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As explained in the Introduction, most types are meant to be shared with the server that performs the computations.
The easiest way to send these data to a server is to use the serialization and deserialization features. tfhe uses the serde framework. Serde's Serialize and Deserialize functions are implemented on TFHE's types.
To serialize our data, a data format should be picked. Here, bincode is a good choice, mainly because it is a binary format.
# Cargo.toml
# ...
tfhe = { version = "0.4.1", features = ["integer","x86_64-unix"]}
bincode = "1.3.3"
use bincode;
use std::io::Cursor;
use tfhe::{ConfigBuilder, ServerKey, generate_keys, set_server_key, FheUint8};
use tfhe::prelude::*;
fn main() -> Result<(), Box<dyn std::error::Error>>{
let config = ConfigBuilder::all_disabled()
let ( client_key, server_key) = generate_keys(config);
let msg1 = 1;
let msg2 = 0;
let value_1 = FheUint8::encrypt(msg1, &client_key);
let value_2 = FheUint8::encrypt(msg2, &client_key);
// Prepare to send data to the server
// The ClientKey is _not_ sent
let mut serialized_data = Vec::new();
bincode::serialize_into(&mut serialized_data, &server_key)?;
bincode::serialize_into(&mut serialized_data, &value_1)?;
bincode::serialize_into(&mut serialized_data, &value_2)?;
// Simulate sending serialized data to a server and getting
// back the serialized result
let serialized_result = server_function(&serialized_data)?;
let result: FheUint8 = bincode::deserialize(&serialized_result)?;
let output: u8 = result.decrypt(&client_key);
assert_eq!(output, msg1 + msg2);
fn server_function(serialized_data: &[u8]) -> Result<Vec<u8>, Box<dyn std::error::Error>> {
let mut serialized_data = Cursor::new(serialized_data);
let server_key: ServerKey = bincode::deserialize_from(&mut serialized_data)?;
let ct_1: FheUint8 = bincode::deserialize_from(&mut serialized_data)?;
let ct_2: FheUint8 = bincode::deserialize_from(&mut serialized_data)?;
let result = ct_1 + ct_2;
let serialized_result = bincode::serialize(&result)?;