Which of the following statements about MD5 Routing Updates authentication is valid？ （）

• A、The MD5 algorithm inputs the routing updates of arbitrary length and outputs a 128-bit hash
• B、The MD5 algorithm inputs the routing updates of every 64bit length and outputs an 8-bit hash
• C、Multiple keys are supported
• D、Routing updates packets are delivered in encrypted messages
• E、Shared secret keys are delivered in encrypted messages