Understanding Cryptographic Protocols: Secure Communication Techniques 🔐

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