Updated: 2021/Apr/14


RSA_size(3)                         OpenSSL                        RSA_size(3)



NAME
       RSA_size, RSA_bits, RSA_security_bits - get RSA modulus size or
       security bits

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/rsa.h>

        int RSA_size(const RSA *rsa);

        int RSA_bits(const RSA *rsa);

        int RSA_security_bits(const RSA *rsa)

DESCRIPTION
       RSA_size() returns the RSA modulus size in bytes. It can be used to
       determine how much memory must be allocated for an RSA encrypted value.

       RSA_bits() returns the number of significant bits.

       rsa and rsa->n must not be NULL.

       RSA_security_bits() returns the number of security bits of the given
       rsa key. See BN_security_bits(3).

RETURN VALUES
       RSA_size() returns the size of modulus in bytes.

       DSA_bits() returns the number of bits in the key.

       RSA_security_bits() returns the number of security bits.

SEE ALSO
       BN_num_bits(3)

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

COPYRIGHT
       Copyright 2000-2018 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                            2019-03-12                       RSA_size(3)