X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=doc%2Fcrypto%2FBN_generate_prime.pod;h=7dccacbc1e553f6cf47cbfe4ce1eb9b8eea7404c;hb=ec14c80c7cd4949af0b2d85e4bd2952d22c1707f;hp=3cd239e89395158ef8d5255f55f3e3d9f5b80883;hpb=bb075f883356589425b7e57f788c7498a83b0219;p=oweals%2Fopenssl.git diff --git a/doc/crypto/BN_generate_prime.pod b/doc/crypto/BN_generate_prime.pod index 3cd239e893..7dccacbc1e 100644 --- a/doc/crypto/BN_generate_prime.pod +++ b/doc/crypto/BN_generate_prime.pod @@ -2,7 +2,7 @@ =head1 NAME -BN_generate_prime, BN_is_prime - Generate primes and test for primality +BN_generate_prime, BN_is_prime, BN_is_prime_fasttest - generate primes and test for primality =head1 SYNOPSIS @@ -11,14 +11,18 @@ BN_generate_prime, BN_is_prime - Generate primes and test for primality BIGNUM *BN_generate_prime(BIGNUM *ret, int num, int safe, BIGNUM *add, BIGNUM *rem, void (*callback)(int, int, void *), void *cb_arg); - int BN_is_prime(BIGNUM *a, int checks, void (*callback)(int, int, + int BN_is_prime(const BIGNUM *a, int checks, void (*callback)(int, int, void *), BN_CTX *ctx, void *cb_arg); + int BN_is_prime_fasttest(const BIGNUM *a, int checks, + void (*callback)(int, int, void *), BN_CTX *ctx, void *cb_arg, + int do_trial_division); + =head1 DESCRIPTION BN_generate_prime() generates a pseudo-random prime number of B bits. -If B is not NULL, it will be used to store the number. +If B is not B, it will be used to store the number. If B is not B, it is called as follows: @@ -43,8 +47,8 @@ When a prime has been found, B is called. The prime may have to fulfill additional requirements for use in Diffie-Hellman key exchange: -If B is not NULL, the prime will fulfill the condition p % B -== B (p % B == 1 if B == NULL) in order to suit a given +If B is not B, the prime will fulfill the condition p % B +== B (p % B == 1 if B == B) in order to suit a given generator. If B is true, it will be a safe prime (i.e. a prime p so @@ -53,20 +57,30 @@ that (p-1)/2 is also prime). The PRNG must be seeded prior to calling BN_generate_prime(). The prime number generation has a negligible error probability. -BN_is_prime() tests if the number B is prime. This is done by -performing a Miller-Rabin probabilistic primality test with B -iterations. If B, it uses a number -of iterations that yields a false positive rate of at most 2^-80 for -random input. +BN_is_prime() and BN_is_prime_fasttest() test if the number B is +prime. The following tests are performed until one of them shows that +B is composite; if B passes all these tests, it is considered +prime. + +BN_is_prime_fasttest(), when called with B, +first attempts trial division by a number of small primes; +if no divisors are found by this test and B is not B, +B is called. +If B, this test is skipped. + +Both BN_is_prime() and BN_is_prime_fasttest() perform a Miller-Rabin +probabilistic primality test with B iterations. If +B, a number of iterations is used that +yields a false positive rate of at most 2^-80 for random input. If B is not B, B is called -after the j-th iteration. B is a pre-allocated B (to save -the overhead of allocating and freeing the structure in a loop), or -NULL. +after the j-th iteration (j = 0, 1, ...). B is a +pre-allocated B (to save the overhead of allocating and +freeing the structure in a loop), or B. =head1 RETURN VALUES -BN_generate_prime() returns the prime number on success, NULL otherwise. +BN_generate_prime() returns the prime number on success, B otherwise. BN_is_prime() returns 0 if the number is composite, 1 if it is prime with an error probability of less than 0.25^B, and @@ -76,12 +90,13 @@ The error codes can be obtained by L. =head1 SEE ALSO -L, L, L +L, L, L =head1 HISTORY The B arguments to BN_generate_prime() and to BN_is_prime() were added in SSLeay 0.9.0. The B argument to BN_generate_prime() was added in SSLeay 0.9.1. +BN_is_prime_fasttest() was added in OpenSSL 0.9.5. =cut