control and protected databases. CODA has a mechanism for securely authorizing clients to servers, servers to clients and setting up encrypted channels between them. The CODA users password is a key element in this. The authentication and encryption systems are very close to those used by Kerberos 5. Since another member of the class is covering Kerberos I will be brief in its discussion. The key points are shared secret cryptography, establishing secure connections and authentication protocol. The shared secret cryptography is achieved by assuming in numerous places that the server and client on a connection share a secret key allowing the sender to encrypt data and the receiver to decrypt it. There are three methods currently in place to acquire the key. The first is upon authentication the server and the client can share a password to establish a secure connection. CODA employs a program to look up the user name in /password and attempts a secure connection with the server using the clients username as its ID and the password. It then executes a bind request with the server. The second is in the final stages of authentication the server can send the client a session key. The third involves Venus and the server using the session key from the authentication protocol to establish a secure connection. Establishing a secure connection requires the two parties to share the secret key and a public client ID. As of right now the CODA developers are attempting to get Kerberos to better work with CODA. They are also attempting to plug a few other security holes. The most serious of these holes is the need for authenticated connections on the callbacksCurrent StatusCODA has been in use at Carnegie Melon University since the early 1990s and over the years it has yet to lose any user data. At times servers have failed, but the replication of all volumes has insured against any data loss. A new disk is inserted and then updated i...
