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Diffstat (limited to 'crypto/dsa/dsa_vrf.c')
| -rw-r--r-- | crypto/dsa/dsa_vrf.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/crypto/dsa/dsa_vrf.c b/crypto/dsa/dsa_vrf.c new file mode 100644 index 000000000..a217f8631 --- /dev/null +++ b/crypto/dsa/dsa_vrf.c @@ -0,0 +1,152 @@ +/* crypto/dsa/dsa_vrf.c */ +/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com) + * All rights reserved. + * + * This package is an SSL implementation written + * by Eric Young (eay@cryptsoft.com). + * The implementation was written so as to conform with Netscapes SSL. + * + * This library is free for commercial and non-commercial use as long as + * the following conditions are aheared to. The following conditions + * apply to all code found in this distribution, be it the RC4, RSA, + * lhash, DES, etc., code; not just the SSL code. The SSL documentation + * included with this distribution is covered by the same copyright terms + * except that the holder is Tim Hudson (tjh@cryptsoft.com). + * + * Copyright remains Eric Young's, and as such any Copyright notices in + * the code are not to be removed. + * If this package is used in a product, Eric Young should be given attribution + * as the author of the parts of the library used. + * This can be in the form of a textual message at program startup or + * in documentation (online or textual) provided with the package. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * "This product includes cryptographic software written by + * Eric Young (eay@cryptsoft.com)" + * The word 'cryptographic' can be left out if the rouines from the library + * being used are not cryptographic related :-). + * 4. If you include any Windows specific code (or a derivative thereof) from + * the apps directory (application code) you must include an acknowledgement: + * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" + * + * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * The licence and distribution terms for any publically available version or + * derivative of this code cannot be changed. i.e. this code cannot simply be + * copied and put under another distribution licence + * [including the GNU Public Licence.] + */ + +/* Origional version from Steven Schoch <schoch@sheba.arc.nasa.gov> */ + +#include <stdio.h> +#include "cryptlib.h" +#include "bn.h" +#include "dsa.h" +#include "rand.h" +#include "asn1.h" +#include "asn1_mac.h" + +/* data has already been hashed (probably with SHA or SHA-1). */ +/* returns + * 1: correct signature + * 0: incorrect signature + * -1: error + */ +int DSA_verify(type,dgst,dgst_len,sigbuf,siglen, dsa) +int type; +unsigned char *dgst; +int dgst_len; +unsigned char *sigbuf; +int siglen; +DSA *dsa; + { + /* The next 3 are used by the M_ASN1 macros */ + long length=siglen; + ASN1_CTX c; + unsigned char **pp= &sigbuf; + BN_CTX *ctx; + BIGNUM *r=NULL; + BIGNUM *t1=NULL,*t2=NULL; + BIGNUM *u1=NULL,*u2=NULL; + ASN1_INTEGER *bs=NULL; + int ret = -1; + + ctx=BN_CTX_new(); + if (ctx == NULL) goto err; + + t1=BN_new(); + t2=BN_new(); + if (t1 == NULL || t2 == NULL) goto err; + + M_ASN1_D2I_Init(); + M_ASN1_D2I_start_sequence(); + M_ASN1_D2I_get(bs,d2i_ASN1_INTEGER); + if ((r=BN_bin2bn(bs->data,bs->length,NULL)) == NULL) goto err_bn; + M_ASN1_D2I_get(bs,d2i_ASN1_INTEGER); + if ((u1=BN_bin2bn(bs->data,bs->length,NULL)) == NULL) goto err_bn; + if (!asn1_Finish(&c)) goto err; + + /* Calculate W = inv(S) mod Q + * save W in u2 */ + if ((u2=BN_mod_inverse(u1,dsa->q,ctx)) == NULL) goto err_bn; + + /* save M in u1 */ + if (BN_bin2bn(dgst,dgst_len,u1) == NULL) goto err_bn; + + /* u1 = M * w mod q */ + if (!BN_mod_mul(u1,u1,u2,dsa->q,ctx)) goto err_bn; + + /* u2 = r * w mod q */ + if (!BN_mod_mul(u2,r,u2,dsa->q,ctx)) goto err_bn; + + /* v = ( g^u1 * y^u2 mod p ) mod q */ + /* let t1 = g ^ u1 mod p */ + if (!BN_mod_exp(t1,dsa->g,u1,dsa->p,ctx)) goto err_bn; + /* let t2 = y ^ u2 mod p */ + if (!BN_mod_exp(t2,dsa->pub_key,u2,dsa->p,ctx)) goto err_bn; + /* let u1 = t1 * t2 mod p */ + if (!BN_mod_mul(u1,t1,t2,dsa->p,ctx)) goto err_bn; + /* let u1 = u1 mod q */ + if (!BN_mod(u1,u1,dsa->q,ctx)) goto err_bn; + /* V is now in u1. If the signature is correct, it will be + * equal to R. */ + ret=(BN_ucmp(u1, r) == 0); + if (0) + { +err: /* ASN1 error */ + DSAerr(DSA_F_DSA_VERIFY,c.error); + } + if (0) + { +err_bn: /* BN error */ + DSAerr(DSA_F_DSA_VERIFY,ERR_R_BN_LIB); + } + if (ctx != NULL) BN_CTX_free(ctx); + if (r != NULL) BN_free(r); + if (t1 != NULL) BN_free(t1); + if (t2 != NULL) BN_free(t2); + if (u1 != NULL) BN_free(u1); + if (u2 != NULL) BN_free(u2); + if (bs != NULL) ASN1_BIT_STRING_free(bs); + return(ret); + } |