Multi-Algorithm File Encryption & Decryption in Go

This project provides a robust implementation of file encryption and decryption using AES-GCM in Go.

Features

• AES (Advanced Encryption Standard) with GCM mode
• Secure key handling
• File-based encryption/decryption
• Command-line interface
• Makefile support

Requirements

• Go 1.21 or later

Supported Algorithm

AES (Advanced Encryption Standard)

• Key size: 16 bytes (AES-128)
• Modern, secure block cipher
• Uses GCM mode for authenticated encryption
• Recommended for secure data encryption

Usage

Setup

1. Clone the repository:

   git clone https://github.com/yourusername/go-encrypt
   cd go-encrypt/

Running the Program

1. Build the program:

   make build

2. Encrypt a file:

   make encrypt

3. Decrypt a file:

   make decrypt

Command Line Options

The program supports the following flags:

-key string    16-byte encryption/decryption key
-input string  input file path
-encrypt string output path for encrypted file
-decrypt string output path for decrypted file

Example Usage

1. Direct command line usage:

   ./go-encrypt -key "1234567890123456" -input "example.txt" -encrypt "encrypted.bin"
   ./go-encrypt -key "1234567890123456" -input "encrypted.bin" -decrypt "decrypted.txt"

2. Using Makefile (with default values):

   make encrypt  # Uses KEY=1234567890123456 and INPUT_FILE=example.csv
   make decrypt

Security Considerations

• Always use strong, random keys (16 bytes for AES-128)
• Keep your keys secure and never commit them to version control
• The implementation uses AES-GCM which provides both confidentiality and authenticity

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Testing

Running Tests

1. Run all tests:

   make test

2. Run tests with coverage:

   make test-coverage

   This will generate a coverage report in HTML format (coverage.html)

3. Run specific tests:

   go test -v ./... -run TestName

4. Run tests for a specific package:

   go test ./pkg/encryption -v

5. Run tests with race detection:

   go test -race ./...

Test Organization

Tests are organized in the following structure:

├── pkg/
│   ├── encryption/
│   │   ├── aes_test.go
│   │   ├── des_test.go
│   │   └── rc4_test.go
│   └── utils/
│       └── utils_test.go

Each test file corresponds to its implementation file and follows Go's standard testing conventions.

Test Coverage

The test suite includes:

• Unit tests for each encryption algorithm (AES, DES, RC4)
• Key size validation tests
• Encryption/decryption round-trip tests
• Error handling tests

Writing Tests

When contributing new features, please ensure:

• All new code is thoroughly tested
• Tests are placed in the appropriate _test.go file
• Test coverage is maintained or improved
• Tests are clear and well-documented