leanEA. A poor man\u27s evolving algebra compiler

The Prolog program term_expansion((define C as A with B), (C=>A:-B,!)). term_expansion((transition E if C then D), ((transition E):-C,!,B,A,(transition _))) :- serialize(D,B,A). serialize((E,F),(C,D),(A,B)) :- serialize(E,C,B), serialize(F,D,A). serialize(F:=G, ([G]=>*[E],F=..[

Implementing semantic tableaux

This report describes implementions of the tableau calculus for first-order logic. First an extremely simple implementation, called leanTAP, is presented, which nonetheless covers the full functionality of the calculus and is also competitive with respect to performance. A second approach uses compilation techniques for proof search. Improvements inculding universal variables and lemmata are considered as well as more efficient data structures using reduced ordered binary decision diagrams. The implementation language is PROLOG. In all cases fully operational PROLOG code is given. For leanTAP a formal proof of the correctness of the implementation is given relying on the operational semantics of PROLOG as given by the SLD-tree model. This report will appear as a chapter in the Handbook of Tableau-based Methods in Automated Deduction edited by: D. Gabbay, M. D\u27Agostino, R. H\"{a}hnle, and J.Posegga published by: KLUWER ACADEMIC PUBLISHERS Electronic availability will be discontinued after final acceptance for publication is obtained

On Structural Signatures for Tree Data Structures

Abstract. In this paper, we present new attacks on the redactable signature scheme introduced by Kundu and Bertino at VLDB '08. This extends the work done by Brzuska et al. at ACNS '10 and Samelin et al. at ISPEC '12. The attacks address unforgeability, transparency and privacy. Based on the ideas of Kundu and Bertino, we introduce a new provably secure construction. The corresponding security model is more flexible than the one introduced by Brzuska et al. Moreover, we have implemented schemes introduced by Brzuska et al. and Kundu and Bertino. The evaluation shows that schemes with a quadratic complexity become unuseable very fast

leanEA: A Poor Man's Evolving Algebra Compiler

The Prolog program "termexpansion((define C as A with B), (C=?A:-B,!)). termexpansion((transition E if C then D), ((transition E):-C,!,B,A,(transition ))) :- serialize(D,B,A). serialize((E,F),(C,D),(A,B)) :- serialize(E,C,B), serialize(F,D,A). serialize(F:=G, ([G]=?*[E],F=..[C---D],D=?*B,A=..[C---B]), asserta(A=?E)). [G---H]=?*[E---F] :- (G="E; G=..[C---D],D=?*B,A=..[C---B],A=?E), !,H=?*F. []=?*[]. A=?B :- [A,B]=?*[D,C], D==C." implements a virtual machine for evolving algebras. It offers an efficient and very flexible framework for their simulation

Smartcard Firewalls Revisited

Smartcards are being used as secure endpoints in computer transactions. Recently, the connectivity of smartcards has increased and future smartcards will be able to communicate over the TCP/IP protocol