BN_add_word, BN_sub_word, BN_mul_word, BN_div_word, BN_mod_word - arithmetic functions on BIGNUMs with integers

#include <openssl/bn.h>

int BN_add_word(BIGNUM *a, BN_ULONG w);

int BN_sub_word(BIGNUM *a, BN_ULONG w);

int BN_mul_word(BIGNUM *a, BN_ULONG w);

BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w);

BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);

These functions perform arithmetic operations on BIGNUMs with unsigned integers. They are much more efficient than the normal BIGNUM arithmetic operations.

BN_add_word() adds w to a ("a+=w").

BN_sub_word() subtracts w from a ("a-=w").

BN_mul_word() multiplies a and w ("a*=w").

BN_div_word() divides a by w ("a/=w") and returns the remainder.

BN_mod_word() returns the remainder of a divided by w ("a%w").

For BN_div_word() and BN_mod_word(), w must not be 0.

BN_add_word(), BN_sub_word() and BN_mul_word() return 1 for success, 0 on error. The error codes can be obtained by ERR_get_error(3).

BN_mod_word() and BN_div_word() return a%w on success and (BN_ULONG)-1 if an error occurred.

ERR_get_error(3), BN_add(3)

Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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

2021-03-25 1.1.1k