MirOS Manual: BN_pseudo_rand(3), BN_rand(3), BN_rand_range(3)


BN_RAND(3)                   OpenSSL                   BN_RAND(3)

NAME

     BN_rand, BN_pseudo_rand - generate pseudo-random number

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);

DESCRIPTION

     BN_rand() generates a cryptographically strong pseudo-random
     number of bits bits in length and stores it in rnd. If top
     is -1, the most significant bit of the random number can be
     zero. If top is 0, it is set to 1, and if top is 1, 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*bits length.  If bottom is true, the number will be odd.

     BN_pseudo_rand() does the same, but pseudo-random numbers
     generated by this function are not necessarily unpredict-
     able. 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 rnd in the range 0 <lt>= rnd < 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().

RETURN VALUES

     The functions return 1 on success, 0 on error. The error
     codes can be obtained by ERR_get_error(3).

SEE ALSO

     bn(3), ERR_get_error(3), rand(3), RAND_add(3), RAND_bytes(3)

HISTORY

     BN_rand() is available in all versions of SSLeay and
     OpenSSL. BN_pseudo_rand() was added in OpenSSL 0.9.5. The
     top == -1 case and the function BN_rand_range() were added
     in OpenSSL 0.9.6a. BN_pseudo_rand_range() was added in
     OpenSSL 0.9.6c.

MirOS BSD #10-current      2005-02-05                           1

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