research: TFHE demo.

script/research/tfhe/.gitignore

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+target/*
+Cargo.lock

script/research/tfhe/Cargo.toml

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+[package]
+name = "tfhe-experiments"
+version = "0.4.0"
+authors = ["Dyne.org foundation <foundation@dyne.org>"]
+license = "AGPL-3.0-only"
+edition = "2021"
+
+[workspace]
+
+[dependencies]
+tfhe = {version = "0.1.7", features = ["boolean", "shortint", "x86_64"]}

script/research/tfhe/src/main.rs

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+use tfhe::shortint::{gen_keys, Parameters};
+
+fn main() {
+    // Generate a set of client/server keys, using the default parameters.
+    // The client generates both keys. The server key is meant to be published
+    // so that homomorphic circuits can be computed.
+    let (client_key, server_key) = gen_keys(Parameters::default());
+
+    let msg1 = 3;
+    let msg2 = 2;
+
+    // Encrypt two messages using the (private) client key:
+    let ct_1 = client_key.encrypt(msg1);
+    let ct_2 = client_key.encrypt(msg2);
+
+    // Homomorphically compute an addition
+    let ct_add = server_key.unchecked_add(&ct_1, &ct_2);
+
+    // Define the Hamming weight function
+    // f: x -> sum of the bits of x
+    let f = |x: u64| x.count_ones() as u64;
+
+    // Generate the accumulator for the function
+    let acc = server_key.generate_accumulator(f);
+
+    // Compute the function over the ciphertext using the PBS
+    let ct_res = server_key.keyswitch_programmable_bootstrap(&ct_add, &acc);
+
+    // Decrypt the ciphertext using the (private) client key
+    let output = client_key.decrypt(&ct_res);
+    assert_eq!(output, f(msg1 + msg2));
+    println!("{:#b}", msg1 + msg2);
+}