BN_mod_inverse

NAME

BN_mod_inverse — compute inverse modulo n

#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 or 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).

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