Parallel ARithMEticS on tfhe ENcrypted data
Parmesan implements selected parallel algorithms for multi-digit arithmetics over TFHE ciphertexts. Namely:
- addition/subtraction,
- scalar multiplication (i.e., multiplication by a known integer),
- multiplication,
- squaring,
- signum,
- maximum of two numbers, and
- evaluation of a simple neural network.
In the standard integer representation, parallel addition is not possible due to the carry, which can propagate all the way from the LSB to the MSB. However, using, e.g., an alphabet {-1,0,1}
for base-2 integer representation, a parallel addition algorithm does exist.
See our full paper.
Add a dependency to your Cargo.toml
file in your Rust project. (Currently only from git or locally.)
[dependencies]
parmesan = { git = "https://gitlab.fit.cvut.cz/klemsjak/parmesan" }
# or:
parmesan = { path = "../parmesan" }
For the best performance, we recommend to compile & run with the RUSTFLAGS="-C target-cpu=native" cargo run --release
command.
use std::error::Error;
use colored::Colorize;
use parmesan::params;
use parmesan::userovo::*;
use parmesan::ParmesanUserovo;
use parmesan::ParmesanCloudovo;
use parmesan::arithmetics::ParmArithmetics;
pub fn main() -> Result<(), Box<dyn Error>> {
// =================================
// Initialization
// ---------------------------------
// Global Scope
let par = ¶ms::PARM80__PI_5__D_20;
// ---------------------------------
// Userovo Scope
let pu = ParmesanUserovo::new(par)?;
let pub_k = pu.export_pub_keys();
// ---------------------------------
// Cloudovo Scope
let pc = ParmesanCloudovo::new(par, &pub_k);
// =================================
// U: Encryption
let a: Vec<i32> = vec![1,0,1,-1,-1,0,-1,1,1,-1,1,1,1,-1,-1,0,0,1,1,0,0,0,0,-1,0,0,0,0,0,-1,0,0,];
let b: Vec<i32> = vec![-1,0,0,-1,1,1,-1,1,-1,0,0,1,0,1,1,0,0,0,-1,0,0,1,0,0,-1,0,-1,-1,-1,1,1,0,];
let ca = pu.encrypt_vec(&a)?;
let cb = pu.encrypt_vec(&b)?;
// convert to actual numbers
let a_val = encryption::convert(&a)?;
let b_val = encryption::convert(&b)?;
// print plain inputs
println!("\nInputs:\n");
println!("a = {:12}", a_val);
println!("b = {:12}", b_val);
// =================================
// C: Evaluation
let c_add_a_b = ParmArithmetics::add(&pc, &ca, &cb);
// =================================
// U: Decryption
let add_a_b = pu.decrypt(&c_add_a_b)?;
let mut summary_text = format!("\nResults:\n");
summary_text = format!("{}\nAddition:", summary_text);
summary_text = format!("{}\na + b = {:12} :: {} (exp. {})", summary_text,
add_a_b,
if add_a_b == a_val + b_val {String::from("PASS").bold().green()} else {String::from("FAIL").bold().red()},
a_val + b_val
);
println!("{}", summary_text);
println!("\nDemo END\n");
Ok(())
}
Parmesan is licensed under AGPLv3.