fix: remove references to 2^-64 pfail for GPU

This commit is contained in:
Nicolas Sarlin
2025-07-25 18:03:31 +02:00
committed by Nicolas Sarlin
parent 543517cea5
commit b9d75c9f8f
4 changed files with 3 additions and 6 deletions

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@@ -201,11 +201,9 @@ When a new update is published in the Lattice Estimator, we update parameters ac
### Security model
By default, the parameter sets used in the High-Level API with the x86 CPU backend have a failure probability $\le 2^{128}$ to securely work in the IND-CPA^D model using the algorithmic techniques provided in our code base [1].
By default, the parameter sets used in the High-Level API have a failure probability $\le 2^{-128}$ to securely work in the IND-CPA^D model using the algorithmic techniques provided in our code base [1].
If you want to work within the IND-CPA security model, which is less strict than the IND-CPA-D model, the parameter sets can easily be changed and would have slightly better performance. More details can be found in the [TFHE-rs documentation](https://docs.zama.ai/tfhe-rs).
The default parameters used in the High-Level API with the GPU backend are chosen considering the IND-CPA security model, and are selected with a bootstrapping failure probability fixed at $p_{error} \le 2^{-128}$. In particular, it is assumed that the results of decrypted computations are not shared by the secret key owner with any third parties, as such an action can lead to leakage of the secret encryption key. If you are designing an application where decryptions must be shared, you will need to craft custom encryption parameters which are chosen in consideration of the IND-CPA^D security model [2].
[1] Bernard, Olivier, et al. "Drifting Towards Better Error Probabilities in Fully Homomorphic Encryption Schemes". https://eprint.iacr.org/2024/1718.pdf
[2] Li, Baiyu, et al. "Securing approximate homomorphic encryption using differential privacy." Annual International Cryptology Conference. Cham: Springer Nature Switzerland, 2022. https://eprint.iacr.org/2022/816.pdf