logcrypt 1.1.0
Secure Python logging with RC4 encryption
License: Apache License 2.0

**Secure • Fast • Traceable** 
A modern, high-performance Python logging library with **optional strong encryption** (RC4 or AES-256-CBC), structured JSON output, correlation IDs, redaction, async support, and tamper detection.

Perfect for applications handling sensitive data — from fintech to healthcare.

---

## Key Features

| Feature                        | Description |
|-------------------------------|-----------|
| **Dual Encryption Modes**     | Choose between **RC4** (default, ultra-fast) or **AES-256-CBC** (maximum security) |
| **Automatic Algorithm Detection** | `decrypt_log()` tries both if you're unsure |
| **Tamper-Proof Logs**         | Every line includes SHA-256 checksum — corrupted/modified lines are skipped |
| **Custom Levels**             | `SUCCESS` (25) and `FAIL` (45) with `.success()` / `.fail()` methods |
| **Colored Console**           | Beautiful ANSI colors for instant visual feedback |
| **Correlation IDs**           | End-to-end request tracing with UUID or custom ID |
| **JSON Logging**              | Structured logs ready for ELK, Splunk, Datadog, etc. |
| **Async File Writing**        | Non-blocking via `QueueHandler` — zero performance impact |
| **PII Redaction**             | Automatically redact emails, IPs, tokens, credit cards via regex |
| **Smart Key Management**     | Load from file, validate, or auto-generate secure keys |
| **Zero-Config Native Speed**  | Falls back to pure Python if native extensions unavailable |

---

## Installation

```bash
pip install logcrypt
```

> Dependencies: `colorama`, `pycryptodome`

---

## Quick Start

### Basic Logging
```python
from logcrypt import Logger

logger = Logger(file_name="app.log", correlation_id="req-123")
logger.info("User logged in")
logger.success("Payment confirmed")
logger.close()
```

### Encrypted Logging (RC4 – default & fastest)
```python
logger = Logger(
    file_name="secure.log",
    encrypt_file=True,
    key_file="secret.key"  
)
logger.error("Login failed for user 42")
```

### Maximum Security (AES-256-CBC)
```python
logger = Logger(
    file_name="ultra_secure.log",
    encrypt_file=True,
    cipher_type="aes", 
    key_file="secret.key",
    # Can be any length — internally derived to 256-bit
)
logger.critical("PCI data accessed")
```

### JSON + Async + Redaction + AES
```python
logger = Logger(
    file_name="events.json.log",
    file_format="json",
    encrypt_file=True,
    cipher_type="aes",
    async_logging=True,
    redact_patterns=[
        r"\b\d{16}\b",                            # Credit cards
        r"\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b",  # Emails
    ]
)

logger.info("User john.doe@example.com paid with 4111111111111111")
# → REDACTED + encrypted safely
```

---

## Decrypting Logs

```python
from logcrypt import decrypt_log

# Auto-detects RC4 or AES
entries = decrypt_log("secure.log", key_from_file)

for entry in entries:
    print(f"[{entry['line_number']}] {entry['decrypted_line']}")

# Or force algorithm (rarely needed)
entries = decrypt_log("old.log", key, cipher_type="rc4")
```

Even if you forget the cipher type — it will try both and recover valid lines automatically.

---

## Console Output Example

```
This is an info message          (white)
Operation completed successfully (green)
Validation failed                (red)
Database connection lost         (bright red)
```

## File Output (encrypted example)
```
a3f1c9...e4d2:UElDUk9T... (checksum:encrypted_payload)
```

Only readable with the correct key.

---

## Security Notes

- Keys are **base64-encoded** and can be any length (AES derives proper 256-bit key via SHA-256)
- Always protect your key file:
  ```bash
  chmod 600 secret.key
  ```
- Never commit keys to version control
- Checksums prevent log tampering and injection attacks

---

## Package Structure

```
logcrypt/
├── __init__.py
├── core.py
├── cryptography.py  
├── cryptography.pyd      # Windows optimized RC4 + AES implementation
├── cryptography.so       # Linux optimized RC4 + AES implementation
├── key_manager.py
├── filters.py
├── formatters.py
├── decrypt_log.py
└── levels.py
```

## Performance Optimization

To improve encryption and decryption speed, **logcrypt** includes precompiled native extensions:

* **`cryptography.pyd`** – Windows  
* **`cryptography.so`** – Linux  

These modules automatically replace the pure Python `cryptography.py` implementation when available, delivering **faster RC4/AES operations** with lower CPU usage — especially beneficial in high-volume or multithreaded logging scenarios.

No configuration needed. The package detects your platform and loads the optimized version seamlessly.

> These extensions are compiled directly from the open `cryptography.py` source for transparency and trust.

---

## Notes & Security

- **Key Security**: Protect your key file:  
  ```bash
  chmod 600 secret.key
  ```
  Anyone with the key can decrypt logs.
- **Tamper Protection**: SHA-256 checksum ensures only valid entries are decrypted.

---

## License

MIT License

---

## Dependencies

- Python ≥ 3.8
- `colorama >= 0.1.1`
- `pycryptodome >= 3.0.0`

---

**LogCrypt** — Secure. Fast. Traceable.  
Built for developers who care about privacy and performance.