BN_set_bit, BN_clear_bit, BN_is_bit_set, BN_mask_bits, BN_lshift, BN_lshift1,
BN_rshift, BN_rshift1 - bit operations on BIGNUMs
#include <openssl/bn.h>
int BN_set_bit(BIGNUM *a, int n);
int BN_clear_bit(BIGNUM *a, int n);
int BN_is_bit_set(const BIGNUM *a, int n);
int BN_mask_bits(BIGNUM *a, int n);
int BN_lshift(BIGNUM *r, const BIGNUM *a, int n);
int BN_lshift1(BIGNUM *r, BIGNUM *a);
int BN_rshift(BIGNUM *r, BIGNUM *a, int n);
int BN_rshift1(BIGNUM *r, BIGNUM *a);
BN_set_bit() sets bit
n in
a to 1
("a|=(1<<n)"). The number is expanded if necessary.
BN_clear_bit() sets bit
n in
a to 0
("a&=~(1<<n)"). An error occurs if
a is shorter
than
n bits.
BN_is_bit_set() tests if bit
n in
a is set.
BN_mask_bits() truncates
a to an
n bit number
("a&=~((~0)<<n)"). An error occurs if
a already is
shorter than
n bits.
BN_lshift() shifts
a left by
n bits and places the result
in
r ("r=a*2^n"). Note that
n must be nonnegative.
BN_lshift1() shifts
a left by one and places the result in
r ("r=2*a").
BN_rshift() shifts
a right by
n bits and places the result
in
r ("r=a/2^n"). Note that
n must be nonnegative.
BN_rshift1() shifts
a right by one and places the result in
r ("r=a/2").
For the shift functions,
r and
a may be the same variable.
BN_is_bit_set() returns 1 if the bit is set, 0 otherwise.
All other functions return 1 for success, 0 on error. The error codes can be
obtained by
ERR_get_error(3).
BN_num_bytes(3),
BN_add(3)
Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (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
<
https://www.openssl.org/source/license.html>.