Types and Effects for Asymmetric Cryptographic Protocols

MSR-TR-2002-31 |

15th IEEE Computer Security Foundations Workshop (CSFW 2002)

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We present the first type and effect system for proving authenticity properties of security protocols based on asymmetric cryptography. The most significant new features of our type system are: (1) a separation of public types (for data possibly sent to the opponent) from tainted types (for data possibly received from the opponent) via a subtype relation; (2) trust effects, to guarantee that tainted data does not, in fact, originate from the opponent; and (3) challenge/response types to support a variety of idioms used to guarantee message freshness. We illustrate the applicability of our system via protocol examples.