OpenSSL

Cryptography and SSL/TLS Toolkit

NAME

BN_cmp, BN_ucmp, BN_is_zero, BN_is_one, BN_is_word, BN_abs_is_word, BN_is_odd, BN_are_coprime - BIGNUM comparison and test functions

SYNOPSIS

``````#include <openssl/bn.h>

int BN_cmp(const BIGNUM *a, const BIGNUM *b);
int BN_ucmp(const BIGNUM *a, const BIGNUM *b);

int BN_is_zero(const BIGNUM *a);
int BN_is_one(const BIGNUM *a);
int BN_is_word(const BIGNUM *a, const BN_ULONG w);
int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w);
int BN_is_odd(const BIGNUM *a);

int BN_are_coprime(BIGNUM *a, const BIGNUM *b, BN_CTX *ctx);``````

DESCRIPTION

BN_cmp() compares the numbers a and b. BN_ucmp() compares their absolute values.

BN_is_zero(), BN_is_one(), BN_is_word() and BN_abs_is_word() test if a equals 0, 1, w, or |w| respectively. BN_is_odd() tests if a is odd.

BN_are_coprime() determines if a and b are coprime. ctx is used internally for storing temporary variables. The values of a and b and ctx must not be NULL.

RETURN VALUES

BN_cmp() returns -1 if a < b, 0 if a == b and 1 if a > b. BN_ucmp() is the same using the absolute values of a and b.

BN_is_zero(), BN_is_one() BN_is_word(), BN_abs_is_word() and BN_is_odd() return 1 if the condition is true, 0 otherwise.

BN_are_coprime() returns 1 if the BIGNUM's are coprime, otherwise it returns 0.

HISTORY

Prior to OpenSSL 1.1.0, BN_is_zero(), BN_is_one(), BN_is_word(), BN_abs_is_word() and BN_is_odd() were macros.

The function BN_are_coprime() was added in OpenSSL 3.1.