a528d4f0a9
If something was "present in all versions" of SSLeay, or if it was added to a version of SSLeay (and therefore predates OpenSSL), remove mention of it. Documentation history now starts with OpenSSL. Remove mention of all history before OpenSSL 0.9.8, inclusive. Remove all AUTHOR sections. Reviewed-by: Tim Hudson <tjh@openssl.org>
52 lines
1.7 KiB
Text
52 lines
1.7 KiB
Text
=pod
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=head1 NAME
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BN_rand, BN_pseudo_rand, BN_rand_range, BN_pseudo_rand_range - generate pseudo-random number
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=head1 SYNOPSIS
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#include <openssl/bn.h>
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int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
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int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);
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int BN_rand_range(BIGNUM *rnd, BIGNUM *range);
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int BN_pseudo_rand_range(BIGNUM *rnd, BIGNUM *range);
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=head1 DESCRIPTION
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BN_rand() generates a cryptographically strong pseudo-random number of
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B<bits> in length and stores it in B<rnd>. If B<top> is -1, the
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most significant bit of the random number can be zero. If B<top> is 0,
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it is set to 1, and if B<top> is 1, the two most significant bits of
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the number will be set to 1, so that the product of two such random
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numbers will always have 2*B<bits> length. If B<bottom> is true, the
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number will be odd. The value of B<bits> must be zero or greater. If B<bits> is
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1 then B<top> cannot also be 1.
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BN_pseudo_rand() does the same, but pseudo-random numbers generated by
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this function are not necessarily unpredictable. They can be used for
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non-cryptographic purposes and for certain purposes in cryptographic
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protocols, but usually not for key generation etc.
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BN_rand_range() generates a cryptographically strong pseudo-random
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number B<rnd> in the range 0 E<lt>= B<rnd> E<lt> B<range>.
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BN_pseudo_rand_range() does the same, but is based on BN_pseudo_rand(),
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and hence numbers generated by it are not necessarily unpredictable.
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The PRNG must be seeded prior to calling BN_rand() or BN_rand_range().
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=head1 RETURN VALUES
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The functions return 1 on success, 0 on error.
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The error codes can be obtained by L<ERR_get_error(3)>.
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=head1 SEE ALSO
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L<bn(3)>, L<ERR_get_error(3)>, L<rand(3)>,
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L<RAND_add(3)>, L<RAND_bytes(3)>
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=cut
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