diff --git a/CHANGES b/CHANGES index aa62657c18e757df6515cccc9a2d52816a2171d7..8ec710732e81b219de43779718dbd6fe7a8f0158 100644 --- a/CHANGES +++ b/CHANGES @@ -4,6 +4,14 @@ Changes between 0.9.4 and 0.9.5 [xx XXX 1999] + *) Do more iterations of Rabin-Miller probable prime test (specifically, + 3 for 1024-bit primes, 6 for 512-bit primes, 12 for 256-bit primes + instead of only 2 for all lengths; see BN_prime_checks definition + in crypto/bn/bn.h for the complete table). This guarantees a + false-positive rate of at most 2^-80 (actually less because we are + additionally doing trial division) for random input. + [Bodo Moeller] + *) Rewrite ssl3_read_n (ssl/s3_pkt.c) avoiding a couple of bugs. [Bodo Moeller] diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h index f935e1ca79d7f1699d56cfbbdd5fadb09b26df84..dd1d263098dec754759bc6b42be2af3af53c2d59 100644 --- a/crypto/bn/bn.h +++ b/crypto/bn/bn.h @@ -283,7 +283,23 @@ typedef struct bn_recp_ctx_st #define BN_to_montgomery(r,a,mont,ctx) BN_mod_mul_montgomery(\ r,a,&((mont)->RR),(mont),ctx) -#define BN_prime_checks (5) +/* number of Miller-Rabin iterations for an error rate of less than 2^-80 + * for random 'b'-bit input, b >= 100 (taken from table 4.4 in the Handbook + * of Applied Cryptography [Menezes, van Oorschot, Vanstone; CRC Press 1996]; + * original paper: Damgaard, Landrock, Pomerance: Average case error estimates + * for the strong probable prime test. -- Math. Comp. 61 (1993) 177-194) */ +#define BN_prime_checks(b) ((b) >= 1300 ? 2 : \ + (b) >= 850 ? 3 : \ + (b) >= 650 ? 4 : \ + (b) >= 550 ? 5 : \ + (b) >= 450 ? 6 : \ + (b) >= 400 ? 7 : \ + (b) >= 350 ? 8 : \ + (b) >= 300 ? 9 : \ + (b) >= 250 ? 12 : \ + (b) >= 200 ? 15 : \ + (b) >= 150 ? 18 : \ + /* b >= 100 */ 27) #define BN_num_bytes(a) ((BN_num_bits(a)+7)/8) #define BN_is_word(a,w) (((a)->top == 1) && ((a)->d[0] == (BN_ULONG)(w))) @@ -381,7 +397,7 @@ int BN_hex2bn(BIGNUM **a, const char *str); int BN_dec2bn(BIGNUM **a, const char *str); int BN_gcd(BIGNUM *r,BIGNUM *in_a,BIGNUM *in_b,BN_CTX *ctx); BIGNUM *BN_mod_inverse(BIGNUM *ret,BIGNUM *a, const BIGNUM *n,BN_CTX *ctx); -BIGNUM *BN_generate_prime(BIGNUM *ret,int bits,int strong,BIGNUM *add, +BIGNUM *BN_generate_prime(BIGNUM *ret,int bits,int safe,BIGNUM *add, BIGNUM *rem,void (*callback)(int,int,void *),void *cb_arg); int BN_is_prime(BIGNUM *p,int nchecks,void (*callback)(int,int,void *), BN_CTX *ctx,void *cb_arg); diff --git a/crypto/bn/bn_prime.c b/crypto/bn/bn_prime.c index 6fa0f9be1ee32b4767e8ed154832b88923601119..57305c7273b5b271665a0d9d29e0453b2849d1d8 100644 --- a/crypto/bn/bn_prime.c +++ b/crypto/bn/bn_prime.c @@ -73,15 +73,16 @@ static int witness(BIGNUM *a, BIGNUM *n, BN_CTX *ctx,BN_CTX *ctx2, 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, +static int probable_prime_dh_safe(BIGNUM *rnd, int bits, BIGNUM *add, BIGNUM *rem, BN_CTX *ctx); -BIGNUM *BN_generate_prime(BIGNUM *ret, int bits, int strong, BIGNUM *add, +BIGNUM *BN_generate_prime(BIGNUM *ret, int bits, int safe, BIGNUM *add, BIGNUM *rem, void (*callback)(int,int,void *), void *cb_arg) { BIGNUM *rnd=NULL; BIGNUM t; int i,j,c1=0; BN_CTX *ctx; + int checks = BN_prime_checks(bits); ctx=BN_CTX_new(); if (ctx == NULL) goto err; @@ -100,9 +101,9 @@ loop: } else { - if (strong) + if (safe) { - if (!probable_prime_dh_strong(rnd,bits,add,rem,ctx)) + if (!probable_prime_dh_safe(rnd,bits,add,rem,ctx)) goto err; } else @@ -114,21 +115,21 @@ loop: /* if (BN_mod_word(rnd,(BN_ULONG)3) == 1) goto loop; */ if (callback != NULL) callback(0,c1++,cb_arg); - if (!strong) + if (!safe) { - i=BN_is_prime(rnd,BN_prime_checks,callback,ctx,cb_arg); + i=BN_is_prime(rnd,checks,callback,ctx,cb_arg); if (i == -1) goto err; if (i == 0) goto loop; } else { - /* for a strong prime generation, + /* for "safe 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; ip,BN_prime_checks,NULL,ctx,NULL)) + if (!BN_is_prime(dh->p,BN_prime_checks(BN_num_bits(dh->p)),NULL,ctx,NULL)) *ret|=DH_CHECK_P_NOT_PRIME; else { if (!BN_rshift1(q,dh->p)) goto err; - if (!BN_is_prime(q,BN_prime_checks,NULL,ctx,NULL)) + if (!BN_is_prime(q,BN_prime_checks(BN_num_bits(q)),NULL,ctx,NULL)) *ret|=DH_CHECK_P_NOT_STRONG_PRIME; } ok=1; diff --git a/crypto/rsa/rsa_chk.c b/crypto/rsa/rsa_chk.c index 91b91157983fe9e09025f7896314bec53c8dc82d..03497f846387fbeb555f129124c3d7caf14e9a5e 100644 --- a/crypto/rsa/rsa_chk.c +++ b/crypto/rsa/rsa_chk.c @@ -75,7 +75,7 @@ int RSA_check_key(RSA *key) } /* p prime? */ - r = BN_is_prime(key->p, BN_prime_checks, NULL, NULL, NULL); + r = BN_is_prime(key->p, BN_prime_checks(BN_num_bits(key->p)), NULL, NULL, NULL); if (r != 1) { ret = r; @@ -85,7 +85,7 @@ int RSA_check_key(RSA *key) } /* q prime? */ - r = BN_is_prime(key->q, BN_prime_checks, NULL, NULL, NULL); + r = BN_is_prime(key->q, BN_prime_checks(BN_num_bits(key->q)), NULL, NULL, NULL); if (r != 1) { ret = r;