pqc-binary-format 3.0.0

# Supported Cryptographic Algorithms

One section for each of the 51 algorithms in the registry (`Algorithm::ALL`, `src/algorithm.rs`), in identifier order; `tests/registry.rs` holds this document to it.

## Algorithm Categories

1. [Classical Algorithms](#classical-algorithms) (0x0050-0x00FF)
2. [Hybrid Algorithms](#hybrid-algorithms) (0x0100-0x01FF)
3. [Pure Post-Quantum Algorithms](#pure-post-quantum-algorithms) (0x0200-0x02FF)
4. [Max Secure Series](#max-secure-series) (0x0300-0x03FF)
5. [FN-DSA Series (Falcon-based)](#fn-dsa-series-falcon-based) (0x0400-0x04FF)
6. [Experimental Algorithms](#experimental-algorithms) (0x0500-0x05FF)
7. [HQC Code-Based Series](#hqc-code-based-series) (0x0600-0x06FF)
8. [NIST ML-KEM (FIPS 203)](#nist-ml-kem-fips-203) (0x0700-0x07FF)
9. [NIST ML-DSA (FIPS 204)](#nist-ml-dsa-fips-204) (0x0800-0x08FF)
10. [NIST SLH-DSA (FIPS 205)](#nist-slh-dsa-fips-205) (0x0900-0x09FF)

---

## Classical Algorithms

### 1. Classical (0x0050)

**Name:** Classical
**ID:** `0x0050`
**Security Level:** Classical Security (pre-quantum)

**Description:**
Traditional elliptic curve cryptography combined with AES symmetric encryption.

**Cryptographic Stack:**
- **Key Exchange:** X25519 (Curve25519 ECDH)
- **Signatures:** Ed25519
- **Symmetric Encryption:** AES-256-GCM
- **Key Size:** 32 bytes (X25519), 32 bytes (Ed25519)

**Use Cases:**
- Legacy system compatibility
- Performance-critical applications
- Non-quantum-threat environments

**Performance:**
- Key Generation: ~50 µs
- Encryption: ~5 MB/s
- Decryption: ~5 MB/s

**Quantum Resistant:** ❌ No

---

### 2. Password Classical (0x0051)

**Name:** Password Classical
**ID:** `0x0051`
**Security Level:** Classical Security

**Description:**
Password-based encryption using classical cryptography with key derivation.

**Cryptographic Stack:**
- **Key Derivation:** Argon2id
- **Symmetric Encryption:** AES-256-GCM
- **Salt:** 16 bytes random
- **Iterations:** 3 (moderate security)

**Use Cases:**
- Password-protected files
- User data encryption
- Backup encryption

**Performance:**
- Key Derivation: ~100 ms (intentionally slow)
- Encryption: ~50 MB/s
- Decryption: ~50 MB/s

**Quantum Resistant:** ❌ No

---

## Hybrid Algorithms

### 3. Hybrid (0x0100)

**Name:** Hybrid
**ID:** `0x0100`
**Security Level:** NIST Level 5 (256-bit classical + quantum-resistant)

**Description:**
Combines post-quantum and classical algorithms for maximum security during the quantum transition period.

**Cryptographic Stack:**
- **Post-Quantum KEM:** ML-KEM-1024 (Kyber1024)
- **Classical KEM:** X25519
- **Post-Quantum Signature:** ML-DSA-87 (Dilithium5)
- **Classical Signature:** Ed25519
- **Symmetric Encryption:** AES-256-GCM

**Key Sizes:**
- ML-KEM-1024 Public Key: 1,568 bytes
- ML-KEM-1024 Ciphertext: 1,568 bytes
- X25519 Key: 32 bytes
- ML-DSA-87 Public Key: 2,592 bytes
- ML-DSA-87 Signature: 4,595 bytes
- Ed25519 Key: 32 bytes

**Use Cases:**
- Enterprise security systems
- Government communications
- Long-term data protection
- NIST post-quantum transition

**Performance:**
- Key Generation: ~2 ms
- Encryption: ~1.5 MB/s
- Decryption: ~1.5 MB/s

**Quantum Resistant:** ✅ Yes (hybrid security)

**Advantages:**
- If PQC breaks, classical fallback remains secure
- If classical breaks, PQC remains secure
- NIST recommended approach

---

## Pure Post-Quantum Algorithms

### 4. Post-Quantum (0x0200)

**Name:** Post-Quantum
**ID:** `0x0200`
**Security Level:** NIST Level 5

**Description:**
Pure post-quantum cryptography using NIST-standardized algorithms.

**Cryptographic Stack:**
- **KEM:** ML-KEM-1024
- **Signature:** ML-DSA-87
- **Symmetric Encryption:** AES-256-GCM

**Use Cases:**
- Maximum quantum resistance
- Forward-looking security
- Research applications

**Performance:**
- Key Generation: ~1.5 ms
- Encryption: ~2 MB/s
- Decryption: ~2 MB/s

**Quantum Resistant:** ✅ Yes

---

### 5. Multi-Algorithm (0x0201)

**Name:** Multi-Algorithm
**ID:** `0x0201`
**Security Level:** Runtime selection

**Description:**
Runtime algorithm selection framework allowing dynamic algorithm choice based on context.

**Features:**
- Dynamic algorithm switching
- Context-aware selection
- Performance vs security trade-offs

**Use Cases:**
- Multi-tenant systems
- Adaptive security
- Algorithm research

**Quantum Resistant:** ✅ Depends on selected algorithm

---

### 6. ML-KEM-1024 (0x0202)

**Name:** ML-KEM-1024
**ID:** `0x0202`
**Security Level:** NIST Level 5

**Description:**
Pure ML-KEM-1024 (Module-Lattice-Based Key Encapsulation Mechanism) implementation.

**Cryptographic Stack:**
- **KEM:** ML-KEM-1024 (FIPS 203)
- **Symmetric Encryption:** AES-256-GCM

**Key Sizes:**
- Public Key: 1,568 bytes
- Private Key: 3,168 bytes
- Ciphertext: 1,568 bytes

**Use Cases:**
- NIST-compliant systems
- Quantum-resistant key exchange
- Standards-based deployment

**Performance:**
- Key Generation: ~800 µs
- Encapsulation: ~1 ms
- Decapsulation: ~1.2 ms

**Quantum Resistant:** ✅ Yes

---

### 7. Multi-KEM (0x0203)

**Name:** Multi-KEM Dual Layer
**ID:** `0x0203`
**Security Level:** NIST Level 5+

**Description:**
Two independent KEM layers for defense-in-depth.

**Cryptographic Stack:**
- **Layer 1:** ML-KEM-1024
- **Layer 2:** X25519
- **Symmetric Encryption:** AES-256-GCM

**Use Cases:**
- High-security applications
- Algorithmic diversity
- Fault tolerance

**Quantum Resistant:** ✅ Partial (one layer classical)

---

### 8. Multi-KEM Triple (0x0204)

**Name:** Multi-KEM Triple Layer
**ID:** `0x0204`
**Security Level:** NIST Level 5+

**Description:**
Three independent KEM layers with 2-of-3 threshold.

**Cryptographic Stack:**
- **Layer 1:** ML-KEM-1024
- **Layer 2:** X25519
- **Layer 3:** ML-KEM-768
- **Threshold:** 2 of 3 must succeed

**Use Cases:**
- Critical infrastructure
- Maximum security requirements
- Redundant key exchange

**Quantum Resistant:** ✅ Partial

---

### 9. Quad-Layer (0x0205)

**Name:** Quad-Layer Redundant
**ID:** `0x0205`
**Security Level:** NIST Level 5+

**Description:**
Four independent cryptographic layers with algorithmic diversity and 3-of-4 fault tolerance.

**Cryptographic Stack:**
- **Layer 1:** ML-KEM-1024 + ML-DSA-87 + AES-256-GCM
- **Layer 2:** X25519 + Ed25519 + ChaCha20-Poly1305
- **Layer 3:** ML-KEM-1024 + SPHINCS+ + AES-256-GCM
- **Layer 4:** BLAKE3 + SHA3-256 (Integrity layer)
- **Threshold:** 3 of 4 must succeed

**Use Cases:**
- 100+ year data archival
- National security
- Critical infrastructure
- Defense systems

**Performance:**
- Key Generation: ~8 ms
- Encryption: ~500 KB/s
- Decryption: ~500 KB/s

**Quantum Resistant:** ✅ Yes (3 of 4 layers)

**Advantages:**
- Breaking one algorithm doesn't compromise security
- Algorithmic diversity reduces attack surface
- Fault tolerance through redundancy

---

### 10. Lattice-Code Hybrid (0x0206)

**Name:** Lattice-Code Hybrid Stack
**ID:** `0x0206`
**Security Level:** NIST Level 4+

**Description:**
Combines lattice-based and code-based post-quantum cryptography.

**Cryptographic Stack:**
- **Lattice KEM:** ML-KEM-768
- **Code-based Signature:** Classic McEliece
- **Symmetric Encryption:** AES-256-GCM

**Use Cases:**
- Diversified PQC approach
- Research applications
- Standards comparison

**Quantum Resistant:** ✅ Yes

---

### 11. PQ3-Stack (0x0207)

**Name:** PQ3-Stack Forward Secrecy
**ID:** `0x0207`
**Security Level:** NIST Level 5

**Description:**
Post-quantum forward secrecy with continuous key ratcheting.

**Cryptographic Stack:**
- **Initial KEM:** ML-KEM-1024
- **Ratcheting:** X3DH-like protocol
- **Signature:** ML-DSA-87
- **Symmetric Encryption:** AES-256-GCM

**Features:**
- Forward secrecy
- Backward secrecy
- Session key rotation

**Use Cases:**
- Secure messaging
- Real-time communications
- Session-based protocols

**Quantum Resistant:** ✅ Yes

---

### 12. X25519MLKEM768 (0x0208)
**Name:** X25519MLKEM768 (X-Wing)
**ID:** `0x0208`
**Security Level:** NIST Level 3 (ML-KEM-768), with X25519 alongside

**Description:**
The X-Wing hybrid KEM (draft-connolly-cfrg-xwing-kem): ML-KEM-768 and X25519 combined so the shared secret holds while either holds. It is the pairing TLS 1.3 negotiates as X25519MLKEM768, so data sealed with it matches what browsers and servers already use on the wire.

**Cryptographic Stack:**
- **KEM:** ML-KEM-768 (FIPS 203) + X25519 (RFC 7748), X-Wing combiner (SHA3-256)
- **Symmetric Encryption:** AES-256-GCM

**Sizes:**
- Public Key: 1,216 bytes
- Private Key: 32 bytes (seed)
- Ciphertext: 1,120 bytes
- Shared Secret: 32 bytes

**Use Cases:**
- Matching the key exchange of TLS 1.3 hybrid deployments
- Migration: classical security stays while ML-KEM is new
- Small ciphertexts where Level 5 is not required

**Quantum Resistant:** ✅ Yes

---

### 13. FrodoKEM-1344 (0x0209)
**Name:** FrodoKEM-1344
**ID:** `0x0209`
**Security Level:** NIST Level 5

**Description:**
FrodoKEM over unstructured lattices (plain LWE): no ring or module structure for an attack to exploit, at the cost of large keys. ISO/IEC 18033-2 track; recommended by BSI and ANSSI as a conservative choice.

**Cryptographic Stack:**
- **KEM:** FrodoKEM-1344 (SHAKE)
- **Symmetric Encryption:** AES-256-GCM

**Sizes:**
- Public Key: 21,520 bytes
- Private Key: 43,088 bytes
- Ciphertext: 21,632 bytes
- Shared Secret: 32 bytes

**Use Cases:**
- Long-term confidentiality with the most conservative lattice assumption
- Cryptographic diversity beside ML-KEM
- Regulated deployments following BSI TR-02102-1

**Quantum Resistant:** ✅ Yes

---

### 14. Classic McEliece (0x020A)
**Name:** Classic-McEliece-6960119
**ID:** `0x020A`
**Security Level:** NIST Level 5

**Description:**
Classic McEliece, the code-based KEM with the longest record of cryptanalysis (since 1978), parameter set 6960119. Very large public keys, very small ciphertexts. ISO/IEC 18033-2.

**Cryptographic Stack:**
- **KEM:** Classic McEliece 6960119
- **Symmetric Encryption:** AES-256-GCM

**Sizes:**
- Public Key: 1,047,319 bytes
- Private Key: 13,948 bytes
- Ciphertext: 194 bytes
- Shared Secret: 32 bytes

**Use Cases:**
- Archival encryption where a public key is distributed once
- Diversity from lattices: security from decoding random linear codes
- Small ciphertexts per message

**Quantum Resistant:** ✅ Yes

---

### 15. FrodoKEM-976 (0x020B)
**Name:** FrodoKEM-976
**ID:** `0x020B`
**Security Level:** NIST Level 3

**Description:**
FrodoKEM over unstructured lattices at Level 3: the conservative LWE assumption with smaller keys than FrodoKEM-1344. Cited in BSI TR-02102-1.

**Cryptographic Stack:**
- **KEM:** FrodoKEM-976 (SHAKE)
- **Symmetric Encryption:** AES-256-GCM

**Sizes:**
- Public Key: 15,632 bytes
- Private Key: 31,296 bytes
- Ciphertext: 15,744 bytes
- Shared Secret: 24 bytes

**Use Cases:**
- Conservative lattice security at Level 3
- Diversity beside ML-KEM-768
- Regulated deployments following BSI TR-02102-1

**Quantum Resistant:** ✅ Yes

---

## Max Secure Series

High-security configurations optimized for specific use cases.

### 16. Max Secure: Lightweight (0x0300)

**Name:** Max Secure: PQ Lightweight
**ID:** `0x0300`
**Security Level:** NIST Level 3

**Description:**
Optimized for resource-constrained devices while maintaining quantum resistance.

**Cryptographic Stack:**
- **KEM:** ML-KEM-512 (smaller variant)
- **Signature:** ML-DSA-44
- **Symmetric Encryption:** AES-128-GCM

**Use Cases:**
- IoT devices
- Embedded systems
- Mobile applications

**Performance:**
- Key Generation: ~300 µs
- Encryption: ~5 MB/s
- Decryption: ~5 MB/s

**Quantum Resistant:** ✅ Yes

---

### 17. Max Secure: Pure PQ (0x0301)

**Name:** Max Secure: Pure PQ
**ID:** `0x0301`
**Security Level:** NIST Level 5

**Description:**
Maximum quantum resistance with pure post-quantum algorithms only.

**Cryptographic Stack:**
- **KEM:** ML-KEM-1024
- **Signature:** ML-DSA-87
- **Secondary Signature:** SLH-DSA-SHA2-256s
- **Symmetric Encryption:** AES-256-GCM

**Use Cases:**
- Maximum quantum threat protection
- Long-term secrets
- Government applications

**Quantum Resistant:** ✅ Yes (100% PQC)

---

### 18. Max Secure: Hybrid Transition (0x0302)

**Name:** Max Secure: Hybrid Transition
**ID:** `0x0302`
**Security Level:** NIST Level 5

**Description:**
Optimized for smooth transition from classical to post-quantum.

**Cryptographic Stack:**
- **PQ KEM:** ML-KEM-1024
- **Classical KEM:** X25519
- **PQ Signature:** ML-DSA-87
- **Classical Signature:** Ed25519
- **Symmetric:** AES-256-GCM

**Use Cases:**
- Enterprise migration
- Gradual rollout
- Backwards compatibility

**Quantum Resistant:** ✅ Yes (hybrid)

---

### 19. Max Secure: Stateless (0x0303)

**Name:** Max Secure: Stateless
**ID:** `0x0303`
**Security Level:** NIST Level 5

**Description:**
Stateless hash-based signatures for environments requiring no state management.

**Cryptographic Stack:**
- **KEM:** ML-KEM-1024
- **Signature:** SLH-DSA-SHA2-256s (stateless)
- **Symmetric Encryption:** AES-256-GCM

**Use Cases:**
- Distributed systems
- Blockchain applications
- Certificate authorities

**Quantum Resistant:** ✅ Yes

---

### 20. Max Secure: Crypto-Agile (0x0304)

**Name:** Max Secure: Crypto-Agile
**ID:** `0x0304`
**Security Level:** Variable

**Description:**
Dynamic algorithm selection with hot-swapping capabilities.

**Features:**
- Runtime algorithm switching
- Zero-downtime migration
- A/B testing support

**Use Cases:**
- Multi-year deployments
- Algorithm research
- Future-proofing

**Quantum Resistant:** ✅ Configurable

---

### 21. Max Secure: PQC + ZK (0x0305)

**Name:** Max Secure: PQC + Zero-Knowledge
**ID:** `0x0305`
**Security Level:** NIST Level 5

**Description:**
Combines post-quantum cryptography with zero-knowledge proofs for privacy-preserving authentication.

**Cryptographic Stack:**
- **KEM:** ML-KEM-1024
- **Signature:** ML-DSA-87
- **ZK Proofs:** PLONK/Groth16
- **Symmetric Encryption:** AES-256-GCM

**Use Cases:**
- Privacy-preserving systems
- Anonymous authentication
- Verifiable computation

**Quantum Resistant:** ✅ Yes

---

### 22. Max Secure: Hybrid Transition (0x0306)

**Name:** Max Secure: Hybrid Transition
**ID:** `0x0306`
**Security Level:** NIST Level 5

**Description:**
Enhanced hybrid configuration for enterprise transition scenarios.

**Cryptographic Stack:**
- **PQ KEM:** ML-KEM-1024
- **Classical KEM:** X25519
- **PQ Signature:** ML-DSA-87 + SPHINCS+
- **Classical Signature:** Ed25519
- **Symmetric:** AES-256-GCM

**Quantum Resistant:** ✅ Yes

---

## FN-DSA Series (Falcon-based)

Signature algorithms using Falcon (Fast Fourier Lattice-based Compact Signatures).

### 23. FN-DSA 512: Compact (0x0400)

**Name:** FN-DSA 512: Compact
**ID:** `0x0400`
**Security Level:** NIST Level 1

**Description:**
Compact signatures optimized for bandwidth-constrained environments.

**Cryptographic Stack:**
- **KEM:** ML-KEM-512
- **Signature:** Falcon-512
- **Symmetric Encryption:** AES-128-GCM

**Signature Size:** ~666 bytes (smallest PQC signature)

**Use Cases:**
- Satellite communications
- IoT certificates
- Low-bandwidth networks

**Quantum Resistant:** ✅ Yes

---

### 24. FN-DSA 1024: High-Security (0x0401)

**Name:** FN-DSA 1024: High-Security
**ID:** `0x0401`
**Security Level:** NIST Level 5

**Description:**
Maximum security Falcon-based signatures.

**Cryptographic Stack:**
- **KEM:** ML-KEM-1024
- **Signature:** Falcon-1024
- **Symmetric Encryption:** AES-256-GCM

**Signature Size:** ~1,280 bytes

**Use Cases:**
- High-security applications
- Government communications
- Critical signatures

**Quantum Resistant:** ✅ Yes

---

### 25. FN-DSA: Floating-Point Hardened (0x0402)

**Name:** FN-DSA: Floating-Point Hardened
**ID:** `0x0402`
**Security Level:** NIST Level 3

**Description:**
Falcon implementation with hardening against floating-point side-channels.

**Features:**
- Constant-time floating-point operations
- Side-channel resistance
- Deterministic rounding

**Use Cases:**
- Hardware security modules
- Side-channel resistant systems
- Embedded secure elements

**Quantum Resistant:** ✅ Yes

---

### 26. FN-DSA: Dual Signature (0x0403)

**Name:** FN-DSA: Dual Signature
**ID:** `0x0403`
**Security Level:** NIST Level 5

**Description:**
Two independent signature schemes for redundancy.

**Cryptographic Stack:**
- **Primary Signature:** Falcon-1024
- **Secondary Signature:** ML-DSA-87
- **KEM:** ML-KEM-1024

**Use Cases:**
- Critical signatures
- Non-repudiation
- Legal documents

**Quantum Resistant:** ✅ Yes

---

### 27. FN-DSA: Transition Stack (0x0404)

**Name:** FN-DSA: Transition Stack
**ID:** `0x0404`
**Security Level:** NIST Level 5

**Description:**
Falcon + classical signatures for transition period.

**Cryptographic Stack:**
- **PQ Signature:** Falcon-1024
- **Classical Signature:** Ed25519
- **KEM:** ML-KEM-1024 + X25519

**Quantum Resistant:** ✅ Hybrid

---

### 28. FN-DSA + ZK Stack (0x0405)

**Name:** FN-DSA + Zero-Knowledge Stack
**ID:** `0x0405`
**Security Level:** NIST Level 5

**Description:**
Falcon signatures with zero-knowledge proof integration.

**Features:**
- Privacy-preserving signatures
- Selective disclosure
- ZK-SNARK/STARK support

**Use Cases:**
- Anonymous credentials
- Privacy-preserving PKI
- Blockchain identity

**Quantum Resistant:** ✅ Yes

---

### 29. FN-DSA: ZK Stack Enhanced (0x0406)

**Name:** FN-DSA + ZK Stack Enhanced
**ID:** `0x0406`
**Security Level:** NIST Level 5

**Description:**
Enhanced zero-knowledge integration with advanced features.

**Features:**
- Recursive proofs
- Proof aggregation
- Batch verification

**Quantum Resistant:** ✅ Yes

---

### 30. FN-DSA: Transition Stack Enhanced (0x0407)

**Name:** FN-DSA: Transition Stack Enhanced
**ID:** `0x0407`
**Security Level:** NIST Level 5

**Description:**
Enhanced transition configuration with additional features.

**Cryptographic Stack:**
- **PQ Signature:** Falcon-1024
- **Classical Signature:** Ed25519 + ECDSA P-256
- **KEM:** ML-KEM-1024 + X25519

**Quantum Resistant:** ✅ Hybrid

---

## Experimental Algorithms

Research and next-generation algorithms. Use with caution in production.

### 31. Quantum-Inspired Lattice Fusion (0x0500)

**Name:** Quantum-Inspired Lattice Fusion
**ID:** `0x0500`
**Security Level:** Experimental

**Description:**
Novel lattice-based approach inspired by quantum computing principles.

**Features:**
- Quantum-inspired optimization
- Enhanced lattice structures
- Experimental cryptanalysis

**Status:** ⚠️ Experimental - Not for production use

**Quantum Resistant:** ⚠️ Unproven

---

### 32. Post-ZK Homomorphic (0x0501)

**Name:** Post-ZK Homomorphic Stack
**ID:** `0x0501`
**Security Level:** Experimental

**Description:**
Combines post-quantum cryptography with lightweight fully homomorphic encryption (LFHE 2023).

**Cryptographic Stack:**
- **KEM:** ML-KEM-1024
- **Signature:** ML-DSA-87
- **FHE:** LFHE 2023 (Boolean scheme)
- **ZK Proofs:** PLONK

**Key Innovation:**
- **Sub-MB FHE keys** (8-16 MB vs 400+ MB traditional FHE)
- Enables HTTP transmission of FHE keys
- Practical homomorphic encryption

**Use Cases:**
- Privacy-preserving computation
- Confidential smart contracts
- Encrypted machine learning
- Secure multi-party computation

**Status:** ⚠️ Experimental - LFHE 2023 is cutting-edge research

**Quantum Resistant:** ✅ Yes (but experimental)

---

### 33. Quantum-Resistant Consensus (0x0502)

**Name:** Quantum-Resistant Consensus
**ID:** `0x0502`
**Security Level:** Experimental

**Description:**
Post-quantum algorithms optimized for blockchain consensus.

**Features:**
- Fast verification
- Small signatures
- Consensus-optimized

**Use Cases:**
- Quantum-resistant blockchains
- Distributed systems
- Byzantine fault tolerance

**Status:** ⚠️ Experimental

**Quantum Resistant:** ✅ Yes

---

### 34. Entropy-Orchestrated PQ Stack (0x0503)

**Name:** Entropy-Orchestrated PQ Stack
**ID:** `0x0503`
**Security Level:** Experimental

**Description:**
Adaptive algorithm selection based on real-time entropy monitoring.

**Features:**
- Dynamic entropy assessment
- Adaptive security levels
- Entropy-driven key generation

**Status:** ⚠️ Experimental

**Quantum Resistant:** ✅ Yes

---

### 35. Lattice-Code Hybrid FN (0x0504)

**Name:** Lattice-Code Hybrid FN
**ID:** `0x0504`
**Security Level:** Experimental

**Description:**
Falcon-based hybrid with code-based backup.

**Status:** ⚠️ Experimental

**Quantum Resistant:** ✅ Yes

---

### 36. AI-Synthesized Crypto-Agile (0x0505)

**Name:** AI-Synthesized Crypto-Agile
**ID:** `0x0505`
**Security Level:** Experimental

**Description:**
Machine learning-assisted algorithm selection and optimization.

**Features:**
- AI-driven parameter tuning
- Context-aware algorithm selection
- Performance prediction

**Status:** ⚠️ Experimental

**Quantum Resistant:** ⚠️ Configurable

---

### 37. Experimental Engine (0x0506)

**Name:** Experimental Engine (Generic)
**ID:** `0x0506`
**Security Level:** Experimental

**Description:**
Generic experimental algorithm placeholder for research.

**Status:** ⚠️ Experimental

**Quantum Resistant:** ⚠️ Unknown

---

## HQC Code-Based Series

### 38. HQC-128 (0x0600)

**Name:** HQC-128
**ID:** `0x0600`
**Security Level:** NIST Level 1 (128-bit security)

**Description:**
Hamming Quasi-Cyclic (HQC) code-based key encapsulation mechanism. NIST 2025 Backup KEM standard providing cryptographic diversity through code-based mathematics.

**Cryptographic Stack:**
- **Key Exchange:** HQC-128 (code-based KEM)
- **Signatures:** Ed25519
- **Symmetric Encryption:** AES-256-GCM
- **Key Size:** 2249 bytes (public), 2289 bytes (private)
- **Ciphertext:** 4481 bytes

**Use Cases:**
- Cryptographic diversity (different math from lattice-based)
- Defense-in-depth with multiple PQ families
- NIST compliance requirements

**Performance:**
- Key Generation: ~10 ms
- Encapsulation: ~15 ms
- Decapsulation: ~20 ms

**Quantum Resistant:** ✅ Yes (code-based)

---

### 39. HQC-192 (0x0601)

**Name:** HQC-192
**ID:** `0x0601`
**Security Level:** NIST Level 3 (192-bit security)

**Description:**
Medium-security HQC variant with enhanced security parameters.

**Cryptographic Stack:**
- **Key Exchange:** HQC-192 (code-based KEM)
- **Signatures:** Ed25519
- **Symmetric Encryption:** AES-256-GCM
- **Key Size:** 4522 bytes (public), 4562 bytes (private)
- **Ciphertext:** 9026 bytes

**Quantum Resistant:** ✅ Yes (code-based)

---

### 40. HQC-256 (0x0602)

**Name:** HQC-256
**ID:** `0x0602`
**Security Level:** NIST Level 5 (256-bit security)

**Description:**
Maximum-security HQC variant for high-assurance applications.

**Cryptographic Stack:**
- **Key Exchange:** HQC-256 (code-based KEM)
- **Signatures:** Ed25519
- **Symmetric Encryption:** AES-256-GCM
- **Key Size:** 7245 bytes (public), 7285 bytes (private)
- **Ciphertext:** 14469 bytes

**Quantum Resistant:** ✅ Yes (code-based)

---

## NIST ML-KEM (FIPS 203)

### 41. ML-KEM-512 (0x0700)
**Name:** ML-KEM-512
**ID:** `0x0700`
**Security Level:** NIST Level 1

**Description:**
ML-KEM (FIPS 203) at its smallest parameter set.

**Cryptographic Stack:**
- **KEM:** ML-KEM-512 (FIPS 203)

**Sizes:**
- Encapsulation Key: 800 bytes
- Decapsulation Key: 1,632 bytes
- Ciphertext: 768 bytes
- Shared Secret: 32 bytes

**Use Cases:**
- Constrained devices
- Level 1 deployments

**Quantum Resistant:** ✅ Yes

---

### 42. ML-KEM-768 (0x0701)
**Name:** ML-KEM-768
**ID:** `0x0701`
**Security Level:** NIST Level 3

**Description:**
ML-KEM (FIPS 203) at the parameter set NIST recommends by default.

**Cryptographic Stack:**
- **KEM:** ML-KEM-768 (FIPS 203)

**Sizes:**
- Encapsulation Key: 1,184 bytes
- Decapsulation Key: 2,400 bytes
- Ciphertext: 1,088 bytes
- Shared Secret: 32 bytes

**Use Cases:**
- General-purpose key establishment
- The ML-KEM half of X25519MLKEM768

**Quantum Resistant:** ✅ Yes

---

## NIST ML-DSA (FIPS 204)

### 43. ML-DSA-44 (0x0800)
**Name:** ML-DSA-44
**ID:** `0x0800`
**Security Level:** NIST Level 2

**Description:**
ML-DSA (FIPS 204), module-lattice signatures, smallest parameter set.

**Cryptographic Stack:**
- **Signature:** ML-DSA-44 (FIPS 204)

**Sizes:**
- Public Key: 1,312 bytes
- Private Key: 2,560 bytes
- Signature: 2,420 bytes

**Use Cases:**
- High-volume signing
- Constrained verifiers

**Quantum Resistant:** ✅ Yes

---

### 44. ML-DSA-65 (0x0801)
**Name:** ML-DSA-65
**ID:** `0x0801`
**Security Level:** NIST Level 3

**Description:**
ML-DSA (FIPS 204) at Level 3.

**Cryptographic Stack:**
- **Signature:** ML-DSA-65 (FIPS 204)

**Sizes:**
- Public Key: 1,952 bytes
- Private Key: 4,032 bytes
- Signature: 3,309 bytes

**Use Cases:**
- General-purpose signatures
- Certificates and code signing

**Quantum Resistant:** ✅ Yes

---

### 45. ML-DSA-87 (0x0802)
**Name:** ML-DSA-87
**ID:** `0x0802`
**Security Level:** NIST Level 5

**Description:**
ML-DSA (FIPS 204) at Level 5; the CNSA 2.0 signature.

**Cryptographic Stack:**
- **Signature:** ML-DSA-87 (FIPS 204)

**Sizes:**
- Public Key: 2,592 bytes
- Private Key: 4,896 bytes
- Signature: 4,627 bytes

**Use Cases:**
- CNSA 2.0 systems
- Long-lived signatures

**Quantum Resistant:** ✅ Yes

---

## NIST SLH-DSA (FIPS 205)

### 46. SLH-DSA-SHA2-128s (0x0900)
**Name:** SLH-DSA-SHA2-128s
**ID:** `0x0900`
**Security Level:** NIST Level 1

**Description:**
SLH-DSA (FIPS 205), stateless hash-based signatures over SHA-2: security rests on the hash function alone. The small variant: shorter signatures, slower signing.

**Cryptographic Stack:**
- **Signature:** SLH-DSA-SHA2-128s (FIPS 205)

**Sizes:**
- Public Key: 32 bytes
- Private Key: 64 bytes
- Signature: 7,856 bytes

**Use Cases:**
- Signatures that must outlast any structured-lattice assumption
- Firmware and root-of-trust signing

**Quantum Resistant:** ✅ Yes

---

### 47. SLH-DSA-SHA2-128f (0x0901)
**Name:** SLH-DSA-SHA2-128f
**ID:** `0x0901`
**Security Level:** NIST Level 1

**Description:**
SLH-DSA (FIPS 205), stateless hash-based signatures over SHA-2: security rests on the hash function alone. The fast variant: faster signing, longer signatures.

**Cryptographic Stack:**
- **Signature:** SLH-DSA-SHA2-128f (FIPS 205)

**Sizes:**
- Public Key: 32 bytes
- Private Key: 64 bytes
- Signature: 17,088 bytes

**Use Cases:**
- Signatures that must outlast any structured-lattice assumption
- Firmware and root-of-trust signing

**Quantum Resistant:** ✅ Yes

---

### 48. SLH-DSA-SHA2-192s (0x0902)
**Name:** SLH-DSA-SHA2-192s
**ID:** `0x0902`
**Security Level:** NIST Level 3

**Description:**
SLH-DSA (FIPS 205), stateless hash-based signatures over SHA-2: security rests on the hash function alone. The small variant: shorter signatures, slower signing.

**Cryptographic Stack:**
- **Signature:** SLH-DSA-SHA2-192s (FIPS 205)

**Sizes:**
- Public Key: 48 bytes
- Private Key: 96 bytes
- Signature: 16,224 bytes

**Use Cases:**
- Signatures that must outlast any structured-lattice assumption
- Firmware and root-of-trust signing

**Quantum Resistant:** ✅ Yes

---

### 49. SLH-DSA-SHA2-192f (0x0903)
**Name:** SLH-DSA-SHA2-192f
**ID:** `0x0903`
**Security Level:** NIST Level 3

**Description:**
SLH-DSA (FIPS 205), stateless hash-based signatures over SHA-2: security rests on the hash function alone. The fast variant: faster signing, longer signatures.

**Cryptographic Stack:**
- **Signature:** SLH-DSA-SHA2-192f (FIPS 205)

**Sizes:**
- Public Key: 48 bytes
- Private Key: 96 bytes
- Signature: 35,664 bytes

**Use Cases:**
- Signatures that must outlast any structured-lattice assumption
- Firmware and root-of-trust signing

**Quantum Resistant:** ✅ Yes

---

### 50. SLH-DSA-SHA2-256s (0x0904)
**Name:** SLH-DSA-SHA2-256s
**ID:** `0x0904`
**Security Level:** NIST Level 5

**Description:**
SLH-DSA (FIPS 205), stateless hash-based signatures over SHA-2: security rests on the hash function alone. The small variant: shorter signatures, slower signing.

**Cryptographic Stack:**
- **Signature:** SLH-DSA-SHA2-256s (FIPS 205)

**Sizes:**
- Public Key: 64 bytes
- Private Key: 128 bytes
- Signature: 29,792 bytes

**Use Cases:**
- Signatures that must outlast any structured-lattice assumption
- Firmware and root-of-trust signing

**Quantum Resistant:** ✅ Yes

---

### 51. SLH-DSA-SHA2-256f (0x0905)
**Name:** SLH-DSA-SHA2-256f
**ID:** `0x0905`
**Security Level:** NIST Level 5

**Description:**
SLH-DSA (FIPS 205), stateless hash-based signatures over SHA-2: security rests on the hash function alone. The fast variant: faster signing, longer signatures.

**Cryptographic Stack:**
- **Signature:** SLH-DSA-SHA2-256f (FIPS 205)

**Sizes:**
- Public Key: 64 bytes
- Private Key: 128 bytes
- Signature: 49,856 bytes

**Use Cases:**
- Signatures that must outlast any structured-lattice assumption
- Firmware and root-of-trust signing

**Quantum Resistant:** ✅ Yes

---

## Algorithm Selection Guide

### By Use Case

| Use Case | Recommended Algorithm | ID |
|----------|----------------------|-----|
| **Legacy Compatibility** | Classical | 0x0050 |
| **Enterprise Transition** | Hybrid | 0x0100 |
| **Maximum Security** | Quad-Layer | 0x0205 |
| **IoT/Embedded** | Max Secure: Lightweight | 0x0300 |
| **Long-Term Archive** | Quad-Layer | 0x0205 |
| **Blockchain** | Quantum-Resistant Consensus | 0x0502 |
| **Privacy-Preserving** | Post-ZK Homomorphic | 0x0501 |
| **Standards Compliance** | Post-Quantum | 0x0200 |

### By Security Level

| NIST Level | Algorithms |
|------------|-----------|
| **Level 1** | FN-DSA 512 Compact |
| **Level 3** | Max Secure: Lightweight, FN-DSA FP Hardened |
| **Level 5** | Hybrid, Post-Quantum, ML-KEM-1024, Quad-Layer, Max Secure series |

### By Quantum Resistance

| Resistance | Algorithms |
|------------|-----------|
| **Not Resistant** | Classical, Password Classical |
| **Hybrid** | Hybrid, Multi-KEM, FN-DSA Transition |
| **Full PQC** | Post-Quantum, ML-KEM-1024, Quad-Layer, Max Secure: Pure PQ |

---

## Performance Comparison

| Algorithm | Key Gen | Encrypt | Decrypt | Sig Size | Quantum Safe |
|-----------|---------|---------|---------|----------|--------------|
| Classical | 50 µs | 5 MB/s | 5 MB/s | 64 B | ❌ |
| Hybrid | 2 ms | 1.5 MB/s | 1.5 MB/s | 4.6 KB | ✅ |
| Post-Quantum | 1.5 ms | 2 MB/s | 2 MB/s | 4.6 KB | ✅ |
| ML-KEM-1024 | 800 µs | 3 MB/s | 3 MB/s | - | ✅ |
| Quad-Layer | 8 ms | 500 KB/s | 500 KB/s | ~15 KB | ✅ |
| FN-DSA 512 | 1 ms | 3 MB/s | 3 MB/s | 666 B | ✅ |
| FN-DSA 1024 | 1.5 ms | 2 MB/s | 2 MB/s | 1.3 KB | ✅ |

---

## References

- [NIST Post-Quantum Cryptography](https://csrc.nist.gov/projects/post-quantum-cryptography)
- [ML-KEM (FIPS 203)](https://csrc.nist.gov/pubs/fips/203/final)
- [ML-DSA (FIPS 204)](https://csrc.nist.gov/pubs/fips/204/final)
- [SLH-DSA (FIPS 205)](https://csrc.nist.gov/pubs/fips/205/final)
- [Falcon Specification](https://falcon-sign.info/)
- [LFHE 2023 Research](https://eprint.iacr.org/2023/XXX)

---

**Last Updated:** January 9, 2026
**Format Version:** PQC Binary Format v1.0
**Total Algorithms:** 31 (includes 3 HQC code-based algorithms)