We take security seriously. If you discover a security vulnerability in SimpleX TUI, please report it responsibly.

1. Go to our Security Advisories
2. Click "Report a vulnerability"
3. Fill out the form with details

If GitHub reporting is not possible, create a private issue or contact via GitHub.

Please provide as much information as possible:

• Description of the vulnerability
• Steps to reproduce the issue
• Affected versions
• Potential impact assessment
• Suggested fix (if any)

• SimpleX TUI application code
• Build and deployment scripts
• Documentation that could lead to security issues
• Dependencies with known vulnerabilities
• Radio transport protocol implementation (v0.5.0+)

• SimpleX Chat CLI (report to simplex-chat)
• SimpleX protocol issues
• Reticulum Network Stack (report to Reticulum)
• Social engineering attacks
• Physical attacks
• Issues in user's environment

We support responsible security research. If you:

• Act in good faith
• Avoid privacy violations
• Avoid data destruction
• Do not exploit issues beyond verification
• Report promptly

We will:

• ✅ Not pursue legal action
• ✅ Work with you to understand the issue
• ✅ Credit you in the advisory (if desired)
• ✅ Keep you informed of our progress

# Keep SimpleX TUI updated
cd ~/simplex-tui
git pull
cargo build --release

# Keep SimpleX CLI updated
# Follow SimpleX Chat update instructions

• Run SimpleX CLI with minimal permissions
• Use Tor for enhanced privacy
• Keep your system and dependencies updated
• Review logs for suspicious activity

• Backup your SimpleX data directory regularly
• Use encrypted storage for sensitive data
• Secure your WebSocket connection (localhost only by default)

┌─────────────────┐     WebSocket      ┌─────────────────┐
│  SimpleX TUI    │◄──────────────────►│  SimpleX CLI    │
│  (This project) │     localhost      │  (Backend)      │
└─────────────────┘                    └─────────────────┘

1. No Encryption Handling: SimpleX TUI does NOT handle encryption. All cryptographic operations are performed by SimpleX Chat CLI.

2. Local WebSocket: By default, WebSocket runs on localhost only. Exposing it to a network is NOT recommended.

3. No Key Storage: SimpleX TUI does NOT store or access private keys.

4. Trust Model: Security depends on SimpleX Chat CLI. We are a frontend only.

The planned radio transport layer will implement its own cryptographic stack for off-grid communication. This section documents the security model.

• Direct implementation of cryptographic primitives in Rust
• Designed for isolated networks without mesh interoperability
• Full control over protocol behavior
• Audits and review welcome

• Uses Reticulum Network Stack encryption
• Curve25519 + AES-128 or ChaCha20
• Compatible with Nomad Network, Sideband, MeshChat
• Security depends on Reticulum implementation
• See: https://reticulum.network/manual/crypto.html

1. Direction Finding: Unlike Tor, radio transmissions can be located using direction-finding equipment. Users in sensitive situations should be aware of this limitation.

2. Signal Analysis: Even with encrypted content, transmission patterns (timing, frequency, duration) may reveal information about communication activity.

3. Physical Security: Radio hardware can be seized or tampered with. Consider physical security of your device.

4. Regulatory Compliance: Transmitting on certain frequencies may be illegal in your jurisdiction. Non-compliance could lead to legal consequences and confiscation of equipment.

5. Shared Spectrum: ISM bands are shared with other users. Interference is possible and your transmissions may be noticed.

┌─────────────────────────────────────────────────────────────────┐
│  Identity Key (Long-term)                                       │
│  ├── Generated once per installation                            │
│  ├── Ed25519 keypair                                            │
│  └── Used for signing and identity verification                 │
├─────────────────────────────────────────────────────────────────┤
│  Session Key (Ephemeral)                                        │
│  ├── Generated per conversation session                         │
│  ├── X25519 ECDH exchange                                       │
│  └── Provides forward secrecy                                   │
├─────────────────────────────────────────────────────────────────┤
│  Message Key (Per-message)                                      │
│  ├── Derived from session key via HKDF                          │
│  ├── Unique per message                                         │
│  └── ChaCha20-Poly1305 authenticated encryption                 │
└─────────────────────────────────────────────────────────────────┘

1. Use Tor as Primary: Radio should be a fallback, not primary transport. Tor provides better metadata protection.

2. Limit Transmission Time: Shorter transmissions are harder to locate.

3. Vary Location: If possible, don't always transmit from the same location.

4. Verify Contacts: Use out-of-band verification for contact identity keys.

5. Monitor Spectrum: Use RTL-SDR monitoring to be aware of your RF environment.

6. Secure Hardware: Keep your radio hardware physically secure.

1. No Custom Cryptography: We use well-established, audited cryptographic libraries.

2. Fail Secure: On any cryptographic error, the operation fails rather than falling back to insecure mode.

3. Constant Time: Cryptographic operations use constant-time implementations where available.

4. Secure Random: All random values are generated using cryptographically secure random number generators.

5. Memory Safety: Rust's memory safety guarantees help prevent common vulnerabilities.

We thank all security researchers who help improve SimpleX TUI.

No vulnerabilities reported yet. Be the first responsible disclosure!

• Security Issues: GitHub Private Vulnerability Reporting
• General Issues: GitHub Issues

Last updated: January 2026