We can make valid ciphertexts where the sampled $u, e_1, e_2$ are all set to zero. This would allow for fhe_var! created variables to be legitimate Cipher nodes while still being deterministic, and allow us to remove the Indeterminate, Stage, etc. types from crate::types::intern::fhe_program_node (added in #272).
It looks like this would require factoring seal::util::rlwe::encrypt_zero_asymmetric to support accepting these values, rather than always generating them via parms.random_generator()->create();.
Additionally, we should ensure that SEAL_THROW_ON_TRANSPARENT_CIPHERTEXT is set to false, since there are a number of checks to ensure that these values are not zero. E.g. here.
However, it would be good to expose that is_transparent() method and call it in the Cipher::output implementation as a safeguard for the user not to return transparent ciphertexts from an FHE program.
We can make valid ciphertexts where the sampled$u, e_1, e_2$ are all set to zero. This would allow for
fhe_var!created variables to be legitimateCiphernodes while still being deterministic, and allow us to remove theIndeterminate, Stage, etc. types fromcrate::types::intern::fhe_program_node(added in #272).It looks like this would require factoring
seal::util::rlwe::encrypt_zero_asymmetricto support accepting these values, rather than always generating them viaparms.random_generator()->create();.Additionally, we should ensure that
SEAL_THROW_ON_TRANSPARENT_CIPHERTEXTis set to false, since there are a number of checks to ensure that these values are not zero. E.g. here.However, it would be good to expose that
is_transparent()method and call it in theCipher::outputimplementation as a safeguard for the user not to return transparent ciphertexts from an FHE program.