# ClawdNode Android Debugging Session - 2025-01-28

## Problem
ClawdNode Android app fails to connect to Clawdbot gateway - shows "failed to connect".

## Root Cause #1 (Fixed Earlier)
**Cryptographic algorithm mismatch**: Gateway uses Ed25519 signatures, Android app was using ECDSA P-256. Fixed by switching to Bouncy Castle Ed25519.

## Root Cause #2 (Fixed 2025-01-28)
**Signature payload format was WRONG!**

Android was signing:
```
$nonce:$signedAt
```

Gateway actually expects (from `gateway/device-auth.js`):
```
v2|deviceId|clientId|clientMode|role|scopes|signedAtMs|token|nonce
```

Example: `v2|abc123def|clawdbot-android|node|node||1706470000000|gateway-token|challenge-nonce`

## Solution Implemented (Commit a1e94f5)

### DeviceIdentity.kt
Updated `signChallenge()` to accept all required parameters and build correct payload:
```kotlin
fun signChallenge(
    nonce: String,
    clientId: String,
    clientMode: String,
    role: String,
    scopes: String = "",
    token: String = ""
): SignedChallenge {
    val signedAt = System.currentTimeMillis()
    val payload = listOf(
        "v2", deviceId, clientId, clientMode, role, scopes,
        signedAt.toString(), token, nonce
    ).joinToString("|")
    // ... sign payload with Ed25519
}
```

### GatewayClient.kt
Updated `handleConnectChallenge()` to pass all parameters:
```kotlin
signedChallenge = deviceIdentity.signChallenge(
    nonce = nonce,
    clientId = Protocol.CLIENT_ID,  // "clawdbot-android"
    clientMode = Protocol.MODE,      // "node"
    role = Protocol.ROLE,            // "node"
    scopes = "",
    token = token  // gateway token
)
```

## Gateway Protocol Details (from source code analysis)

### WebSocket Handshake Flow
1. Client connects to `ws://gateway:18789/ws`
2. Gateway sends: `{"type": "event", "event": "connect.challenge", "payload": {"nonce": "...", "ts": ...}}`
3. Client sends connect request with signed device info
4. Gateway verifies signature, responds with `hello-ok`

### Device Auth Payload (v2)
Built by `buildDeviceAuthPayload()` in `gateway/device-auth.js`:
```
v2|deviceId|clientId|clientMode|role|scopes|signedAtMs|token|nonce
```

### Key Functions
```javascript
// Building payload (gateway/device-auth.js)
buildDeviceAuthPayload(params) {
  const base = [
    "v2", params.deviceId, params.clientId, params.clientMode,
    params.role, params.scopes.join(","), String(params.signedAtMs),
    params.token ?? "", params.nonce ?? ""
  ];
  return base.join("|");
}

// Signing (infra/device-identity.js)
signDevicePayload(privateKeyPem, payload) {
  return crypto.sign(null, Buffer.from(payload, "utf8"), key).toString("base64url");
}
```

### Device Identity Format
- **Public key**: 32 bytes raw, base64url encoded
- **Device ID**: SHA-256 hash of raw public key bytes, hex encoded
- **Signature**: Ed25519 signature of UTF-8 payload bytes, base64url encoded

## Android Implementation Notes
- Using Bouncy Castle Ed25519 (Android Keystore only supports Ed25519 on API 33+)
- Keys stored in EncryptedSharedPreferences (AES-256)
- 32-byte seed for private key, generates public key

## Next Steps to Test
1. On Mac Mini: `cd ~/dev/clawdnode-android && git pull origin main`
2. Android Studio: Sync & rebuild
3. On phone: Clear ClawdNode app data (regenerates keys)
4. Test connection

## Git Repo
`git@zurich.inou.com:clawdnode-android.git`

## Network Details
- Gateway: ws://100.123.216.65:18789/ws (Tailscale WebSocket)
- Phone Tailscale IP: 100.102.141.81
- Gateway host: james

## Debugging Commands
```bash
# Watch gateway logs (check for signature verification errors)
journalctl -u clawdbot -f | grep -i "device\|signature\|connect"

# Or if running via pm2/direct:
tail -f ~/.clawdbot/logs/*.log
```