Devices and methods for protecting cryptographic programs

Abstract

There is provided a device for protecting a cryptographic program implemented in a cryptographic computing device, the cryptographic computing device includes one or more processors, the cryptographic program comprising instructions and being associated with an initial execution order of the instructions. The device comprises a compiler to compile the cryptographic program, which provides an intermediate representation of the cryptographic program comprising instructions and variables used to execute the instructions. The device is configured to: determine a graph of dependencies comprising nodes and edges, each node of the graph representing an instruction of the intermediary representation, and each edge of the graph representing a variable of the intermediary representation; mask the graph of dependencies by replacing each variable of the graph of dependencies with a masked variable, the processing unit determining the masked variable by applying a masking scheme to the variable, which provides a masked graph of dependencies; determine at least a set of independent instructions using the masked graph of dependencies; determine an execution order for each set of independent instructions from the initial execution order, the execution order representing the order of execution of the set of independent instructions by at least one of the one or more processors.