5 releases (breaking)
| new 0.6.0 | Mar 15, 2026 |
|---|---|
| 0.5.0 | Mar 11, 2026 |
| 0.4.0 | Mar 11, 2026 |
| 0.2.0 | Mar 11, 2026 |
| 0.1.0 | Mar 11, 2026 |
#695 in Cryptography
22KB
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Lambda-Shield
A hardened, lightweight stream cipher built on chaotic Collatz trajectories + SipHash-1-2 mixing.
Lambda-Shield v0.5.0 introduces the Algebraic Wall—a defense-in-depth architecture that protects the internal state even in scenarios where primary keys are partially compromised. Designed for resource-constrained environments: IoT sensors, embedded MCUs, and edge devices.
cargo install lambda-shield
lambda-shield --msg 12345 67890 "Bazinga! Lemma 3 is live."
How It Works
Lambda-Shield uses a dual-layer architecture to decouple state evolution from output statistics.
- The Chaotic Driver (Collatz): Instead of a predictable counter ($n+1$), we use a hardened Collatz trajectory. This ensures that the difference ($\Delta$) between consecutive inputs to the mixer is non-linear and massive.
- The Cryptographic Mixer (SipHash): Two rounds of SipHash-1-2 provide full avalanche effects. Even a 1-bit change in the chaotic state results in ~50% bit-flip in the output keystream.
Security Advantage: The Algebraic Wall
Most modern stream ciphers (like ChaCha20) rely on a linear counter. While efficient, this creates a Single Point of Failure: if the key is leaked via a side-channel, the entire stream is compromised because the state ($n+1$) is trivial to predict.
Lambda-Shield provides State Recovery Resilience. In simulated attacks:
- Counter-based ciphers: Collapse instantly (100% prediction accuracy) upon key leak.
- Lambda-Shield: Accuracy remains 0%. An attacker must not only steal the key but also solve the non-linear trajectory position.
| Attack Scenario | Counter + SipHash | Lambda-Shield (Collatz) |
|---|---|---|
| Known Key, Unknown State | ❌ Compromised (100%) | ✅ Secure (0% Prediction) |
| Differential Predictability | Linear ($\Delta=1$) | Chaotic (Non-linear) |
| Algebraic Immunity | Low | High |
NIST SP 800-22 Results
Tested using the official NIST STS v2.1.2 on 1MB keystream (Seed: 12345 / 67890):
| Test Category | Passed | Result |
|---|---|---|
| Frequency / Runs / Rank | 1/1 | ✅ |
| Non-Overlapping Template | 148/148 | ✅ |
| Overlapping Template | 1/1 | ✅ |
| Linear Complexity | 1/1 | ✅ |
| TOTAL | 162/162 | ✅ ALL PASS |
Performance & Trade-offs
| Cipher | 10M Iterations (Speed) | Security Philosophy |
|---|---|---|
| Counter-based | ~11.5 ms | Efficiency First |
| Lambda-Shield | ~42.3 ms | Defense in Depth |
Real Security Overhead: ~268% slower than a raw counter. This "Security Tax" is intentional. By breaking CPU branch prediction through chaotic branching, Lambda-Shield ensures the state transition is as complex as the encryption itself.
Usage
Encrypt a message
lambda-shield --msg <seed_hi> <seed_lo> "your message"
Encrypt a file
lambda-shield --file <seed_hi> <seed_lo> path/to/file
Research & Verification
The research/ directory contains tools used to verify the "Algebraic Wall":
state_recovery_attack.rs: Simulates key-leak scenarios.checker.rs: Analyzes bit transition density.
⚠️ Security Notes
- Experimental: This is a research prototype. It has passed statistical batteries (NIST), but has not undergone formal community cryptanalysis.
- Nonce Misuse: Never reuse the same (seed_hi, seed_lo) pair for different messages.
- Intended Use: High-entropy state requirements, IoT security research, and hardware-compromise-resistant environments.
*Built with ❤️ by Abhishek Srivastava