NAME

       BN_mod_inverse - compute inverse modulo n

SYNOPSIS

        #include <openssl/bn.h>

        BIGNUM *BN_mod_inverse(BIGNUM *r, BIGNUM *a, const BIGNUM *n,
                               BN_CTX *ctx);

DESCRIPTION

       BN_mod_inverse() computes the inverse of a modulo n places the result in r ("(a*r)%n==1").
       If r is NULL, a new BIGNUM is created.

       ctx is a previously allocated BN_CTX used for temporary variables. r may be the same
       BIGNUM as a or n.

RETURN VALUES

       BN_mod_inverse() returns the BIGNUM containing the inverse, and NULL on error. The error
       codes can be obtained by ERR_get_error(3).

SEE ALSO

       ERR_get_error(3), BN_add(3)

COPYRIGHT

       Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except
       in compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.