/* crypto/dh/dh_key.c */ /* Copyright (C) 1995-1998 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.] */ #include #include "cryptlib.h" #include #include #include static int generate_key(DH *dh); static int compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh); static int dh_bn_mod_exp(DH *dh, BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx); static int dh_init(DH *dh); static int dh_finish(DH *dh); int DH_generate_key(DH *dh) { return dh->meth->generate_key(dh); } int DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh) { return dh->meth->compute_key(key, pub_key, dh); } static DH_METHOD dh_ossl = { "OpenSSL DH Method", generate_key, compute_key, dh_bn_mod_exp, dh_init, dh_finish, 0, NULL }; DH_METHOD *DH_OpenSSL(void) { return &dh_ossl; } static int generate_key(DH *dh) { int ok=0; unsigned int i; BN_CTX ctx; BN_MONT_CTX *mont; BIGNUM *pub_key=NULL,*priv_key=NULL; BN_CTX_init(&ctx); if (dh->priv_key == NULL) { i=dh->length; if (i == 0) { /* Make the number p-1 bits long */ i=BN_num_bits(dh->p)-1; } priv_key=BN_new(); if (priv_key == NULL) goto err; if (!BN_rand(priv_key,i,0,0)) goto err; } else priv_key=dh->priv_key; if (dh->pub_key == NULL) { pub_key=BN_new(); if (pub_key == NULL) goto err; } else pub_key=dh->pub_key; if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P)) { if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p, dh->p,&ctx)) goto err; } mont=(BN_MONT_CTX *)dh->method_mont_p; if (!dh->meth->bn_mod_exp(dh, pub_key,dh->g,priv_key,dh->p,&ctx,mont)) goto err; dh->pub_key=pub_key; dh->priv_key=priv_key; ok=1; err: if (ok != 1) DHerr(DH_F_DH_GENERATE_KEY,ERR_R_BN_LIB); if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key); if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key); BN_CTX_free(&ctx); return(ok); } static int compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh) { BN_CTX ctx; BN_MONT_CTX *mont; BIGNUM *tmp; int ret= -1; BN_CTX_init(&ctx); tmp= &(ctx.bn[ctx.tos++]); if (dh->priv_key == NULL) { DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE); goto err; } if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P)) { if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p, dh->p,&ctx)) goto err; } mont=(BN_MONT_CTX *)dh->method_mont_p; if (!dh->meth->bn_mod_exp(dh, tmp,pub_key,dh->priv_key,dh->p,&ctx,mont)) { DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB); goto err; } ret=BN_bn2bin(tmp,key); err: BN_CTX_free(&ctx); return(ret); } static int dh_bn_mod_exp(DH *dh, BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx) { return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx); } static int dh_init(DH *dh) { dh->flags |= DH_FLAG_CACHE_MONT_P; return(1); } static int dh_finish(DH *dh) { if(dh->method_mont_p) BN_MONT_CTX_free((BN_MONT_CTX *)dh->method_mont_p); return(1); }