Abstract: A method for parsing and executing a software program includes receiving a portion of a software program in an original linguistic form, wherein the portion of the software program includes a nonlinear program element having a body, and, while retaining the original linguistic form, directly executing the nonlinear program element by manipulating a parse state and an input stream of tokens representing the body of the nonlinear program element, wherein directly executing comprises executing tokens until the dynamic end of the nonlinear program element is reached. A system includes a tokenizer operable to tokenize the software program and a parser operable to directly execute a nonlinear program element in the software program by manipulating a parse state and an input stream of tokens representing the body of the nonlinear program element, while preserving the original linguistic form of the software program.

Abstract: Systems and methods for disrupting the operational capabilities and the distribution capabilities of computer viruses are provided. According to one embodiment, an execution environment is created that makes a computer system appear unique to incoming viruses. Responsive to installation of a valid program, the program is registered for execution by transforming it from an executable form into a locally unique form based on a diversity mechanism. Responsive to detecting an attempted execution of a program and prior to execution of the program, it is transformed by causing a protected pre-execution process of the computer system, which implements the diversity mechanism in the form of an inverse transform, to be applied. If the program was previously validly registered, then the transformation based on the diversity mechanism results in an executable program that will execute properly on the computer system; otherwise the transformation results in an executable program that will fail to correctly execute.