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Diffstat (limited to 'crypto/bn/bn_prime.c')
| -rw-r--r-- | crypto/bn/bn_prime.c | 389 |
1 files changed, 389 insertions, 0 deletions
diff --git a/crypto/bn/bn_prime.c b/crypto/bn/bn_prime.c new file mode 100644 index 0000000000..07a8289492 --- /dev/null +++ b/crypto/bn/bn_prime.c @@ -0,0 +1,389 @@ +/* crypto/bn/bn_prime.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.] + */ + +#include <stdio.h> +#include <time.h> +#include "cryptlib.h" +#include "bn_lcl.h" +#include "rand.h" + +/* The quick seive algorithm approach to weeding out primes is + * Philip Zimmermann's, as implemented in PGP. I have had a read of + * his comments and implemented my own version. + */ +#include "bn_prime.h" + +#ifndef NOPROTO +static int witness(BIGNUM *a, BIGNUM *n, BN_CTX *ctx); +static int probable_prime(BIGNUM *rnd, int bits); +static int probable_prime_dh(BIGNUM *rnd, int bits, + BIGNUM *add, BIGNUM *rem, BN_CTX *ctx); +static int probable_prime_dh_strong(BIGNUM *rnd, int bits, + BIGNUM *add, BIGNUM *rem, BN_CTX *ctx); +#else +static int witness(); +static int probable_prime(); +static int probable_prime_dh(); +static int probable_prime_dh_strong(); +#endif + +BIGNUM *BN_generate_prime(bits,strong,add,rem,callback) +int bits; +int strong; +BIGNUM *add; +BIGNUM *rem; +void (*callback)(P_I_I); + { + BIGNUM *rnd=NULL; + BIGNUM *ret=NULL; + BIGNUM *t=NULL; + int i,j,c1=0; + BN_CTX *ctx; + + ctx=BN_CTX_new(); + if (ctx == NULL) goto err; + if ((rnd=BN_new()) == NULL) goto err; + if (strong) + if ((t=BN_new()) == NULL) goto err; +loop: + /* make a random number and set the top and bottom bits */ + if (add == NULL) + { + if (!probable_prime(rnd,bits)) goto err; + } + else + { + if (strong) + { + if (!probable_prime_dh_strong(rnd,bits,add,rem,ctx)) + goto err; + } + else + { + if (!probable_prime_dh(rnd,bits,add,rem,ctx)) + goto err; + } + } + /* if (BN_mod_word(rnd,(BN_ULONG)3) == 1) goto loop; */ + if (callback != NULL) callback(0,c1++); + + if (!strong) + { + i=BN_is_prime(rnd,BN_prime_checks,callback,ctx); + if (i == -1) goto err; + if (i == 0) goto loop; + } + else + { + /* for a strong prime generation, + * check that (p-1)/2 is prime. + * Since a prime is odd, We just + * need to divide by 2 */ + if (!BN_rshift1(t,rnd)) goto err; + + for (i=0; i<BN_prime_checks; i++) + { + j=BN_is_prime(rnd,1,callback,ctx); + if (j == -1) goto err; + if (j == 0) goto loop; + + j=BN_is_prime(t,1,callback,ctx); + if (j == -1) goto err; + if (j == 0) goto loop; + + if (callback != NULL) callback(2,c1-1); + /* We have a strong prime test pass */ + } + } + /* we have a prime :-) */ + ret=rnd; +err: + if ((ret == NULL) && (rnd != NULL)) BN_free(rnd); + if (t != NULL) BN_free(t); + if (ctx != NULL) BN_CTX_free(ctx); + return(ret); + } + +int BN_is_prime(a,checks,callback,ctx_passed) +BIGNUM *a; +int checks; +void (*callback)(P_I_I); +BN_CTX *ctx_passed; + { + int i,j,c2=0,ret= -1; + BIGNUM *check; + BN_CTX *ctx; + + if (ctx_passed != NULL) + ctx=ctx_passed; + else + if ((ctx=BN_CTX_new()) == NULL) goto err; + + check=ctx->bn[ctx->tos++]; + for (i=0; i<checks; i++) + { + if (!BN_rand(check,BN_num_bits(a)-1,0,0)) goto err; + j=witness(check,a,ctx); + if (j == -1) goto err; + if (j) + { + ret=0; + goto err; + } + if (callback != NULL) callback(1,c2++); + } + ret=1; +err: + ctx->tos--; + if ((ctx_passed == NULL) && (ctx != NULL)) + BN_CTX_free(ctx); + + return(ret); + } + +#define RECP_MUL_MOD + +static int witness(a, n,ctx) +BIGNUM *a; +BIGNUM *n; +BN_CTX *ctx; + { + int k,i,nb,ret= -1; + BIGNUM *d,*dd,*tmp; + BIGNUM *d1,*d2,*x,*n1,*inv; + + d1=ctx->bn[ctx->tos]; + d2=ctx->bn[ctx->tos+1]; + x=ctx->bn[ctx->tos+2]; + n1=ctx->bn[ctx->tos+3]; + inv=ctx->bn[ctx->tos+4]; + ctx->tos+=5; + + d=d1; + dd=d2; + if (!BN_one(d)) goto err; + if (!BN_sub(n1,n,d)) goto err; /* n1=n-1; */ + k=BN_num_bits(n1); + + /* i=BN_num_bits(n); */ +#ifdef RECP_MUL_MOD + nb=BN_reciprocal(inv,n,ctx); /**/ + if (nb == -1) goto err; +#endif + + for (i=k-1; i>=0; i--) + { + if (BN_copy(x,d) == NULL) goto err; +#ifndef RECP_MUL_MOD + if (!BN_mod_mul(dd,d,d,n,ctx)) goto err; +#else + if (!BN_mod_mul_reciprocal(dd,d,d,n,inv,nb,ctx)) goto err; +#endif + if ( BN_is_one(dd) && + !BN_is_one(x) && + (BN_cmp(x,n1) != 0)) + { + ret=1; + goto err; + } + if (BN_is_bit_set(n1,i)) + { +#ifndef RECP_MUL_MOD + if (!BN_mod_mul(d,dd,a,n,ctx)) goto err; +#else + if (!BN_mod_mul_reciprocal(d,dd,a,n,inv,nb,ctx)) goto err; +#endif + } + else + { + tmp=d; + d=dd; + dd=tmp; + } + } + if (BN_is_one(d)) + i=0; + else i=1; + ret=i; +err: + ctx->tos-=5; + return(ret); + } + +static int probable_prime(rnd, bits) +BIGNUM *rnd; +int bits; + { + int i; + MS_STATIC BN_ULONG mods[NUMPRIMES]; + BN_ULONG delta; + + if (!BN_rand(rnd,bits,1,1)) return(0); + /* we now have a random number 'rand' to test. */ + for (i=1; i<NUMPRIMES; i++) + mods[i]=BN_mod_word(rnd,(BN_ULONG)primes[i]); + delta=0; + loop: for (i=1; i<NUMPRIMES; i++) + { + /* check that rnd is not a prime and also + * that gcd(rnd-1,primes) == 1 (except for 2) */ + if (((mods[i]+delta)%primes[i]) <= 1) + { + delta+=2; + /* perhaps need to check for overflow of + * delta (but delta can be upto 2^32) */ + goto loop; + } + } + if (!BN_add_word(rnd,delta)) return(0); + return(1); + } + +static int probable_prime_dh(rnd, bits, add, rem,ctx) +BIGNUM *rnd; +int bits; +BIGNUM *add; +BIGNUM *rem; +BN_CTX *ctx; + { + int i,ret=0; + BIGNUM *t1; + + t1=ctx->bn[ctx->tos++]; + + if (!BN_rand(rnd,bits,0,1)) goto err; + + /* we need ((rnd-rem) % add) == 0 */ + + if (!BN_mod(t1,rnd,add,ctx)) goto err; + if (!BN_sub(rnd,rnd,t1)) goto err; + if (rem == NULL) + { if (!BN_add_word(rnd,1)) goto err; } + else + { if (!BN_add(rnd,rnd,rem)) goto err; } + + /* we now have a random number 'rand' to test. */ + + loop: for (i=1; i<NUMPRIMES; i++) + { + /* check that rnd is a prime */ + if (BN_mod_word(rnd,(BN_LONG)primes[i]) <= 1) + { + if (!BN_add(rnd,rnd,add)) goto err; + goto loop; + } + } + ret=1; +err: + ctx->tos--; + return(ret); + } + +static int probable_prime_dh_strong(p, bits, padd, rem,ctx) +BIGNUM *p; +int bits; +BIGNUM *padd; +BIGNUM *rem; +BN_CTX *ctx; + { + int i,ret=0; + BIGNUM *t1,*qadd=NULL,*q=NULL; + + bits--; + t1=ctx->bn[ctx->tos++]; + q=ctx->bn[ctx->tos++]; + qadd=ctx->bn[ctx->tos++]; + + if (!BN_rshift1(qadd,padd)) goto err; + + if (!BN_rand(q,bits,0,1)) goto err; + + /* we need ((rnd-rem) % add) == 0 */ + if (!BN_mod(t1,q,qadd,ctx)) goto err; + if (!BN_sub(q,q,t1)) goto err; + if (rem == NULL) + { if (!BN_add_word(q,1)) goto err; } + else + { + if (!BN_rshift1(t1,rem)) goto err; + if (!BN_add(q,q,t1)) goto err; + } + + /* we now have a random number 'rand' to test. */ + if (!BN_lshift1(p,q)) goto err; + if (!BN_add_word(p,1)) goto err; + + loop: for (i=1; i<NUMPRIMES; i++) + { + /* check that p and q are prime */ + /* check that for p and q + * gcd(p-1,primes) == 1 (except for 2) */ + if ( (BN_mod_word(p,(BN_LONG)primes[i]) == 0) || + (BN_mod_word(q,(BN_LONG)primes[i]) == 0)) + { + if (!BN_add(p,p,padd)) goto err; + if (!BN_add(q,q,qadd)) goto err; + goto loop; + } + } + ret=1; +err: + ctx->tos-=3; + return(ret); + } + |