Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language ARSPA’05 Workshop, Lisbon, 16 July 2005 Alexey Gotsman joint work with Fabio Massacci and Marco Pistore University of Trento (Italy) {gotsman, massacci, pistore}@dit.unitn.it http://www.dit.unitn.it/˜{gotsman, massacci, pistore} Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 1/25
About the Talk � An algorithm for the translation of security protocol � About the Talk � Outline speci fi cations in a subset of the HLPSL speci fi cation � Motivation � Proposed Approach language to the applied pi calculus � HLPSL Language � An independent semantics of HLPSL � Applied Pi Calculus � Translation Algorithm � A way to verify HLPSL speci fi cations through a process � Semantical Issues � Experimental Results algebra � Conclusions � Future Work Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 2/25
Outline 1. Motivation and an outline of the proposed approach � About the Talk � Outline 2. Description of HLPSL and the applied pi calculus � Motivation � Proposed Approach � HLPSL Language 3. Main ideas underlying the translation algorithm � Applied Pi Calculus � Translation Algorithm 4. Semantical issues arising in connection with the translation � Semantical Issues � Experimental Results 5. Experimental results � Conclusions � Future Work Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 3/25
A Protocol Formalization Pitfall � Informal speci fi cation languages: � About the Talk � Outline � Security research papers and standard bodies � Motivation � Proposed Approach � Formal languages: � HLPSL Language � Applied Pi Calculus � Experts in formal veri fi cation � Translation Algorithm � Semantical Issues � Problem: The gaps between these can lead to � Experimental Results � Conclusions misunderstandings in the meaning of the protocol and its � Future Work goals � Solution: Using formal protocol speci fi cation languages Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 4/25
Security Protocol Speci fi cation Languages � ALSP � About the Talk � Outline � BRUTUS � Motivation � Proposed Approach � CAPSL and CIL � HLPSL Language � Applied Pi Calculus � Translation Algorithm � CASPER � Semantical Issues � Experimental Results � CVS � Conclusions � Future Work � HLPSL � NAPTRL � Spi calculus-based (e. g. ProVerif) � Many languages but no “dominant” one � Languages are too tied to back-ends? Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 5/25
HLPSL Advantages � Independently motivated semantics (Lamport’s temporal � About the Talk � Outline logic of actions) � Motivation � Proposed Approach � Veri fi cation of HLPSL speci fi cations (AVISPA tool): � HLPSL Language � Applied Pi Calculus � SATMC – bounded model checking and satis fi ability � Translation Algorithm � Semantical Issues � OFMC – on-the- fl y model checking � Experimental Results � Conclusions � CL-AtSe – term rewriting � Future Work � TA4SP – abstraction-based veri fi cation � ? – process algebras Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 6/25
Proposed Approach and Its Outcomes � Translation of speci fi cations in a subset of HLPSL to a � About the Talk � Outline process algebra � Motivation � Proposed Approach � The dialect of the applied pi calculus supported by the � HLPSL Language � Applied Pi Calculus ProVerif tool � Translation Algorithm � Semantical Issues � Translation algorithm lets us verify protocols speci fi ed in � Experimental Results � Conclusions HLPSL with the ProVerif tool � Future Work � It completes the formalisms available for HLPSL � Translation algorithm provides an independent semantics of HLPSL � It can be used to clarify ambiguities in speci fi cations of HLPSL Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 7/25
Veri fi cation Scheme � About the Talk � Outline � Motivation � Proposed Approach � HLPSL Language � Applied Pi Calculus � Translation Algorithm � Semantical Issues � Experimental Results � Conclusions � Future Work Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 8/25
HLPSL – Role Speci fi cations � Protocol speci fi cations are divided into roles � About the Talk � Outline � Basic roles � Motivation � Proposed Approach � Actions of one kind of participant: � HLPSL Language � Applied Pi Calculus � parameters � Translation Algorithm � Semantical Issues � initial state � Experimental Results � Conclusions � transitions � Future Work � Composed roles � Role instantiations joined together Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 9/25
HLPSL – Transitions � Transitions: ev =|> act � About the Talk � Outline � trigger event ev � Motivation � Proposed Approach � action act � HLPSL Language � Applied Pi Calculus � Events: � Translation Algorithm � Semantical Issues � comparisons of expressions � Experimental Results � Conclusions � receiving of messages � Future Work � Actions: � assignments to variables � sending of messages � The communication is synchronous and takes place over channels � HLPSL allows for modeling protocols with non-linear structure Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 10/25
HLPSL – Goals � Goals: � About the Talk � Outline � secrecy: � Motivation � Proposed Approach secrecy_of m � HLPSL Language � weak authentication: � Applied Pi Calculus � Translation Algorithm � Semantical Issues Alice weakly authenticates Bob on p � Experimental Results � Conclusions ( wrequest(b,a,p,m) , witness(a,b,p,m) ) � Future Work � strong authentication: Alice authenticates Bob on p � Each goal corresponds to a temporal formula � Goal facts: � secret(m,a) � witness(a,b,p,m) � wrequest(a,b,p,m) � request(a,b,p,m) Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 11/25
HLPSL – An Example (1) : � About the Talk (1) A → B { Na, A } Kb � Outline : (2) B → A { Na, Nb } Ka � Motivation � Proposed Approach : (3) A → B { Nb } Kb � HLPSL Language � Applied Pi Calculus � Translation Algorithm � Semantical Issues � Experimental Results role Alice (A,B : agent, Ka,Kb : public_key, � Conclusions Snd,Rcv : channel (dy)) played by A def= � Future Work local State : nat, Na : text (fresh), Nb : text init State = 0 accept State = 2 transition 1. State = 0 /\ Rcv(start) =|> Snd({A.Na’}Kb) /\ State’ = 1 /\ witness(A,B,na,Na’) /\ secret(Na’,A) /\ secret(Na’,B) 2. State = 1 /\ Rcv({Na.Nb’}Ka) =|> Snd({Nb’}Kb) /\ State’ = 2 /\ wrequest (A,B,nb,Nb’) end role Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 12/25
HLPSL – An Example (2) � About the Talk role Session (A,B: agent, Ka,Kb : public_key, � Outline SA,RA,SB,RB : channel(dy)) def= � Motivation � Proposed Approach composition � HLPSL Language Alice (A,B,Ka,Kb,SA,RA) /\ � Applied Pi Calculus Bob (B,A,Kb,Ka,SB,RB) � Translation Algorithm end role � Semantical Issues � Experimental Results role Environment() def= � Conclusions � Future Work const a,b,i : agent, ka,kb,ki : public_key, sa1,ra1,sb1,rb1,sa2,ra2,sb2,rb2 : channel(dy), na,nb : protocol_id knowledge (i) = {a,b,i,ka,kb,ki,inv(ki)} composition Session(a,b,ka,kb,sa1,ra1,sb1,rb1) /\ Session(a,i,ka,ki,sa2,ra2,sb2,rb2) end role goal Alice weakly authenticates Bob on na Bob weakly authenticates Alice on nb secrecy_of Na, Nb end goal Alexey Gotsman, Fabio Massacci, Marco Pistore Towards an Independent Semantics and Veri fi cation Technology for the HLPSL Speci fi cation Language - p. 13/25
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