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)>.
27
28=head1 SEE ALSO
29
30L<ERR_get_error(3)>, L<BN_add(3)>
31
32=head1 COPYRIGHT
33
34Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
35
36Licensed under the OpenSSL license (the "License").  You may not use
37this file except in compliance with the License.  You can obtain a copy
38in the file LICENSE in the source distribution or at
39L<https://www.openssl.org/source/license.html>.
40
41=cut
42