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 add 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, or NULL on error. The error codes can be obtained by ERR_get_error(3).

SEE ALSO

bn(3), BN_add(3), ERR_get_error(3)

HISTORY

BN_mod_inverse() is available in all versions of SSLeay and OpenSSL.