Secure Implementation of Cryptographic Protocols: A Case Study of Mutual Distrust

Security protocols are critical for protecting modern communication infrastructures and are therefore subject to thorough analysis. However practical implementations of these protocols lack the same level of attention and thus may be more exposed to attacks. This paper discusses security assurance provided by security-typed languages when implementing cryptographic protocols. Our results are based on a case study using Jif, a Java-based security-typed language, for implementing a non-trivial cryptographic protocol that allows playing online poker without a trusted third party. The case study deploys the largest program written in a security-typed language to date and identifies insights ranging from security guarantees to useful patterns of secure programming.