Breaking DPA-Protected Kyber via the Pair-Pointwise Multiplication

Published in Preprint / Work in Progress, 2023

This work presents a novel side-channel template attack on the Kyber Key Encapsulation Mechanism, targeting the pair-pointwise multiplication step used in the decapsulation process.

Main contributions:

  • Exploits leakage from isolated coefficient multiplications in NTT domain, even in DPA-masked implementations
  • Effective against shuffling countermeasures
  • Works with known ciphertexts, not only chosen ones
  • Demonstrates success via Hamming weight simulations and template difference analysis
  • Suggests that masking and shuffling alone are insufficient for lattice-based schemes like Kyber

The simplicity and generality of the attack show the urgent need for more robust countermeasures against side-channel vulnerabilities in post-quantum cryptographic implementations.