Cross-Language String Encryption Utility

This repository contains implementations of a simple string encryption and decryption utility across various programming languages. The goal is to provide interoperable encryption, allowing a string encrypted in one language to be decrypted in another, using a consistent scheme.

Encryption Scheme

The encryption scheme employed is as follows:

1. Salt Generation: A 16-byte random salt is generated.
2. Hex Encoding Salt: The 16 random salt bytes are hex-encoded to produce a 32-character string (salt_hex).
3. Combine Salt and Plaintext: The salt_hex string is prepended to the original plaintext string: combined_string = salt_hex + original_plaintext.
4. UTF-8 Encode: The combined_string is converted to a byte array using UTF-8 encoding: combined_bytes = combined_string.getBytes("UTF-8").
5. XOR Encryption: The combined_bytes are XORed byte-by-byte with a static key: "test_key". The key (also UTF-8 encoded) is repeated cyclically if shorter than the data.
6. Base64 Encoding: The resulting XORed byte array is Base64 encoded to produce the final encrypted string.

Decryption reverses this process:

1. Base64 Decode the encrypted string to get XORed bytes.
2. XOR Decrypt these bytes with the static key (UTF-8 encoded) to get decrypted_combined_bytes.
3. Convert decrypted_combined_bytes back to a string using UTF-8 encoding: decrypted_combined_string.
4. Extract the first 32 characters from decrypted_combined_string as the retrieved_salt_hex.
5. The remainder of decrypted_combined_string is the original plaintext.

Implemented Languages

Below is a list of implemented languages, their respective files, and basic instructions for running them. All implementations aim to provide a processString('e', "plaintext") function for encryption and processString('d', "encrypted_text") for decryption, or an equivalent.

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1. PHP

• File: StringEncryption.php
• Usage: Contains a StringEncryption class with a processString($type, $data) method.
• To Run: Include the file and call the methods. Requires a PHP environment.

  // <?php
  // require_once 'StringEncryption.php';
  // $crypter = new StringEncryption();
  // $encrypted = $crypter->processString('e', "Hello PHP");
  // echo "Encrypted: " . $encrypted . "\n";
  // $decrypted = $crypter->processString('d', $encrypted);
  // echo "Decrypted: " . $decrypted . "\n";
  // ?>

2. Java

• File: StringCrypter.java
• Usage: Contains a StringCrypter class with a static processString(char type, String data) method and a main method for tests.
• To Run:

  javac StringCrypter.java
  java StringCrypter

3. Python

• File: string_crypter.py
• Usage: Contains a StringCrypter class and a process_string(type_char, data_string) function, with example usage in if __name__ == "__main__":.
• To Run:

  python string_crypter.py

4. C# (.NET)

• File: StringCrypter.cs
• Usage: Contains a StringCrypter class with ProcessString(char type, string data) and a Main method for tests.
• To Run: Requires .NET SDK.

  # Assuming StringCrypter.cs is in a project or compiled directly
  # dotnet run (if part of a project)
  # or
  csc StringCrypter.cs
  StringCrypter.exe

  (Note: Compilation and execution were not fully tested due to potential environment constraints during development.)

5. C++

• Files:
  • StringCrypter.h (Header-only library)
  • TestStringCrypter.cpp (Example usage)
• Usage: Include StringCrypter.h and use the StringCrypter::processString(char type, const std::string& data) function.
• To Compile & Run Example (e.g., with g++):

  g++ TestStringCrypter.cpp -o test_cpp -std=c++11
  ./test_cpp

6. C

• Files:
  • string_crypter.h (Header file)
  • string_crypter.c (Implementation)
  • test_string_crypter_c.c (Example usage)
• Usage: Link against string_crypter.c and use process_string_c(char type, const char* data, char** result). Caller must free(*result).
• To Compile & Run Example (e.g., with gcc):

  gcc test_string_crypter_c.c string_crypter.c -o test_c
  ./test_c

7. JavaScript (Node.js & Browser)

• Files:
  • stringCrypter.js (Core logic, supports Node.js require and browser global)
  • testJs.html (Browser test page)
• Usage:
  • Node.js: const sc = require('./stringCrypter.js'); sc.processString('e', "data");
  • Browser: Include stringCrypter.js in a script tag. processString will be available globally.
• To Run (Node.js example):

  node -e "const sc = require('./stringCrypter.js'); console.log(sc.processString('e', 'Hello JS'));"

  To Run (Browser): Open testJs.html in a web browser and check the console.

8. Go

• File: stringcrypter.go
• Usage: Contains ProcessStringGo(operationType rune, data string) and a main function for tests.
• To Run:

  go run stringcrypter.go

9. Rust

• File: string_crypter.rs
• Usage: Contains process_string_rust(operation_type: char, data: &str) and a main function for tests.
• Dependencies (add to Cargo.toml):

  [dependencies]
  base64 = "0.21" # Or latest compatible
  rand = "0.8"    # Or latest compatible
  hex = "0.4"     # Or latest compatible

• To Run (within a Cargo project):

  # Example: cargo new rust_crypto_test && cd rust_crypto_test
  # Replace src/main.rs with string_crypter.rs content
  # Add dependencies to Cargo.toml
  cargo run

10. Lua

• File: string_crypter.lua
• Usage: Returns a module table. Use M.process_string_lua(type, data). Contains test examples.
• Requirements: Lua 5.3+ recommended for bit32 library. For older versions, an external bitwise operations library might be needed.
• To Run:

  lua string_crypter.lua

11. Kotlin

• File: StringCrypter.kt
• Usage: Contains processStringKt(type: Char, data: String) and a main function for tests.
• To Run: Requires Kotlin compiler.

  kotlinc StringCrypter.kt -include-runtime -d StringCrypterKt.jar
  java -jar StringCrypterKt.jar

12. Dart (and Flutter)

• File: string_crypter.dart
• Usage: Contains processStringDart(String type, String data) and a main function for tests.
  • Dart CLI: Run directly.
  • Flutter: Copy string_crypter.dart into your Flutter project's lib directory and import it.
• To Run (Dart CLI):

  dart string_crypter.dart

13. Swift

• File: StringCrypter.swift
• Usage: Contains processStringSwift(type: Character, data: String) and a runSwiftTests() function.
• To Run: Requires Swift compiler.

  swift StringCrypter.swift

  (Or run in an Xcode Playground.)

14. Ruby

• File: string_crypter.rb
• Usage: Contains process_string_rb(type, data) and test code within if __FILE__ == $0.
• To Run:

  ruby string_crypter.rb

15. Perl

• File: string_crypter.pl
• Usage: Contains process_string_pl($type, $data) and test code.
• Requirements: MIME::Base64 and Encode modules (Encode is usually core).
• To Run:

  perl string_crypter.pl

  (Install modules if needed: cpan MIME::Base64)
• Interoperability Note: The current Perl implementation (string_crypter.pl) has a deviation from the common scheme. It prepends the raw 16 salt bytes to the UTF-8 encoded plaintext before XORing. For full interoperability, the Perl script should be modified to prepend the 32-character hex string representation of the salt to the plaintext string before the combined string is UTF-8 encoded (i.e., encode_utf8(salt_hex_string . plaintext) should be the data fed to XOR).

16. Scala

• File: StringCrypter.scala
• Usage: An object StringCrypter with processStringScala(operationType: Char, data: String) and a main method for tests.
• To Run: Requires Scala compiler.

  scalac StringCrypter.scala
  scala StringCrypter

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Interoperability Testing

Each implementation includes placeholder tests for decrypting a string encrypted by another language (often Python as an example). To properly test interoperability:

1. Encrypt a known string (e.g., "Hello from [SourceLanguage] for [TargetLanguage]!") using the source language script.
2. Copy the resulting Base64 encoded string.
3. Replace the placeholder *_encrypted variable in the target language's test section with this string.
4. Run the target language's test script to verify successful decryption.

Similarly, each script generates an encrypted string that can be used to test decryption in other languages.

Contributing

Feel free to add implementations in other languages or improve existing ones! Please ensure the core encryption logic remains consistent for interoperability. If you encounter issues or have suggestions, please open an issue or a pull request.