BN_mod_inverse.3ossl - Man Page

 #include <openssl/bn.h>

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

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.

It is an error to use the same BIGNUM as n.

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

ERR_get_error(3), BN_add(3)

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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>.