From 9c33fca07428c47b4560607be53fb324e63ccad2 Mon Sep 17 00:00:00 2001
From: Hatter Jiang <jht5945@gmail.com>
Date: Sun, 10 Jan 2021 23:02:37 +0800
Subject: [PATCH] feat: crypto/ring

---
 __crypto/ring/src/main.rs | 99 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 94 insertions(+), 5 deletions(-)

diff --git a/__crypto/ring/src/main.rs b/__crypto/ring/src/main.rs
index f48f0bb..1aeeb01 100644
--- a/__crypto/ring/src/main.rs
+++ b/__crypto/ring/src/main.rs
@@ -1,8 +1,8 @@
-use ring::{
-    signature::{ KeyPair, Ed25519KeyPair, UnparsedPublicKey, ED25519 },
-    hmac, rand, error::Unspecified,
-    digest,
-};
+use std::num::NonZeroU32;
+
+use aead::{NONCE_LEN, Nonce, UnboundKey};
+use rand::SystemRandom;
+use ring::{aead::{self, LessSafeKey}, digest, error::Unspecified, hmac, pbkdf2, rand::SecureRandom, rand, signature::{ KeyPair, Ed25519KeyPair, UnparsedPublicKey, ED25519 }};
 
 const SEED_LEN: usize = 32;
 
@@ -37,6 +37,95 @@ fn main() -> Result<(), Unspecified> {
         let verify_result = UnparsedPublicKey::new(&ED25519, &public_key).verify(&"hello world".as_bytes(), sig.as_ref());
         println!("verify: {}", verify_result.is_ok());
     }
+    {
+        println!("{} Random  {}", "-".repeat(10), "-".repeat(10));
+        let mut random_bytes = [0_u8; 32];
+        let random = SystemRandom::new();
+        random.fill(&mut random_bytes).unwrap();
+        println!("Random bytes: {}", hex::encode(&random_bytes));
+    }
+    {
+        println!("{} Aead Crypto  {}", "-".repeat(10), "-".repeat(10));
+        let mut key = vec![];
+        for _ in 0..16 { key.push(0_u8); }
+        let aead_crypto = AeadCrypto::new(&key, &aead::AES_128_GCM);
+        let mut text = "hello world".as_bytes().to_vec();
+        println!("Cleartext: {}", hex::encode(&text));
+        aead_crypto.encrypt(&mut text);
+        println!("Encrypted: {}", hex::encode(&text));
+        let decrypt_result = aead_crypto.decrypt(&mut text);
+        println!("Decrypted: {}, text: {}", decrypt_result, hex::encode(text));
+    }
 
     Ok(())
 }
+
+pub trait Crypto: Send + Sync {
+    fn encrypt(&self, buf: &mut Vec<u8>);
+    fn decrypt(&self, buf: &mut Vec<u8>) -> bool;
+}
+
+pub struct AeadCrypto {
+    key: LessSafeKey,
+    algorithm: &'static aead::Algorithm,
+    random: SystemRandom,
+}
+
+impl AeadCrypto {
+    pub fn new(key: &[u8], algorithm: &'static aead::Algorithm) -> Self {
+        let salt = b"ap-kcp-aead-salt";
+        let mut key_bytes = Vec::with_capacity(algorithm.key_len());
+        key_bytes.resize(algorithm.key_len(), 0);
+        pbkdf2::derive(
+            pbkdf2::PBKDF2_HMAC_SHA256,
+            NonZeroU32::new(32).unwrap(),
+            salt,
+            key,
+            &mut key_bytes,
+        );
+        let key = UnboundKey::new(algorithm, &key_bytes).unwrap();
+        let key = LessSafeKey::new(key);
+        Self {
+            key,
+            algorithm,
+            random: SystemRandom::new(),
+        }
+    }
+}
+
+impl Crypto for AeadCrypto {
+    fn encrypt(&self, buf: &mut Vec<u8>) {
+        let mut nonce_bytes = [0u8; NONCE_LEN];
+        self.random.fill(&mut nonce_bytes).unwrap();
+        let nonce = Nonce::assume_unique_for_key(nonce_bytes);
+
+        // | ENCRPYTED | TAG | NONCE |
+        self.key
+            .seal_in_place_append_tag(nonce, aead::Aad::empty(), buf)
+            .unwrap();
+
+        buf.extend_from_slice(&nonce_bytes);
+    }
+
+    fn decrypt(&self, buf: &mut Vec<u8>) -> bool {
+        if buf.len() < aead::NONCE_LEN + self.algorithm.tag_len() {
+            return false;
+        }
+
+        let len = buf.len();
+        let mut nonce_bytes = [0u8; aead::NONCE_LEN];
+        nonce_bytes.copy_from_slice(&buf[len - aead::NONCE_LEN..]);
+        let nonce = Nonce::assume_unique_for_key(nonce_bytes);
+
+        buf.truncate(len - aead::NONCE_LEN);
+
+        let len = if let Ok(plaintext) = self.key.open_in_place(nonce, aead::Aad::empty(), buf) {
+            plaintext.len()
+        } else {
+            println!("[ERROR] failed to decrypt");
+            return false;
+        };
+        buf.truncate(len);
+        true
+    }
+}