/* crypto/dsa/dsa_gen.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.] */ #undef GENUINE_DSA #ifdef GENUINE_DSA #define HASH SHA #else #define HASH SHA1 #endif #include #include #include "cryptlib.h" #include "sha.h" #include "bn.h" #include "dsa.h" #include "rand.h" DSA *DSA_generate_parameters(bits,seed_in,seed_len,counter_ret,h_ret,callback, cb_arg) int bits; unsigned char *seed_in; int seed_len; int *counter_ret; unsigned long *h_ret; void (*callback)(); char *cb_arg; { int ok=0; unsigned char seed[SHA_DIGEST_LENGTH]; unsigned char md[SHA_DIGEST_LENGTH]; unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH]; BIGNUM *r0,*W,*X,*c,*test; BIGNUM *g=NULL,*q=NULL,*p=NULL; BN_MONT_CTX *mont=NULL; int k,n=0,i,b,m=0; int counter=0; BN_CTX *ctx=NULL,*ctx2=NULL; unsigned int h=2; DSA *ret=NULL; if (bits < 512) bits=512; bits=(bits+63)/64*64; if ((seed_in != NULL) && (seed_len == 20)) memcpy(seed,seed_in,seed_len); if ((ctx=BN_CTX_new()) == NULL) goto err; if ((ctx2=BN_CTX_new()) == NULL) goto err; if ((ret=DSA_new()) == NULL) goto err; if ((mont=BN_MONT_CTX_new()) == NULL) goto err; r0= &(ctx2->bn[0]); g= &(ctx2->bn[1]); W= &(ctx2->bn[2]); q= &(ctx2->bn[3]); X= &(ctx2->bn[4]); c= &(ctx2->bn[5]); p= &(ctx2->bn[6]); test= &(ctx2->bn[7]); BN_lshift(test,BN_value_one(),bits-1); for (;;) { for (;;) { /* step 1 */ if (callback != NULL) callback(0,m++,cb_arg); if (!seed_len) RAND_bytes(seed,SHA_DIGEST_LENGTH); else seed_len=0; memcpy(buf,seed,SHA_DIGEST_LENGTH); memcpy(buf2,seed,SHA_DIGEST_LENGTH); for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) { buf[i]++; if (buf[i] != 0) break; } /* step 2 */ HASH(seed,SHA_DIGEST_LENGTH,md); HASH(buf,SHA_DIGEST_LENGTH,buf2); for (i=0; i 0) break; /* do a callback call */ /* step 5 */ } if (callback != NULL) callback(2,0,cb_arg); if (callback != NULL) callback(3,0,cb_arg); /* step 6 */ counter=0; n=(bits-1)/160; b=(bits-1)-n*160; for (;;) { /* step 7 */ BN_zero(W); for (k=0; k<=n; k++) { for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) { buf[i]++; if (buf[i] != 0) break; } HASH(buf,SHA_DIGEST_LENGTH,md); /* step 8 */ if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) abort(); BN_lshift(r0,r0,160*k); BN_add(W,W,r0); } /* more of step 8 */ BN_mask_bits(W,bits-1); BN_copy(X,W); /* this should be ok */ BN_add(X,X,test); /* this should be ok */ /* step 9 */ BN_lshift1(r0,q); BN_mod(c,X,r0,ctx); BN_sub(r0,c,BN_value_one()); BN_sub(p,X,r0); /* step 10 */ if (BN_cmp(p,test) >= 0) { /* step 11 */ if (DSA_is_prime(p,callback,cb_arg) > 0) goto end; } /* step 13 */ counter++; /* step 14 */ if (counter >= 4096) break; if (callback != NULL) callback(0,counter,cb_arg); } } end: if (callback != NULL) callback(2,1,cb_arg); /* We now need to gernerate g */ /* Set r0=(p-1)/q */ BN_sub(test,p,BN_value_one()); BN_div(r0,NULL,test,q,ctx); BN_set_word(test,h); BN_MONT_CTX_set(mont,p,ctx); for (;;) { /* g=test^r0%p */ BN_mod_exp_mont(g,test,r0,p,ctx,mont); if (!BN_is_one(g)) break; BN_add(test,test,BN_value_one()); h++; } if (callback != NULL) callback(3,1,cb_arg); ok=1; err: if (!ok) { if (ret != NULL) DSA_free(ret); } else { ret->p=BN_dup(p); ret->q=BN_dup(q); ret->g=BN_dup(g); if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20); if (counter_ret != NULL) *counter_ret=counter; if (h_ret != NULL) *h_ret=h; } if (ctx != NULL) BN_CTX_free(ctx); if (ctx != NULL) BN_CTX_free(ctx2); if (mont != NULL) BN_MONT_CTX_free(mont); return(ok?ret:NULL); } int DSA_is_prime(w, callback,cb_arg) BIGNUM *w; void (*callback)(); char *cb_arg; { int ok= -1,j,i,n; BN_CTX *ctx=NULL,*ctx2=NULL; BIGNUM *w_1,*b,*m,*z,*tmp,*mont_1; int a; BN_MONT_CTX *mont=NULL; if (!BN_is_bit_set(w,0)) return(0); if ((ctx=BN_CTX_new()) == NULL) goto err; if ((ctx2=BN_CTX_new()) == NULL) goto err; if ((mont=BN_MONT_CTX_new()) == NULL) goto err; m= &(ctx2->bn[2]); b= &(ctx2->bn[3]); z= &(ctx2->bn[4]); w_1= &(ctx2->bn[5]); tmp= &(ctx2->bn[6]); mont_1= &(ctx2->bn[7]); /* step 1 */ n=50; /* step 2 */ if (!BN_sub(w_1,w,BN_value_one())) goto err; for (a=1; !BN_is_bit_set(w_1,a); a++) ; if (!BN_rshift(m,w_1,a)) goto err; BN_MONT_CTX_set(mont,w,ctx); BN_to_montgomery(mont_1,BN_value_one(),mont,ctx); BN_to_montgomery(w_1,w_1,mont,ctx); for (i=1; i < n; i++) { /* step 3 */ BN_rand(b,BN_num_bits(w)-2/*-1*/,0,0); /* BN_set_word(b,0x10001L); */ /* step 4 */ j=0; if (!BN_mod_exp_mont(z,b,m,w,ctx,mont)) goto err; if (!BN_to_montgomery(z,z,mont,ctx)) goto err; /* step 5 */ for (;;) { if (((j == 0) && (BN_cmp(z,mont_1) == 0)) || (BN_cmp(z,w_1) == 0)) break; /* step 6 */ if ((j > 0) && (BN_cmp(z,mont_1) == 0)) { ok=0; goto err; } j++; if (j >= a) { ok=0; goto err; } if (!BN_mod_mul_montgomery(z,z,z,mont,ctx)) goto err; if (callback != NULL) callback(1,j,cb_arg); } } ok=1; err: if (ok == -1) DSAerr(DSA_F_DSA_IS_PRIME,ERR_R_BN_LIB); BN_CTX_free(ctx); BN_CTX_free(ctx2); return(ok); }