Generation of reduced certificates in abstraction-carrying code

Abstraction-Carrying Code (ACC) has recently been proposed as a framework for mobile code safety in which the code supplier provides a program together with an abstraction whose validity entails compliance with a predeflned safety policy. The abstraction plays thus the role of safety certiflcate and its generation is carried out automatically by a flxed-point analyzer. The advantage of providing a (flxed- point) abstraction to the code consumer is that its validity is checked in a single pass of an abstract interpretation-based checker. A main challenge is to reduce the size of certiflcates as much as possible while at the same time not increasing checking time. In this paper, we flrst introduce the notion of reduced certiflcate which characterizes the subset of the abstraction which a checker needs in order to validate (and re-construct) the full certiflcate in a single pass. Based on this notion, we then instrument a generic analysis algorithm with the necessary extensions in order to identify the information relevant to the checker.