Obfuscation of Abstract Data−Types
Stephen Drape · 2004
An obfuscation is a behaviour-preserving program transformation whose aim is to make a program “harder to understand”. Obfuscations are applied to make reverse engineering of a program more difficult. Two concerns about an obfuscation are whether it preserves behaviour (i.e. it is correct) and the degree to which it maintains efficiency. Obfuscations are applied mainly to object-oriented programs but constructing proofs of correctness for such obfuscations is a challenging task. It is desirable to have a workable definition of obfuscation which is more rigorous than the metric-based definition of Collberg et al. and overcomes the impossibility result of Barak et al. for their strong cryptographic definition. We present a fresh approach to obfuscation by obfuscating abstract datatypes allowing us to develop structure-dependent obfuscations that would otherwise (traditionally) not be available. We regard obfuscation as data refinement enabling us to produce equations for proving correctness and we model the datatype