NAME

SYNOPSIS

 #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);

DESCRIPTION

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.

RETURN VALUES

All other functions return 1 for success, 0 on error. The error codes can be obtained by ERR_get_error(3).

SEE ALSO

COPYRIGHT

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 <https://www.openssl.org/source/license.html>.