Practical TFHE Ciphertext Sanitization for Oblivious Circuit Evaluation

Homomorphic encryption (FHE) enables the computation of arbitrary circuits over encrypted data. A widespread application of HE is oblivious circuit evaluation, where a sender evaluates its private circuit over a receiver's encrypted data, covering scenarios such as oblivious inference and oblivious PRF protocols. However, while the security of HE guarantees the receiver's privacy against the sender, the privacy of the sender's circuit is not solely derived from the security of HE.