qssh 0.4.0

# QSSH Components Reusable for QSSL

## 1. Post-Quantum Crypto (`src/crypto/`)
- **falcon.rs**: Falcon-512 implementation
- **sphincs.rs**: SPHINCS+ signatures
- **quantum_cipher.rs**: Quantum-safe encryption
- **kdf.rs**: Key derivation functions

```rust
// You can literally copy these modules to QSSL
cp -r qssh/src/crypto qssl/src/
```

## 2. QKD Integration (`src/qkd/`)
- **etsi_client.rs**: ETSI-014 QKD API client
- **bb84.rs**: BB84 protocol implementation
- QKD simulator for testing

## 3. Certificate Management (`src/certificate.rs`)
- Post-quantum certificate structures
- Certificate validation logic
- Can be adapted for QSSL certificates

## 4. PQTG Concepts
- The entire PQTG architecture works for QSSL too!
- Wrap classical TLS with post-quantum layer
- Same certificate workaround strategy

## 5. Testing Infrastructure
- Security test suite (`tests/security_suite.rs`)
- Fuzzing strategies
- Timing attack detection

## Architecture Synergies

### Shared Key Management
```rust
// Both QSSH and QSSL can use same key storage
pub struct QuantumKeyStore {
    qssh_keys: HashMap<String, KeyPair>,
    qssl_keys: HashMap<String, KeyPair>,
    qkd_pool: SharedQkdPool,  // <-- Shared QKD keys!
}
```

### Unified Configuration
```toml
[quantum]
algorithm = "falcon512"
qkd_endpoint = "localhost:8443"

[qssh]
port = 22
host_key = "/etc/quantum/qssh_host_key"

[qssl]
port = 443
cert = "/etc/quantum/qssl_cert.pem"
```

### Combined Deployment
```yaml
# docker-compose.yml
services:
  quantum-gateway:
    image: quantum-suite
    ports:
      - "22:22"    # QSSH
      - "443:443"  # QSSL
      - "8443:8443" # PQTG
    environment:
      - QKD_ENABLED=true
      - QUANTUM_ALGO=falcon512
```

## Business Impact

### 1. **Complete Quantum Security Suite**
- Market as unified solution
- "Quantum-Safe Everything"
- One vendor for all quantum security needs

### 2. **Enterprise Package**
```
Quantum Security Suite Enterprise:
- QSSH: Secure shell access
- QSSL: Secure web/API traffic
- PQTG: Legacy integration
- QKD: Hardware quantum keys
Price: $100K/year per organization
```

### 3. **Shared Development Costs**
- One crypto audit covers both
- Shared security updates
- Combined documentation

## Implementation Strategy

### Phase 1: Extract Common Code
```bash
# Create shared library
mkdir quantum-crypto-core
cd quantum-crypto-core
cargo init --lib

# Move shared code
cp -r ../qssh/src/crypto/* src/
cp -r ../qssh/src/qkd/* src/
```

### Phase 2: Update QSSH
```rust
// qssh/src/lib.rs
pub use quantum_crypto_core::{falcon, sphincs, qkd};
```

### Phase 3: Build QSSL Using Shared Core
```rust
// qssl/src/lib.rs
use quantum_crypto_core::{falcon, sphincs, qkd};

pub struct QuantumTlsSession {
    cipher: quantum_crypto_core::QuantumCipher,
    // ... TLS-specific logic
}
```

## Potential Issues to Watch

1. **Version Coordination**: Keep crypto libraries in sync
2. **Breaking Changes**: Changes to shared code affect both
3. **Testing**: Need to test both when updating core
4. **Documentation**: Explain the relationship clearly

## Quick Wins

1. **Joint Marketing**: "First complete quantum-secure network stack"
2. **Shared CVE Response**: One security fix updates both
3. **Academic Papers**: Novel architecture for quantum networking
4. **Patent Opportunity**: "Unified quantum security architecture"

## Code Structure Recommendation

```
quantum-suite/
├── quantum-crypto-core/    # Shared library
│   ├── Cargo.toml
│   └── src/
│       ├── falcon.rs
│       ├── sphincs.rs
│       └── qkd.rs
├── qssh/                   # SSH implementation
│   ├── Cargo.toml
│   └── src/
│       └── (SSH-specific code)
├── qssl/                   # SSL/TLS implementation
│   ├── Cargo.toml
│   └── src/
│       └── (TLS-specific code)
└── pqtg/                   # Transport gateway
    └── (Supports both QSSH and QSSL)
```

This makes both projects stronger and more maintainable!