Add rust-ecdh-sample

Author: nojima

rust-ecdh-sample/Cargo.lock

@@ -0,0 +1,9 @@
+[package]
+name = "rust-ecdh-sample"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1.0.95"
+base64 = "0.22.1"
+x25519-dalek = { version = "2.0.1", features = ["getrandom", "static_secrets"] }

rust-ecdh-sample/Cargo.toml

@@ -0,0 +1,48 @@
+use base64::prelude::{BASE64_STANDARD_NO_PAD, Engine};
+use x25519_dalek::{PublicKey, SharedSecret, StaticSecret};
+
+struct State {
+    private_key: StaticSecret,
+    public_key: PublicKey,
+}
+
+fn generate_key() -> anyhow::Result<State> {
+    let private_key = StaticSecret::random();
+    let public_key = PublicKey::from(&private_key);
+    Ok(State {
+        private_key,
+        public_key,
+    })
+}
+
+fn key_exchange(state: &State, peer_public_key: &PublicKey) -> SharedSecret {
+    state.private_key.diffie_hellman(peer_public_key)
+}
+
+fn main() -> anyhow::Result<()> {
+    let alice = generate_key()?;
+    let bob = generate_key()?;
+
+    println!(
+        "alice/public_key = {}",
+        BASE64_STANDARD_NO_PAD.encode(alice.public_key.to_bytes())
+    );
+    println!(
+        "  bob/public_key = {}",
+        BASE64_STANDARD_NO_PAD.encode(bob.public_key.to_bytes())
+    );
+
+    let alice_secret = key_exchange(&alice, &bob.public_key);
+    let bob_secret = key_exchange(&bob, &alice.public_key);
+
+    println!(
+        "alice/shared_secret = {}",
+        BASE64_STANDARD_NO_PAD.encode(alice_secret.as_bytes())
+    );
+    println!(
+        "  bob/shared_secret = {}",
+        BASE64_STANDARD_NO_PAD.encode(bob_secret.as_bytes())
+    );
+
+    Ok(())
+}