKAY) { goto error; }
- if ((err = mp_sub_d(&p, 1, &p1)) != MP_OKAY) { goto error; }
- if ((err = mp_div_2(&p1, &p1)) != MP_OKAY) { goto error; } /* p1 = (p-1)/2 */
-
- /* now get a = g^k mod p */
- if ((err = mp_exptmod(&g, &k, &p, &a)) != MP_OKAY) { goto error; }
-
- /* now find M = xa + kb mod p1 or just b = (M - xa)/k mod p1 */
- if ((err = mp_invmod(&k, &p1, &k)) != MP_OKAY) { goto error; } /* k = 1/k mod p1 */
- if ((err = mp_mulmod(&a, &key->x, &p1, &tmp)) != MP_OKAY) { goto error; } /* tmp = xa */
- if ((err = mp_submod(&m, &tmp, &p1, &tmp)) != MP_OKAY) { goto error; } /* tmp = M - xa */
- if ((err = mp_mulmod(&k, &tmp, &p1, &b)) != MP_OKAY) { goto error; } /* b = (M - xa)/k */
-
- /* check for overflow */
- if ((unsigned long)(PACKET_SIZE + 4 + 4 + mp_unsigned_bin_size(&a) + mp_unsigned_bin_size(&b)) > *outlen) {
- err = CRYPT_BUFFER_OVERFLOW;
- goto LBL_ERR;
- }
-
- /* store header */
- y = PACKET_SIZE;
-
- /* now store them both (a,b) */
- x = (unsigned long)mp_unsigned_bin_size(&a);
- STORE32L(x, out+y); y += 4;
- if ((err = mp_to_unsigned_bin(&a, out+y)) != MP_OKAY) { goto error; }
- y += x;
-
- x = (unsigned long)mp_unsigned_bin_size(&b);
- STORE32L(x, out+y); y += 4;
- if ((err = mp_to_unsigned_bin(&b, out+y)) != MP_OKAY) { goto error; }
- y += x;
-
- /* check if size too big */
- if (*outlen < y) {
- err = CRYPT_BUFFER_OVERFLOW;
- goto LBL_ERR;
- }
-
- /* store header */
- packet_store_header(out, PACKET_SECT_DH, PACKET_SUB_SIGNED);
- *outlen = y;
-
- err = CRYPT_OK;
- goto LBL_ERR;
-error:
- err = mpi_to_ltc_error(err);
-LBL_ERR:
- mp_clear_multi(&tmp, &p1, &g, &p, &m, &k, &b, &a, NULL);
-
- XFREE(buf);
-
- return err;
-}
-
-
-/**
- Verify the signature given
- @param sig The signature
- @param siglen The length of the signature (octets)
- @param hash The hash that was signed
- @param hashlen The length of the hash (octets)
- @param stat [out] Result of signature comparison, 1==valid, 0==invalid
- @param key The public DH key that signed the hash
- @return CRYPT_OK if succsessful (even if signature is invalid)
-*/
-int dh_verify_hash(const unsigned char *sig, unsigned long siglen,
- const unsigned char *hash, unsigned long hashlen,
- int *stat, dh_key *key)
-{
- mp_int a, b, p, g, m, tmp;
- unsigned long x, y;
- int err;
-
- LTC_ARGCHK(sig != NULL);
- LTC_ARGCHK(hash != NULL);
- LTC_ARGCHK(stat != NULL);
- LTC_ARGCHK(key != NULL);
-
- /* default to invalid */
- *stat = 0;
-
- /* check initial input length */
- if (siglen < PACKET_SIZE+4+4) {
- return CRYPT_INVALID_PACKET;
- }
-
- /* header ok? */
- if ((err = packet_valid_header((unsigned char *)sig, PACKET_SECT_DH, PACKET_SUB_SIGNED)) != CRYPT_OK) {
- return err;
- }
-
- /* get hash out of packet */
- y = PACKET_SIZE;
-
- /* init all bignums */
- if ((err = mp_init_multi(&a, &p, &b, &g, &m, &tmp, NULL)) != MP_OKAY) {
- return mpi_to_ltc_error(err);
- }
-
- /* load a and b */
- INPUT_BIGNUM(&a, sig, x, y, siglen);
- INPUT_BIGNUM(&b, sig, x, y, siglen);
-
- /* load p and g */
- if ((err = mp_read_radix(&p, sets[key->idx].prime, 64)) != MP_OKAY) { goto error1; }
- if ((err = mp_read_radix(&g, sets[key->idx].base, 64)) != MP_OKAY) { goto error1; }
-
- /* load m */
- if ((err = mp_read_unsigned_bin(&m, (unsigned char *)hash, hashlen)) != MP_OKAY) { goto error1; }
-
- /* find g^m mod p */
- if ((err = mp_exptmod(&g, &m, &p, &m)) != MP_OKAY) { goto error1; } /* m = g^m mod p */
-
- /* find y^a * a^b */
- if ((err = mp_exptmod(&key->y, &a, &p, &tmp)) != MP_OKAY) { goto error1; } /* tmp = y^a mod p */
- if ((err = mp_exptmod(&a, &b, &p, &a)) != MP_OKAY) { goto error1; } /* a = a^b mod p */
- if ((err = mp_mulmod(&a, &tmp, &p, &a)) != MP_OKAY) { goto error1; } /* a = y^a * a^b mod p */
-
- /* y^a * a^b == g^m ??? */
- if (mp_cmp(&a, &m) == 0) {
- *stat = 1;
- }
-
- /* clean up */
- err = CRYPT_OK;
- goto done;
-error1:
- err = mpi_to_ltc_error(err);
-error:
-done:
- mp_clear_multi(&tmp, &m, &g, &p, &b, &a, NULL);
- return err;
-}
-
-
-/* $Source: /cvs/libtom/libtomcrypt/src/pk/dh/dh_sys.c,v $ */
-/* $Revision: 1.3 $ */
-/* $Date: 2005/05/05 14:35:59 $ */
View Lorry Controller Status