TextCrypt #

A modular Dart package for text obfuscation and compression using various encoding/decoding techniques. This package provides a clean, extensible architecture for chaining multiple text transformation codecs together.

Features #

• 🔧 Modular Architecture: Each codec implements a common TextCodec interface
• ⛓️ Chainable Codecs: Combine multiple codecs in pipelines (e.g., GZip → Base64 → Hex)
• 🛡️ Built-in Codecs: Base64, GZip compression, and Hexadecimal encoding
• ✅ Pure Dart: No external dependencies, works everywhere Dart runs
• 🧪 Well Tested: Comprehensive test coverage with edge cases
• 📚 Fully Documented: Complete API documentation with examples

Built-in Codecs #

Installation #

Add this package to your pubspec.yaml:

dependencies:
  textcrypt: <latest_version>

Then run:

dart pub get

Quick Start #

Individual Codecs #

import 'package:textcrypt/textcrypt.dart';

void main() {
  // Base64 encoding
  const base64 = Base64Codec();
  final encoded = base64.encode('Hello, World!');
  final decoded = base64.decode(encoded);
  print('Encoded: $encoded'); // SGVsbG8sIFdvcmxkIQ==
  print('Decoded: $decoded'); // Hello, World!

  // Hex encoding with uppercase
  const hex = HexCodec(uppercase: true);
  final hexEncoded = hex.encode('Hi!');
  print('Hex: $hexEncoded'); // 486921

  // GZip compression
  const gzip = GzipCodec(level: 9);
  final compressed = gzip.encode('Repeated text ' * 100);
  print('Compression ratio: ${compressed.length / (1500)}'); // Much smaller!
}

Codec Pipelines #

import 'package:textcrypt/textcrypt.dart';

void main() {
  // Create a pipeline: Compress → Base64 → Hex
  final pipeline = CodecPipeline([
    const GzipCodec(level: 9),
    const Base64Codec(),
    const HexCodec(uppercase: true),
  ]);

  const originalText = 'This will be compressed, base64 encoded, then hex encoded!';
  
  // Encode through the entire pipeline
  final result = pipeline.encode(originalText);
  print('Pipeline result: $result');

  // Decode back to original (automatically reverses the pipeline)
  final recovered = pipeline.decode(result);
  print('Recovered: $recovered');
  print('Match: ${recovered == originalText}'); // true
}

API Reference #

TextCodec Interface #

All codecs implement the TextCodec interface:

abstract class TextCodec {
  String encode(String input);
  String decode(String input);
  bool isValidInput(String input);
  String get name;
}

Base64Codec #

const codec = Base64Codec();
final encoded = codec.encode('Hello'); // SGVsbG8=
final decoded = codec.decode('SGVsbG8='); // Hello

GzipCodec #

const codec = GzipCodec(level: 6); // Compression level 0-9
final compressed = codec.encode('Long repetitive text...');
final decompressed = codec.decode(compressed);

HexCodec #

const codec = HexCodec(uppercase: true); // Optional uppercase
final hex = codec.encode('Hi!'); // 486921
final text = codec.decode('486921'); // Hi!

CodecPipeline #

final pipeline = CodecPipeline([codec1, codec2, codec3]);

// Pipeline operations
final extended = pipeline.addCodec(newCodec);
final reduced = pipeline.removeCodec(index);
print('Pipeline: ${pipeline.name}'); // Pipeline[Codec1 → Codec2 → Codec3]

Advanced Usage #

Custom Codec Implementation #

class ROT13Codec implements TextCodec {
  @override
  String get name => 'ROT13';

  @override
  String encode(String input) {
    return input.split('').map((char) {
      final code = char.codeUnitAt(0);
      if (code >= 65 && code <= 90) {
        return String.fromCharCode((code - 65 + 13) % 26 + 65);
      } else if (code >= 97 && code <= 122) {
        return String.fromCharCode((code - 97 + 13) % 26 + 97);
      }
      return char;
    }).join();
  }

  @override
  String decode(String input) => encode(input); // ROT13 is symmetric

  @override
  bool isValidInput(String input) => input.isNotEmpty;
}

// Use in pipeline
final pipeline = CodecPipeline([
  ROT13Codec(),
  const Base64Codec(),
]);

Error Handling #

try {
  const codec = Base64Codec();
  final result = codec.decode('Invalid@Input');
} on FormatException catch (e) {
  print('Decoding failed: $e');
} on ArgumentError catch (e) {
  print('Invalid argument: $e');
}

Real-world Examples #

Data Obfuscation for Logs

final logObfuscator = CodecPipeline([
  const Base64Codec(),
  const HexCodec(),
]);

final sensitiveData = 'user_id:12345, email:user@example.com';
final obfuscated = logObfuscator.encode(sensitiveData);
// Store obfuscated data, decode when needed

Configuration Compression

final configCompressor = CodecPipeline([
  const GzipCodec(level: 9),
  const Base64Codec(),
]);

final largeConfig = '{"key": "value", ...}'; // Large JSON config
final compressed = configCompressor.encode(largeConfig);
// Significantly smaller for storage/transmission

Testing #

Run the test suite:

dart test

The package includes comprehensive tests for:

• Individual codec functionality
• Pipeline operations
• Error handling
• Edge cases and validation
• Performance characteristics

Contributing #

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

Development Setup #

1. Clone the repository
2. Run dart pub get
3. Make your changes
4. Run dart test to ensure tests pass
5. Run dart analyze to check for issues
6. Submit a pull request

License #

This project is licensed under the MIT License - see the LICENSE file for details.

🙋‍♂️ Support #

• 📧 Issues: GitHub Issues
• 💬 Discussions: GitHub Discussions
• ⭐ Star this repo if you find it useful!

Example #

See the example/ directory for a complete usage example.

Changelog #

See CHANGELOG.md for a detailed list of changes.

Made with ❤️ for the Dart community