International Association for Cryptologic Research

International Association
for Cryptologic Research


Quantifying the Security Cost of Migrating Protocols to Practice

Christopher Patton , University of Florida
Thomas Shrimpton , University of Florida
DOI: 10.1007/978-3-030-56784-2_4 (login may be required)
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Conference: CRYPTO 2020
Abstract: We give a framework for relating the quantitative, concrete security of a "reference'' protocol (say, one appearing in an academic paper) to that of some derived, "real'' protocol (say, appearing in a cryptographic standard). It is based on the indifferentiability framework of Maurer, Renner, and Holenstein (MRH), whose application has been exclusively focused upon non-interactive cryptographic primitives, e.g., hash functions and Feistel networks. Our extension of MRH is supported by a clearly defined execution model, and two composition lemmata, all formalized in a modern pseudocode language. Together, these allow for precise statements about game-based security properties of cryptographic objects (interactive or not) at various levels of abstraction, As a real-world application, we design and prove tight security bounds for a potential TLS 1.3 extension that integrates the SPAKE2 password-authenticated key-exchange into the existing handshake. (This is a problem of current interest to the IETF.)
Video from CRYPTO 2020
  title={Quantifying the Security Cost of Migrating Protocols to Practice},
  author={Christopher Patton and Thomas Shrimpton},