NAME

       BN_security_bits - returns bits of security based on given numbers

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 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>.

3.0.13                                             2025-09-18                             BN_SECURITY_BITS(3SSL)