RSA_size.3ssl - Man Page

get RSA modulus size or security bits


 #include <openssl/rsa.h>

 int RSA_size(const RSA *rsa);

 int RSA_bits(const RSA *rsa);

 int RSA_security_bits(const RSA *rsa)


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



The RSA_bits() function was added in OpenSSL 1.1.0.

Referenced By

BN_num_bytes.3ssl(3), RSA_get0_key.3ssl(3), RSA_meth_new.3ssl(3), RSA_public_encrypt.3ssl(3).

The man pages RSA_bits.3ssl(3) and RSA_security_bits.3ssl(3) are aliases of RSA_size.3ssl(3).

2024-01-25 1.1.1q OpenSSL