Correcting the modulus switch error in TFHE bootstrapping for real-valued computation

본문 미리보기

Torus Fully Homomorphic Encryption (TFHE) enables the homomorphic evaluation of arbitrary functions via Programmable Bootstrapping (PBS). However, the modulus switching step inherent to bootstrapping introduces a rounding error that forces the discretization of the input space, limiting the achievable precision on real-valued inputs. We propose a correction algorithm based on a first-order Taylor expansion, applied after bootstrapping, that directly mitigates this rounding error. Our meth