BN_mod_inverse.3ossl - Man Page

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.

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)


2023-03-21 3.0.8 OpenSSL