1=pod 2 3=head1 NAME 4 5BN_mod_inverse - compute inverse modulo n 6 7=head1 SYNOPSIS 8 9 #include <openssl/bn.h> 10 11 BIGNUM *BN_mod_inverse(BIGNUM *r, BIGNUM *a, const BIGNUM *n, 12 BN_CTX *ctx); 13 14=head1 DESCRIPTION 15 16BN_mod_inverse() computes the inverse of B<a> modulo B<n> 17places the result in B<r> (C<(a*r)%n==1>). If B<r> is NULL, 18a new B<BIGNUM> is created. 19 20B<ctx> is a previously allocated B<BN_CTX> used for temporary 21variables. B<r> may be the same B<BIGNUM> as B<a> or B<n>. 22 23=head1 RETURN VALUES 24 25BN_mod_inverse() returns the B<BIGNUM> containing the inverse, and 26NULL on error. The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>. 27 28=head1 SEE ALSO 29 30L<bn(3)|bn(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<BN_add(3)|BN_add(3)> 31 32=head1 HISTORY 33 34BN_mod_inverse() is available in all versions of SSLeay and OpenSSL. 35 36=cut 37