In this chapter: We will continue our discussion on Needham-Schroeder Protocol and will see how does it work, digital signature standard (DSS) and digital signature algorithm (DSA) will be discussed, we will talk about authentication applications, and will study kerberos which is an authentication service developed at MIT. | Network Security Lecture 24 Presented by: Dr. Munam Ali Shah Part – 2 (e): Incorporating security in other parts of the network Summary of the Previous Lecture In previous lecture we explored problems in message authentication We studied how digital signatures could be used to address message authentication problem. We talked about Direct Digital Signature and Arbitrated Digital signature. We also explored an example of message authentication protocol, ., Needham-Schroeder Protocol Outlines of today’s lecture We will continue our discussion on Needham-Schroeder Protocol and will see how does it work Digital Signature Standard (DSS) and Digital Signature Algorithm (DSA) will be discussed We will talk about authentication applications And will study Kerberos which is an authentication service developed at MIT Objectives You would be able to present an understanding of the higher level message authentication mechanism. You would be able demonstrate knowledge about different . | Network Security Lecture 24 Presented by: Dr. Munam Ali Shah Part – 2 (e): Incorporating security in other parts of the network Summary of the Previous Lecture In previous lecture we explored problems in message authentication We studied how digital signatures could be used to address message authentication problem. We talked about Direct Digital Signature and Arbitrated Digital signature. We also explored an example of message authentication protocol, ., Needham-Schroeder Protocol Outlines of today’s lecture We will continue our discussion on Needham-Schroeder Protocol and will see how does it work Digital Signature Standard (DSS) and Digital Signature Algorithm (DSA) will be discussed We will talk about authentication applications And will study Kerberos which is an authentication service developed at MIT Objectives You would be able to present an understanding of the higher level message authentication mechanism. You would be able demonstrate knowledge about different applications used for message authentication Recall the problem in message authentication Message authentication protect two parties from third party, will it protect two parties from each ?? Alice sends authenticated message to Bob (msg+MAC) Bob may forge a different message and claims that it comes from Alice Alice can deny sending the message to Bob later on hence include authentication function with additional capabilities The solution is Digital Signature and Authentication Protocols Authentication Protocols Used to convince parties of each other's identity and to exchange session keys May be one-way or mutual key issues of authenticated key exchange are confidentiality – to prevent masquerading and to protect session keys (secret or public key are used) timeliness – to prevent replay attacks Needham-Schroeder Protocol The term Needham–Schroeder protocol can refer to one of the two protocols intended for use over an insecure network, both proposed by Roger Needham and Michael Schroeder. .
