Acta Informatica

, 48:317 | Cite as

CHAP and rewrite components

  • Sándor Vágvölgyi
Original Article


We present an additional feature to the Challenge Handshake Authentication Protocol. It makes the protocol resilient to offline brute-force/dictionary attacks. We base our contribution to the protocol on the concept of a rewrite complement for ground term rewrite systems (GTRSs). We also introduce and study the notion of a type-based complement which is a special case of a rewrite complement. We show the following decision results. Given GTRSs A, C, and a reduced GTRS B over some ranked alphabet Σ, one can decide whether C is a type-based complement of A for B. Given a GTRS A and a reduced GTRS B over some ranked alphabet Σ, one can decide whether there is a GTRS C such that C is a type-based complement of A for B. If the answer is yes, then we can construct such a GTRS C.


Identity Relation Direct Inspection Ground Term Reduction Sequence Tree Automaton 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.Department of Foundations of Computer ScienceUniversity of SzegedSzegedHungary

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