Novel side-channel attack on GPV signatures like Falcon

[Jaesang Noh]

Hello all,

We would like to share a novel side-channel attack targeting GPV signatures, especially Falcon, which is widely utilized in post-quantum cryptography (PQC). For a full description, please refer to our paper:  https://eprint.iacr.org/2024/2043. 

In brief, our proposed attack exploits Gaussian leakage and utilizes the ordinary least squares (OLS) regression scheme to recover the secret key. We have demonstrated that the proposed side-channel attack is consistent, meaning that the secret key can be recovered given a sufficient number of samples. When applied to Falcon, the proposed attack successfully recovers the lattice basis using 35,000 samples within 9 seconds. More precise results can be found in the table below, where SR indicates the success rate. This results a significant improvement in practicality and efficiency compared to recent Gaussian leakage-based attacks (learning slice scheme) which requires around 160,000 samples and 30 minutes. For detailed information regarding the proposed attack, please refer to the above link.



Additionally, the implementation code is available at the following GitHub repository: https://github.com/JaesangNoh-crypto/Falcon_recovery_OLSattack.

Thank you for reading.

Regards,

Jaesang Noh