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Serialization

This document explains how to serialize and deserialize ciphertexts and secret keys when working with TFHE-rs in Rust.

Concrete already has its serilization functions (e.g. tfhers_bridge.export_value, tfhers_bridge.import_value, tfhers_bridge.keygen_with_initial_keys, tfhers_bridge.serialize_input_secret_key). However, when implementing a TFHE-rs computation in Rust, we must use a compatible serialization.

Ciphertexts

We can deserialize FheUint8 (and similarly other types) using bincode

To serialize

Secret Key

We can deserialize LweSecretKey using bincode

To serialize

Serialization

This document explains how to serialize and deserialize ciphertexts and secret keys when working with TFHE-rs in Rust.

Ciphertexts

We can deserialize FheUint8 (and similarly other types) using bincode

To serialize

Secret Key

We can deserialize LweSecretKey using bincode

use tfhe::core_crypto::prelude::LweSecretKey;

/// ...

fn load_lwe_sk(path: &String) -> LweSecretKey<Vec<u64>> {
    let path_sk: &Path = Path::new(path);
    let serialized_lwe_key = fs::read(path_sk).unwrap();
    let mut serialized_data = Cursor::new(serialized_lwe_key);
    bincode::deserialize_from(&mut serialized_data).unwrap()
}

To serialize

fn save_lwe_sk(lwe_sk: LweSecretKey<Vec<u64>>, path: &String) {
    let mut serialized_lwe_key = Vec::new();
    bincode::serialize_into(&mut serialized_lwe_key, &lwe_sk).unwrap();
    let path_sk: &Path = Path::new(path);
    fs::write(path_sk, serialized_lwe_key).unwrap();
}

use tfhe::FheUint8;

/// ...

fn load_fheuint8(path: &String) -> FheUint8 {
    let path_fheuint: &Path = Path::new(path);
    let serialized_fheuint = fs::read(path_fheuint).unwrap();
    let mut serialized_data = Cursor::new(serialized_fheuint);
    bincode::deserialize_from(&mut serialized_data).unwrap()
}

fn save_fheuint8(fheuint: FheUint8, path: &String) {
    let mut serialized_ct = Vec::new();
    bincode::serialize_into(&mut serialized_ct, &fheuint).unwrap();
    let path_ct: &Path = Path::new(path);
    fs::write(path_ct, serialized_ct).unwrap();
}

use tfhe::core_crypto::prelude::LweSecretKey;

/// ...

fn load_lwe_sk(path: &String) -> LweSecretKey<Vec<u64>> {
    let path_sk: &Path = Path::new(path);
    let serialized_lwe_key = fs::read(path_sk).unwrap();
    let mut serialized_data = Cursor::new(serialized_lwe_key);
    bincode::deserialize_from(&mut serialized_data).unwrap()
}

fn save_lwe_sk(lwe_sk: LweSecretKey<Vec<u64>>, path: &String) {
    let mut serialized_lwe_key = Vec::new();
    bincode::serialize_into(&mut serialized_lwe_key, &lwe_sk).unwrap();
    let path_sk: &Path = Path::new(path);
    fs::write(path_sk, serialized_lwe_key).unwrap();
}