19.4 Cryptographic protocol

Module19 – Cryptography, Section 19.4 – Cryptographic protocol. Cryptographic protocol applies cryptographic methods and describes how the algorithms should be used and some aspects are: – Key agreement or establishment – Entity authentication – Symmetric encryption and message authentication material construction – Secured application-level data transport – Non-repudiation methods – Secret sharing methods – Secure multi-party computation Crypto Protocols • Internet Key Exchange (IKE) • IPSec (Internet Protocol Security) • Kerberos • Off-the-Record Messaging (OTR) • Point to Point Protocol (PPP) • Signal Protocol • Transport Layer Security (TLS) • ZRTP (Z and Real-time Transport Protocol) TLS is a cryptographic protocol that is used to secure web (HTTP/HTTPS) connections. TLS is used in applications such as web browsing, email, Internet faxing, instant messaging, and voice-over-IP (VoIP). The 3 aspects of TLS are: • It has an entity authentication mechanism, based on the X.509 system. • A key setup phase, where a symmetric encryption key is formed by employing public-key cryptography. • An application-level data transport function. Cryptographic protocols can be verified formally to identify threats and done through below models: • Dolev–Yao model • Burrows–Abadi–Needham logic (BAN logic) • Protocol composition logic (PCL) • Strand space • Alice & Bob notation Projects and tools for Security protocol verification – AVISPA and AVANTSSAR – Casper / FDR compiler – CryptoVerif, ProVerif – Cryptographic Protocol Shapes Analyzer (CPSA) – Knowledge In Security protocolS (KISS) – Maude-NRL Protocol Analyzer (Maude-NPA) – Scyther – Tamarin Prover