Repository navigation
Conversation
Fixes google#880. The existing secret-key lowering of `lwe.rlwe_encrypt` produced `(u, u*s + m + e)` with a ternary `u`, which does not decrypt correctly. It now produces `(m + t*e - a*s, a)` where the mask `a` is sampled uniformly from R_Q and the noise is scaled by the plaintext modulus `t`, as in the public-key path. The coefficients of `a` are sampled with `random.sample_modq` (which samples each RNS limb uniformly). The `lwe.rlwe_decrypt` lowering is also fixed to compute `c0 + c1*s`, matching the LWE dialect's ciphertext convention and the existing public-key encryption; it previously computed `s*c0 + c1`. I was on paternity leave when this was implemented so I'm not sure what happened there. Both lowerings implement BGV-style (`lsb`) encryption only, so they now emit an error for `msb` (BFV) and `mix` (CKKS) ciphertexts rather than silently lowering them with BGV semantics. PiperOrigin-RevId: 1013039909
j2kun
marked this pull request as draft
November 5, 2026 23:27
j2kun
force-pushed
the
rlwe_encrypt_ckks
branch
from
November 5, 2026 23:42
e9ea605 to
2f68014
Compare
The `mix` encryption type was only ever used for CKKS ciphertexts, and nothing used it. Renamed it to `ckks` and documented what each encryption type decrypts to, since `lsb`, `msb`, and `ckks` differ in how the message and noise are scaled at encryption time.
j2kun
force-pushed
the
rlwe_encrypt_ckks
branch
from
November 5, 2026 23:45
2f68014 to
5e6d9a7
Compare
Extend the lowering of `lwe.rlwe_encrypt` (secret and public key) and `lwe.rlwe_decrypt` to `ckks` ciphertexts. CKKS shares the same decryption circuit with BGV (c_0 + c_1 * s), and it differs only in that BGV scales the encryption noise by the plaintext modulus `t` while CKKS does not, so whether to add a noise scale is derived from the encryption type enum.
j2kun
force-pushed
the
rlwe_encrypt_ckks
branch
from
November 6, 2026 03:10
5e6d9a7 to
9f55487
Compare
This branch has not been deployed
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Includes #3597 as a base