- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- NOTES
- SEE ALSO
- HISTORY
- COPYRIGHT

# 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 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.