Let's Decrypt - Comprehensive Usage Guide

Version 0.0.2 Update

Let's Decrypt is a powerful decryption tool supporting multiple encryption standards. Decrypt messages and files using various cryptographic algorithms with ease and efficiency. Let's Decrypt is a powerful decryption tool supporting multiple encryption standards. It allows users to decrypt messages and files using various cryptographic algorithms and efficiently manage decrypted outputs.

Added

  • New Encryption: Base64, Base32, Base16, RSA, Blowfish
  • Fixed AES-128, AES-192, AES-256, ChaCha20
    • The problem with AES was that it gave an Error that the Key was wrong (long or short)
    • ChaCha20 did not decrypt as it should have
  • Added Detect
  • Added Benchmark

Supported Encrypters

  • AES 128 (Advanced Encryption Standard with a 128-bit key)
  • AES 192 (Advanced Encryption Standard with a 192-bit key)
  • AES 256 (Advanced Encryption Standard with a 256-bit key)
  • Fernet (Symmetric encryption ensuring message integrity)
  • ChaCha20 (A high-performance stream cipher alternative to AES)
  • Base64 (Encoding scheme for binary-to-text data representation)
  • Base32 (Encoding scheme using a 32-character set for data representation)
  • Base16 (Hexadecimal encoding, also known as hex encoding)
  • RSA (Asymmetric encryption using public and private keys)
  • Blowfish (Symmetric-key block cipher known for speed and effectiveness)

1. Basic Decryption Syntax

letsdecrypt.py [OPTIONS] [INPUT]

The basic structure of Let's Decrypt involves specifying an encryption method, providing a key, and defining the input to decrypt.

2. Encryption Method Selection

Choose the appropriate encryption method based on your encrypted data:

# Fernet Decryption
letsdecrypt.py --fernet

# AES Decryption (multiple key lengths)
letsdecrypt.py --aes-128
letsdecrypt.py --aes-192
letsdecrypt.py --aes-256

# ChaCha20 Decryption
letsdecrypt.py --chacha20

# Base Encoding/Decoding
letsdecrypt.py --base64
letsdecrypt.py --base32
letsdecrypt.py --base16

# RSA Decryption
letsdecrypt.py --rsa

# Blowfish Decryption
letsdecrypt.py --blowfish

# Auto-Detect Encryption Method
letsdecrypt.py --detect

3. Key Input Methods

You can provide encryption keys in two primary ways:

# Direct Key Input
letsdecrypt.py --fernet --key "YOUR_ENCRYPTION_KEY"

# Key from File
letsdecrypt.py --aes-256 --key-file /path/to/key.txt

💡 Key Security Tips

  • Always use complex, unique keys
  • Store keys securely
  • Avoid hardcoding keys in scripts

4. Decryption Input Options

Decrypt messages or entire files with these options:

# Decrypt Direct Message
letsdecrypt.py --fernet --key SECRET_KEY --go-decrypt "ENCRYPTED_MESSAGE"

# Decrypt Entire File
letsdecrypt.py --aes-256 --key-file key.txt --go-decrypt-file encrypted_file.enc --iv-file iv.txt

5. Output Management

Control how decrypted content is handled:

# Save Decryption to Specific File
letsdecrypt.py --fernet --key SECRET_KEY \
    --go-decrypt "ENCRYPTED_MESSAGE" \
    --save-decrypt output.txt

# Generate Random Output Filename
letsdecrypt.py --aes-128 --key SECRET_KEY \
    --go-decrypt-file encrypted.bin \
    --save-decrypt-random \
    --iv IV

# Verbose Output Mode
letsdecrypt.py --fernet --key SECRET_KEY \
    --go-decrypt "MESSAGE" \
    --verbose

6. Complete Decryption Workflow Example

letsdecrypt.py \
    --aes-256 \
    --key-file /secure/keys/master_key.txt \
    --go-decrypt-file /data/sensitive_document.enc \
    --save-decrypt /output/decrypted_document.txt \
    --verbose

This example demonstrates a complete decryption process using AES-256, reading the key from a file, decrypting a specific file, and saving the output with verbose logging.

7. Benchmarking

Compare performance across different encryption methods:

# Run benchmark on all supported methods
letsdecrypt.py --benchmark 1  # MegaBytes

The benchmark feature helps determine the most efficient encryption method for your specific use case.

⚠️ Important Security Warnings

  • Protect your encryption keys at all times
  • Verify the source and integrity of encrypted files
  • Use strong, unique keys for each encryption
  • Be cautious when decrypting files from unknown sources

8. Troubleshooting Common Issues

  • Invalid Key: Double-check key format and encryption method
  • Decryption Failure: Verify correct encryption algorithm
  • Permission Errors: Ensure proper file access rights