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1. (WO2018219933) LIGHTWEIGHT DISPATCHER FOR PROGRAM CONTROL FLOW FLATTENING

Pub. No.:    WO/2018/219933    International Application No.:    PCT/EP2018/064043
Publication Date: Fri Dec 07 00:59:59 CET 2018 International Filing Date: Wed May 30 01:59:59 CEST 2018
IPC: G06F 21/14
Applicants: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Inventors: JOHANSSON, Björn
LANTZ, Patrik
LILJENSTAM, Michael
Title: LIGHTWEIGHT DISPATCHER FOR PROGRAM CONTROL FLOW FLATTENING
Abstract:
A method to obscure a control execution flow through a plurality of code blocks of a computer program includes initializing a state variable, q, and a switching variable, swVar, selecting a code block for execution using a present value of the switching variable, executing the code block, updating the state variable based on a present value of the state variable and a block-dependent constant, a_i, that is associated with the code block to generate an updated state variable, and by applying a state update function, g(q), to the updated state variable, and updating the switching variable by processing the state variable through a non-injective output function that generates a new value of the switching variable based on the state variable. The operations of selecting the code block, executing the code block, updating the state variable and updating the switching variable are repeated to control execution flow through at least a plurality of code blocks among the set of code blocks.