Runtime Code Generation for Constant-Time Secret-Indexed Array Accesses: Applications to PERK and NTRU

This chapter introduces a groundbreaking method for secure cryptographic implementations by utilizing runtime code generation to achieve constant-time array accesses. The approach effectively eliminates vulnerabilities to side-channel attacks, which exploit physical information leaked during cryptographic operations. By leveraging the CPU’s register file as temporary storage for arrays, the method ensures that memory accesses do not leak sensitive information through cache-based side-channel attacks. The chapter demonstrates the application of this technique to various cryptographic operations, including permutation sampling, composition, and inversion, which are crucial in post-quantum schemes like PERK and NTRU. Performance results show significant improvements over existing constant-time alternatives, making this method a promising solution for enhancing both the security and efficiency of cryptographic implementations. The chapter also discusses the limitations and potential issues of the technique, encouraging further research to assess and develop workarounds. Overall, this innovative approach offers a robust solution for securing cryptographic implementations against side-channel attacks, providing a valuable resource for professionals in the field.