Scaffold Rust workspace: warzone-protocol, server, client, mule

4 crates, all compile. 16/17 tests pass. warzone-protocol (core crypto): - Seed-based identity (Ed25519 + X25519 from 32-byte seed via HKDF) - BIP39 mnemonic encode/decode (24 words) - Fingerprint type (SHA-256 truncated, displayed as xxxx:xxxx:xxxx:xxxx) - ChaCha20-Poly1305 AEAD encrypt/decrypt with random nonce - HKDF-SHA256 key derivation - Pre-key bundle generation with Ed25519 signatures - X3DH key exchange (simplified, needs X25519 identity key in bundle) - Double Ratchet: full implementation with DH ratchet, chain ratchet, out-of-order message handling via skipped keys cache - Message format (WarzoneMessage envelope + RatchetHeader) - Session type with ratchet state - Storage trait definitions (PreKeyStore, SessionStore, MessageQueue) warzone-server (axum): - sled database (keys, messages, one-time pre-keys) - Routes: /v1/health, /v1/keys/register, /v1/keys/{fp}, /v1/messages/send, /v1/messages/poll/{fp}, /v1/messages/{id}/ack warzone-client (CLI): - `warzone init` — generate seed, show mnemonic, save to ~/.warzone/ - `warzone recover <words>` — restore from mnemonic - `warzone info` — show fingerprint and keys - Seed storage at ~/.warzone/identity.seed (600 perms) - Stubs for send, recv, chat commands warzone-mule: Phase 4 placeholder Known issue: X3DH test fails (initiate/respond use different DH ops due to missing X25519 identity key in bundle). Fix in next step. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-26 21:27:48 +04:00
parent 1e2a83402d
commit 651396fa13
5075 changed files with 36186 additions and 0 deletions
--- a/warzone/crates/warzone-protocol/src/ratchet.rs
+++ b/warzone/crates/warzone-protocol/src/ratchet.rs
@@ -0,0 +1,325 @@
+//! Double Ratchet algorithm implementation.
+//! Follows Signal's Double Ratchet specification.
+
+use std::collections::BTreeMap;
+
+use serde::{Deserialize, Serialize};
+use x25519_dalek::{PublicKey, StaticSecret};
+
+use crate::crypto::{aead_decrypt, aead_encrypt, hkdf_derive};
+use crate::errors::ProtocolError;
+
+const MAX_SKIP: u32 = 1000;
+
+/// A message produced by the ratchet.
+#[derive(Clone, Serialize, Deserialize)]
+pub struct RatchetMessage {
+    pub header: RatchetHeader,
+    pub ciphertext: Vec<u8>,
+}
+
+/// Header included with each ratchet message.
+#[derive(Clone, Serialize, Deserialize)]
+pub struct RatchetHeader {
+    /// Current DH ratchet public key.
+    pub dh_public: [u8; 32],
+    /// Number of messages in the previous sending chain.
+    pub prev_chain_length: u32,
+    /// Message number in the current sending chain.
+    pub message_number: u32,
+}
+
+/// The Double Ratchet state machine.
+#[derive(Serialize, Deserialize)]
+pub struct RatchetState {
+    dh_self: Vec<u8>, // StaticSecret bytes (32)
+    dh_remote: Option<[u8; 32]>,
+    root_key: [u8; 32],
+    chain_key_send: Option<[u8; 32]>,
+    chain_key_recv: Option<[u8; 32]>,
+    send_count: u32,
+    recv_count: u32,
+    prev_send_count: u32,
+    skipped: BTreeMap<([u8; 32], u32), [u8; 32]>, // (dh_pub, n) -> message_key
+}
+
+impl RatchetState {
+    /// Initialize as Alice (initiator). Alice knows Bob's ratchet public key.
+    pub fn init_alice(shared_secret: [u8; 32], bob_ratchet_pub: PublicKey) -> Self {
+        let dh_self = StaticSecret::random_from_rng(rand::rngs::OsRng);
+        let dh_out = dh_self.diffie_hellman(&bob_ratchet_pub);
+
+        let (root_key, chain_key_send) = kdf_rk(&shared_secret, dh_out.as_bytes());
+
+        RatchetState {
+            dh_self: dh_self.to_bytes().to_vec(),
+            dh_remote: Some(*bob_ratchet_pub.as_bytes()),
+            root_key,
+            chain_key_send: Some(chain_key_send),
+            chain_key_recv: None,
+            send_count: 0,
+            recv_count: 0,
+            prev_send_count: 0,
+            skipped: BTreeMap::new(),
+        }
+    }
+
+    /// Initialize as Bob (responder). Bob uses his signed pre-key as initial ratchet key.
+    pub fn init_bob(shared_secret: [u8; 32], our_ratchet_secret: StaticSecret) -> Self {
+        RatchetState {
+            dh_self: our_ratchet_secret.to_bytes().to_vec(),
+            dh_remote: None,
+            root_key: shared_secret,
+            chain_key_send: None,
+            chain_key_recv: None,
+            send_count: 0,
+            recv_count: 0,
+            prev_send_count: 0,
+            skipped: BTreeMap::new(),
+        }
+    }
+
+    /// Get our current DH ratchet public key.
+    fn dh_public(&self) -> PublicKey {
+        let mut bytes = [0u8; 32];
+        bytes.copy_from_slice(&self.dh_self);
+        let secret = StaticSecret::from(bytes);
+        PublicKey::from(&secret)
+    }
+
+    fn dh_secret(&self) -> StaticSecret {
+        let mut bytes = [0u8; 32];
+        bytes.copy_from_slice(&self.dh_self);
+        StaticSecret::from(bytes)
+    }
+
+    /// Encrypt a plaintext message.
+    pub fn encrypt(&mut self, plaintext: &[u8]) -> Result<RatchetMessage, ProtocolError> {
+        // If we don't have a sending chain yet (Bob's first message), do a DH ratchet step
+        if self.chain_key_send.is_none() {
+            if self.dh_remote.is_none() {
+                return Err(ProtocolError::RatchetError(
+                    "no remote DH key and no sending chain".into(),
+                ));
+            }
+            self.dh_ratchet_step()?;
+        }
+
+        let ck = self
+            .chain_key_send
+            .as_ref()
+            .ok_or_else(|| ProtocolError::RatchetError("no sending chain".into()))?;
+
+        let (new_ck, message_key) = kdf_ck(ck);
+        self.chain_key_send = Some(new_ck);
+
+        let header = RatchetHeader {
+            dh_public: *self.dh_public().as_bytes(),
+            prev_chain_length: self.prev_send_count,
+            message_number: self.send_count,
+        };
+
+        // AAD: serialized header
+        let aad = bincode::serialize(&header)
+            .map_err(|e| ProtocolError::SerializationError(e.to_string()))?;
+        let ciphertext = aead_encrypt(&message_key, plaintext, &aad);
+
+        self.send_count += 1;
+
+        Ok(RatchetMessage { header, ciphertext })
+    }
+
+    /// Decrypt a received ratchet message.
+    pub fn decrypt(&mut self, message: &RatchetMessage) -> Result<Vec<u8>, ProtocolError> {
+        // Check skipped messages first
+        let key = (message.header.dh_public, message.header.message_number);
+        if let Some(mk) = self.skipped.remove(&key) {
+            let aad = bincode::serialize(&message.header)
+                .map_err(|e| ProtocolError::SerializationError(e.to_string()))?;
+            return aead_decrypt(&mk, &message.ciphertext, &aad);
+        }
+
+        // If the message's DH key differs from what we have, perform DH ratchet
+        let need_ratchet = match self.dh_remote {
+            Some(ref remote) => *remote != message.header.dh_public,
+            None => true,
+        };
+
+        if need_ratchet {
+            // Skip any missed messages in the current receiving chain
+            if self.chain_key_recv.is_some() {
+                self.skip_messages(message.header.prev_chain_length)?;
+            }
+
+            // DH ratchet step
+            let their_pub = PublicKey::from(message.header.dh_public);
+
+            // New receiving chain
+            let dh_recv = self.dh_secret().diffie_hellman(&their_pub);
+            let (rk, ck_recv) = kdf_rk(&self.root_key, dh_recv.as_bytes());
+            self.root_key = rk;
+            self.chain_key_recv = Some(ck_recv);
+            self.recv_count = 0;
+
+            // New sending chain
+            self.prev_send_count = self.send_count;
+            self.send_count = 0;
+            let new_dh = StaticSecret::random_from_rng(rand::rngs::OsRng);
+            let dh_send = new_dh.diffie_hellman(&their_pub);
+            let (rk2, ck_send) = kdf_rk(&self.root_key, dh_send.as_bytes());
+            self.root_key = rk2;
+            self.chain_key_send = Some(ck_send);
+            self.dh_self = new_dh.to_bytes().to_vec();
+            self.dh_remote = Some(message.header.dh_public);
+        }
+
+        // Skip to the message number
+        self.skip_messages(message.header.message_number)?;
+
+        // Derive message key
+        let ck = self
+            .chain_key_recv
+            .as_ref()
+            .ok_or_else(|| ProtocolError::RatchetError("no receiving chain".into()))?;
+        let (new_ck, message_key) = kdf_ck(ck);
+        self.chain_key_recv = Some(new_ck);
+        self.recv_count += 1;
+
+        let aad = bincode::serialize(&message.header)
+            .map_err(|e| ProtocolError::SerializationError(e.to_string()))?;
+        aead_decrypt(&message_key, &message.ciphertext, &aad)
+    }
+
+    fn skip_messages(&mut self, until: u32) -> Result<(), ProtocolError> {
+        if self.recv_count + MAX_SKIP < until {
+            return Err(ProtocolError::MaxSkipExceeded);
+        }
+        if let Some(ref ck) = self.chain_key_recv.clone() {
+            let dh_pub = self.dh_remote.unwrap_or([0u8; 32]);
+            let mut current_ck = *ck;
+            while self.recv_count < until {
+                let (new_ck, mk) = kdf_ck(&current_ck);
+                self.skipped.insert((dh_pub, self.recv_count), mk);
+                current_ck = new_ck;
+                self.recv_count += 1;
+            }
+            self.chain_key_recv = Some(current_ck);
+        }
+        Ok(())
+    }
+
+    fn dh_ratchet_step(&mut self) -> Result<(), ProtocolError> {
+        let their_pub = self
+            .dh_remote
+            .map(PublicKey::from)
+            .ok_or_else(|| ProtocolError::RatchetError("no remote key for ratchet".into()))?;
+
+        self.prev_send_count = self.send_count;
+        self.send_count = 0;
+
+        let new_dh = StaticSecret::random_from_rng(rand::rngs::OsRng);
+        let dh_out = new_dh.diffie_hellman(&their_pub);
+        let (rk, ck_send) = kdf_rk(&self.root_key, dh_out.as_bytes());
+        self.root_key = rk;
+        self.chain_key_send = Some(ck_send);
+        self.dh_self = new_dh.to_bytes().to_vec();
+
+        Ok(())
+    }
+}
+
+/// Root key KDF: derive new root key + chain key from DH output.
+fn kdf_rk(root_key: &[u8; 32], dh_output: &[u8]) -> ([u8; 32], [u8; 32]) {
+    let derived = hkdf_derive(dh_output, root_key, b"warzone-ratchet-rk", 64);
+    let mut new_rk = [0u8; 32];
+    let mut chain_key = [0u8; 32];
+    new_rk.copy_from_slice(&derived[..32]);
+    chain_key.copy_from_slice(&derived[32..]);
+    (new_rk, chain_key)
+}
+
+/// Chain key KDF: derive new chain key + message key.
+fn kdf_ck(chain_key: &[u8; 32]) -> ([u8; 32], [u8; 32]) {
+    let mk_bytes = hkdf_derive(chain_key, b"", b"warzone-ratchet-mk", 32);
+    let ck_bytes = hkdf_derive(chain_key, b"", b"warzone-ratchet-ck", 32);
+    let mut new_ck = [0u8; 32];
+    let mut mk = [0u8; 32];
+    new_ck.copy_from_slice(&ck_bytes);
+    mk.copy_from_slice(&mk_bytes);
+    (new_ck, mk)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn make_pair() -> (RatchetState, RatchetState) {
+        let shared_secret = [42u8; 32];
+        let bob_ratchet = StaticSecret::random_from_rng(rand::rngs::OsRng);
+        let bob_ratchet_pub = PublicKey::from(&bob_ratchet);
+
+        let alice = RatchetState::init_alice(shared_secret, bob_ratchet_pub);
+        let bob = RatchetState::init_bob(shared_secret, bob_ratchet);
+        (alice, bob)
+    }
+
+    #[test]
+    fn basic_exchange() {
+        let (mut alice, mut bob) = make_pair();
+        let msg = alice.encrypt(b"hello bob").unwrap();
+        let plain = bob.decrypt(&msg).unwrap();
+        assert_eq!(plain, b"hello bob");
+    }
+
+    #[test]
+    fn bidirectional() {
+        let (mut alice, mut bob) = make_pair();
+
+        let m1 = alice.encrypt(b"hello bob").unwrap();
+        assert_eq!(bob.decrypt(&m1).unwrap(), b"hello bob");
+
+        let m2 = bob.encrypt(b"hello alice").unwrap();
+        assert_eq!(alice.decrypt(&m2).unwrap(), b"hello alice");
+
+        let m3 = alice.encrypt(b"how are you?").unwrap();
+        assert_eq!(bob.decrypt(&m3).unwrap(), b"how are you?");
+    }
+
+    #[test]
+    fn multiple_messages_same_direction() {
+        let (mut alice, mut bob) = make_pair();
+
+        let m1 = alice.encrypt(b"one").unwrap();
+        let m2 = alice.encrypt(b"two").unwrap();
+        let m3 = alice.encrypt(b"three").unwrap();
+
+        assert_eq!(bob.decrypt(&m1).unwrap(), b"one");
+        assert_eq!(bob.decrypt(&m2).unwrap(), b"two");
+        assert_eq!(bob.decrypt(&m3).unwrap(), b"three");
+    }
+
+    #[test]
+    fn out_of_order() {
+        let (mut alice, mut bob) = make_pair();
+
+        let m1 = alice.encrypt(b"one").unwrap();
+        let m2 = alice.encrypt(b"two").unwrap();
+        let m3 = alice.encrypt(b"three").unwrap();
+
+        // Deliver out of order
+        assert_eq!(bob.decrypt(&m3).unwrap(), b"three");
+        assert_eq!(bob.decrypt(&m1).unwrap(), b"one");
+        assert_eq!(bob.decrypt(&m2).unwrap(), b"two");
+    }
+
+    #[test]
+    fn many_messages() {
+        let (mut alice, mut bob) = make_pair();
+        for i in 0..100 {
+            let msg = format!("message {}", i);
+            let encrypted = alice.encrypt(msg.as_bytes()).unwrap();
+            let decrypted = bob.decrypt(&encrypted).unwrap();
+            assert_eq!(decrypted, msg.as_bytes());
+        }
+    }
+}