Grammatical Inference and Language Frameworks for LANGSEC

Dr. Kerry N. Wood, Dr. Richard E. Harang
2015 2015 IEEE Security and Privacy Workshops  
Formal Language Theory for Security (LANGSEC) has proposed that formal language theory and grammars be used to define and secure protocols and parsers. The assumption is that by restricting languages to lower levels of the Chomsky hierarchy, it is easier to control and verify parser code. In this paper, we investigate an alternative approach to inferring grammars via pattern languages and elementary formal system frameworks. We summarize inferability results for subclasses of both frameworks
more » ... discuss how they map to the Chomsky hierarchy. Finally, we present initial results of pattern language learning on logged HTTP sessions and suggest future areas of research. Keywords-grammatical inference, LANGSEC, language identification, pattern language, elementary formal system (EFS) Inferable The framework should have a learning algorithm that takes input strings from examples, produces a grammar or similar structure, and has tractable complexity. Applicable Otherwise known as membership queries. Given a string, can it be efficiently (polynomial time) determined if the string is a member of the target language? Map to Chomsky The framework should have classes or subclasses that map to the Chomsky hierarchy, thus allowing for the computational limiting argument mentioned previously.
doi:10.1109/spw.2015.17 dblp:conf/sp/WoodH15 fatcat:paiqhvsx6vcifc7f6vzkurbbl4