# Types of internal certificate authorities

The internal certificate authority can be either an internal Elliptic Curve Digital Signature Algorithm (ECDSA) certificate authority or an internal RSA certificate authority.

ECDSA is a digital signature algorithm that uses elliptic curve cryptography. Using an internal ECDSA certificate authority enables 256-bit encryption on the Management Server for connections between the Management Server and NGFW Engines.

You can only use one type of internal certificate authority at a time.