BN_RAND(3)                 Library Functions Manual                 BN_RAND(3)

NAME
     BN_rand, BN_rand_range, BN_pseudo_rand, BN_pseudo_rand_range - generate
     pseudo-random number

SYNOPSIS
     #include <openssl/bn.h>

     int
     BN_rand(BIGNUM *rnd, int bits, int top, int bottom);

     int
     BN_rand_range(BIGNUM *rnd, const BIGNUM *range);

DESCRIPTION
     BN_rand() generates a cryptographically strong pseudo-random number of
     bits in length and stores it in rnd.  If top is BN_RAND_TOP_ANY, the most
     significant bit of the random number can be zero.  If top is
     BN_RAND_TOP_ONE, the most significant bit is set to 1, and if top is
     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*bits length.  If bottom is BN_RAND_BOTTOM_ODD, the number will be odd;
     if it is BN_RAND_BOTTOM_ANY, it can be odd or even.  The value of bits
     must be zero or greater.  If bits is +1 then top cannot be
     BN_RAND_TOP_TWO.

     BN_rand_range() generates a cryptographically strong pseudo-random number
     rnd in the range 0 <= rnd < range.

     BN_pseudo_rand() is a deprecated alias for BN_rand(), and
     BN_pseudo_rand_range() for 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_new(3)

HISTORY
     BN_rand() first appeared in SSLeay 0.5.1 and has been available since
     OpenBSD 2.4.

     The top == -1 case and the function BN_rand_range() first appeared in
     OpenSSL 0.9.6a and have been available since OpenBSD 3.0.

Linux 6.8.2-arch2-1            November 30, 2021           Linux 6.8.2-arch2-1