Probability to meet in the middle

Abstract

This paper proposes "Matching Models A, B, and C" for the meet-in-the-middle attacks against a message with digital signature to provide a more sound foundation for the calculation of the probability of success. The typical procedures by Yuval and by Merkle are regarded as Model A or "birthday paradox in two groups," and are different from the classical birthday paradox. Models B and C are applicable for other similar procedures. The relationship of Matching Models and probabilistic models for testing the algebraic structure of DES is also discussed. © 1990 International Association for Cryptologic Research.