2000-01-23 22:06:24 +00:00
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=pod
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=head1 NAME
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BN_mod_inverse - Compute inverse modulo n
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=head1 SYNOPSIS
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#include <openssl/bn.h>
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BIGNUM *BN_mod_inverse(BIGNUM *r, BIGNUM *a, const BIGNUM *n, BN_CTX *ctx);
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=head1 DESCRIPTION
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BN_mod_inverse() computes the inverse of B<a> modulo B<n>
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places the result in B<r> (C<(a*r)%n==1>). If B<r> is NULL,
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a new B<BIGNUM> is created.
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B<ctx> is a previously allocated B<BN_CTX> used for temporary
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variables. B<r> may be the same B<BIGNUM> as B<a> or B<n>.
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=head1 RETURN VALUES
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BN_mod_inverse() returns the B<BIGNUM> containing the inverse, and
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2000-01-27 01:25:31 +00:00
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NULL on error. The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
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2000-01-23 22:06:24 +00:00
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=head1 SEE ALSO
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2000-01-27 01:25:31 +00:00
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L<bn(3)|bn(3)>, L<err(3)|err(3)>, L<BN_add(3)|BN_add(3)>
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2000-01-23 22:06:24 +00:00
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=head1 HISTORY
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BN_mod_inverse() is available in all versions of SSLeay and OpenSSL.
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=cut
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