diff options
Diffstat (limited to 'openssl-1.1.0h/doc/crypto/BN_rand.pod')
-rw-r--r-- | openssl-1.1.0h/doc/crypto/BN_rand.pod | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/openssl-1.1.0h/doc/crypto/BN_rand.pod b/openssl-1.1.0h/doc/crypto/BN_rand.pod new file mode 100644 index 0000000..08d14de --- /dev/null +++ b/openssl-1.1.0h/doc/crypto/BN_rand.pod @@ -0,0 +1,67 @@ +=pod + +=head1 NAME + +BN_rand, BN_pseudo_rand, BN_rand_range, BN_pseudo_rand_range - generate pseudo-random number + +=head1 SYNOPSIS + + #include <openssl/bn.h> + + int BN_rand(BIGNUM *rnd, int bits, int top, int bottom); + + int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom); + + int BN_rand_range(BIGNUM *rnd, BIGNUM *range); + + int BN_pseudo_rand_range(BIGNUM *rnd, BIGNUM *range); + +=head1 DESCRIPTION + +BN_rand() generates a cryptographically strong pseudo-random number of +B<bits> in length and stores it in B<rnd>. +If B<bits> is less than zero, or too small to +accommodate the requirements specified by the B<top> and B<bottom> +parameters, an error is returned. +The B<top> parameters specifies +requirements on the most significant bit of the generated number. +If it is B<BN_RAND_TOP_ANY>, there is no constraint. +If it is B<BN_RAND_TOP_ONE>, the top bit must be one. +If it is B<BN_RAND_TOP_TWO>, the two most significant bits of +the number will be set to 1, so that the product of two such random +numbers will always have 2*B<bits> length. +If B<bottom> is B<BN_RAND_BOTTOM_ODD>, the number will be odd; if it +is B<BN_RAND_BOTTOM_ANY> it can be odd or even. +If B<bits> is 1 then B<top> cannot also be B<BN_RAND_FLG_TOPTWO>. + +BN_pseudo_rand() does the same, but pseudo-random numbers generated by +this function are not necessarily unpredictable. They can be used for +non-cryptographic purposes and for certain purposes in cryptographic +protocols, but usually not for key generation etc. + +BN_rand_range() generates a cryptographically strong pseudo-random +number B<rnd> in the range 0 E<lt>= B<rnd> E<lt> B<range>. +BN_pseudo_rand_range() does the same, but is based on BN_pseudo_rand(), +and hence numbers generated by it are not necessarily unpredictable. + +The PRNG must be seeded prior to calling BN_rand() or BN_rand_range(). + +=head1 RETURN VALUES + +The functions return 1 on success, 0 on error. +The error codes can be obtained by L<ERR_get_error(3)>. + +=head1 SEE ALSO + +L<ERR_get_error(3)>, L<RAND_add(3)>, L<RAND_bytes(3)> + +=head1 COPYRIGHT + +Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (the "License"). You may not use +this file except in compliance with the License. You can obtain a copy +in the file LICENSE in the source distribution or at +L<https://www.openssl.org/source/license.html>. + +=cut |