Add openssl-ecdh-sample

Author: nojima

openssl-ecdh-sample/Cargo.lock

@@ -0,0 +1,9 @@
+[package]
+name = "openssl-ecdh-sample"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1.0.95"
+base64 = "0.22.1"
+openssl = "0.10.70"

openssl-ecdh-sample/Cargo.toml

@@ -0,0 +1,56 @@
+use base64::{prelude::BASE64_STANDARD_NO_PAD, Engine};
+use openssl::{
+    derive::Deriver,
+    pkey::{Id, PKey, Private, Public},
+};
+
+struct State {
+    private_key: PKey<Private>,
+    public_key: PKey<Public>,
+}
+
+fn generate_key() -> anyhow::Result<State> {
+    let private_key = PKey::generate_x25519()?;
+    let public_key = {
+        let raw = private_key.raw_public_key()?;
+        PKey::public_key_from_raw_bytes(&raw, Id::X25519)?
+    };
+    Ok(State {
+        private_key,
+        public_key,
+    })
+}
+
+fn key_exchange(state: &State, peer_public_key: &PKey<Public>) -> anyhow::Result<Vec<u8>> {
+    let mut deriver = Deriver::new(&state.private_key)?;
+    deriver.set_peer(peer_public_key)?;
+    Ok(deriver.derive_to_vec()?)
+}
+
+fn main() -> anyhow::Result<()> {
+    let alice = generate_key()?;
+    let bob = generate_key()?;
+
+    println!(
+        "alice/public_key = {}",
+        BASE64_STANDARD_NO_PAD.encode(alice.public_key.public_key_to_der()?)
+    );
+    println!(
+        "  bob/public_key = {}",
+        BASE64_STANDARD_NO_PAD.encode(bob.public_key.public_key_to_der()?)
+    );
+
+    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)
+    );
+    println!(
+        "  bob/shared_secret = {}",
+        BASE64_STANDARD_NO_PAD.encode(bob_secret)
+    );
+
+    Ok(())
+}