Method for making secure a 'smart card' instruction sequence for a data application system presented in the form of typed data recorded in a memory, the data application system uses a 'JAVA Language' virtual machine

摘要

Type data elements are recorded in second part (4,5) of a system (8) memory (1). Before executing instructions of a predetermined type, a method for continuos verification ensures that the type indicated by the instructions conforms to the expected type indicated by the data elements in the set memory (4,5), otherwise the execution is stopped. The method for making secure an instruction sequence of a data application system presented in the form of typed data recorded in a set first series of memory cells of a data system, in particular a system contained in a 'smart card'. The type data elements recorded in memory cells of the set second series (4,5) are in bi-specific correspondence with memory cells of the set first series (2,3) in which are recorded associated typed data, and whose configuration representative of one of the typed data types. The instructions being those of an application written in JAVA language. The typed data comprises typed data objects, and the data system integrates a software program called a JAVA virtual machine which manipulates the objects. The cells (2,3) of the first memory (1) set are organized in stacks having a maximum number at a set level. Each level comprises one of the memory cells. The typed objects are recorded in at least a first elementary stack called a data zone (2) and a second elementary stack called local variable zone (3). The type data elements are spread into two supplementary elementary stacks (4,5) in bi-specific relation with the first and second elementary piles so as to specify the type of the associated objects recorded in the data and local variable zones.