Updated: 2021/Apr/14


BN_security_bits(3)                 OpenSSL                BN_security_bits(3)



NAME
       BN_security_bits - returns bits of security based on given numbers

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/bn.h>

        int BN_security_bits(int L, int N);

DESCRIPTION
       BN_security_bits() returns the number of bits of security provided by a
       specific algorithm and a particular key size. The bits of security is
       defined in NIST SP800-57. Currently, BN_security_bits() support two
       types of asymmetric algorithms: the FFC (Finite Field Cryptography) and
       IFC (Integer Factorization Cryptography). For FFC, e.g., DSA and DH,
       both parameters L and N are used to decide the bits of security, where
       L is the size of the public key and N is the size of the private key.
       For IFC, e.g., RSA, only L is used and it's commonly considered to be
       the key size (modulus).

RETURN VALUES
       Number of security bits.

NOTES
       ECC (Elliptic Curve Cryptography) is not covered by the
       BN_security_bits() function. The symmetric algorithms are not covered
       neither.

SEE ALSO
       DH_security_bits(3), DSA_security_bits(3), RSA_security_bits(3)

HISTORY
       The BN_security_bits() function was added in OpenSSL 1.1.0.

COPYRIGHT
       Copyright 2017-2019 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
       <https://www.openssl.org/source/license.html>.



1.1.1i                            2019-06-09               BN_security_bits(3)