Operating Systems: Concurrent and Distributed Software Design

8.5. Protocols

We now show how the styles of algorithm described above can be used in practice in distributed systems. In order to communicate securely the participants must agree to follow a protocol. A convention has arisen for naming the parties involved in security protocols. When two parties are involved they are called Alice and Bob. Participants three and four, if they exist, are named Carol and Dave. We are concerned with various threats and Eve is the name of an eavesdropper, Mallet is a malicious attacker with computing resources at his disposal and Trent is a trusted third party or arbiter. In some cases we will name a Server. We give a selection of basic protocols and assume in each case that a cryptosystem has been agreed in advance ...