Switch-and-Squash executor

Description

Library crate

Upon receiving a notification, it mainly does the following steps:

• Fetches (handle, compressed_ct) pairs from pbs_computations and ciphertexts tables.
• Computes large_ct using the Switch-and-Squash algorithm.
• Updates the large_ct column in the ciphertexts table for the corresponding handle.
• Emits an event indicating the availability of the computed large_ct.

Features

decrypt_128 - Decrypt each large_ct and print it as a plaintext (for testing purposes only).

Binary (sns-worker)

Runs sns-executor. See also src/bin/utils/daemon_cli.rs

Running a SnS Worker

The SnS key can be retrieved from the Large Objects table (pg_largeobject). Before running a worker, the sns_pk should be imported into the keys table as shown below.

-- Example query to import sns_pk from fhevm-keys/sns_pk
-- Import the sns_pk into the Large Object storage
sns_pk_loid := lo_import('../fhevm-keys/sns_pk');

-- Update the keys table with the new Large Object OID
UPDATE keys
SET sns_pk = sns_pk_loid
WHERE key_id = ...; -- specify the appropriate key_id

Multiple workers can be launched independently to perform 128-PBS computations.

# Run a single instance of the worker
DATABASE_URL=postgresql://postgres:postgres@localhost:5432/coprocessor \
cargo run --release -- \
--pg-listen-channels "event_pbs_computations" "event_ciphertext_computed" \
--pg-notify-channel "event_pbs_computed" \

Notes:

• host_chain_id is read directly from pbs_computations/ciphertext_digest rows.

Testing

• Using Postgres docker image

# Run Postgres as image, execute migrations and populate the DB instance with keys from fhevm-keys
cargo test --release -- --nocapture

• Using localhost DB

# Use COPROCESSOR_TEST_LOCALHOST_RESET to execute migrations once
COPROCESSOR_TEST_LOCALHOST_RESET=1  cargo test --release -- --nocapture

# Then, on every run
COPROCESSOR_TEST_LOCALHOST=1  cargo test --release