Importance

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Abstract

A method and system for transforming and verifying downloaded programs fragments with data type restriction in an embedded system in which a program fragment being temporarily stored a verification process of the stored program fragment object code is executed instruction by instruction so as to discriminate for each instruction the existence of a target, a branching instruction target, a target of an exception handler call or a target of a subroutine call. On the occurrence of a target of a branching instruction as the current instruction, the empty status of the stack is verified and the program fragment is rejected otherwise. A verification process and updating of the effect of the current instruction on the data types of the type stack and the table of register types is performed. The verification process is successfully executed instruction by instruction until the table of register types is stable, with no modification being present, and interrupted with the program fragment being rejected otherwise.

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First Claim