Add rust-aead-sample

Author: nojima

rust-aead-sample/Cargo.lock

@@ -0,0 +1,9 @@
+[package]
+name = "rust-aead-sample"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1.0.95"
+base64 = "0.22.1"
+chacha20poly1305 = "0.10.1"

rust-aead-sample/Cargo.toml

@@ -0,0 +1,49 @@
+use anyhow::anyhow;
+use base64::{prelude::BASE64_STANDARD_NO_PAD, Engine};
+use chacha20poly1305::{
+    aead::{Aead, AeadCore, KeyInit, OsRng, Payload},
+    ChaCha20Poly1305, Key, Nonce,
+};
+
+struct Encrypted {
+    nonce: Vec<u8>,
+    ciphertext: Vec<u8>,
+}
+
+fn encrypt(key: &[u8], plaintext: &[u8], aad: &[u8]) -> anyhow::Result<Encrypted> {
+    let cipher = ChaCha20Poly1305::new(Key::from_slice(key));
+    let nonce = ChaCha20Poly1305::generate_nonce(&mut OsRng);
+    let ciphertext = cipher
+        .encrypt(&nonce, Payload { msg: plaintext, aad })
+        .map_err(|_| anyhow!("failed to encrypt"))?;
+    Ok(Encrypted {
+        nonce: nonce.to_vec(),
+        ciphertext,
+    })
+}
+
+fn decrypt(key: &[u8], nonce: &[u8], ciphertext: &[u8], aad: &[u8]) -> anyhow::Result<Vec<u8>> {
+    let cipher = ChaCha20Poly1305::new(Key::from_slice(key));
+    let nonce = Nonce::from_slice(nonce);
+    let plaintext = cipher
+        .decrypt(nonce, Payload { msg: ciphertext, aad })
+        .map_err(|_| anyhow!("failed to decrypt"))?;
+    Ok(plaintext)
+}
+
+fn main() -> anyhow::Result<()> {
+    let key = ChaCha20Poly1305::generate_key(&mut OsRng);
+    let plaintext = b"Hello, World!!";
+    let aad = b"123";
+
+    let Encrypted { nonce, ciphertext } = encrypt(&key, plaintext, aad)?;
+
+    println!("nonce = {}", BASE64_STANDARD_NO_PAD.encode(&nonce));
+    println!("ciphertext = {}", BASE64_STANDARD_NO_PAD.encode(&ciphertext));
+
+    let decrypted = decrypt(&key, &nonce, &ciphertext, aad)?;
+
+    println!("decrypted = {}", String::from_utf8_lossy(&decrypted));
+
+    Ok(())
+}