NAME

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

SYNOPSIS

#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);

DESCRIPTION

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.

RETURN VALUES

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.

SEE ALSO

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

HISTORY

BN_add_word() and BN_mod_word() are available in all versions of SSLeay and OpenSSL. BN_div_word() was added in SSLeay 0.8, and BN_sub_word() and BN_mul_word() in SSLeay 0.9.0. Before 0.9.8a, the return value for BN_div_word() and BN_mod_word() in case of an error was 0.