Et tu, Brute? SCA Assisted CCA using Valid Ciphertexts - A Case Study on HQC KEM

ePrint Report: Et tu, Brute? SCA Assisted CCA using Valid Ciphertexts - A Case Study on HQC KEM

Thales Paiva, Prasanna Ravi, Dirmanto Jap, Shivam Bhasin

HQC is a code-based key encapsulation mechanism (KEM) that was selected to move to the fourth round of the NIST post-quantum standardization process. While this scheme was previously targeted by side-channel assisted chosen-ciphertext attacks for key recovery, we notice that all of these attacks use malformed ciphertexts, which can be easily detected since they …

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