Repository: Pakhee/Cross-platform-AES-encryption
Branch: master
Commit: 823f3ae081d2
Files: 18
Total size: 67.9 KB

Directory structure:
gitextract_ogl9ndbr/

├── .gitignore
├── Android/
│   ├── CryptLib.java
│   └── Usage.txt
├── C-Sharp/
│   ├── CryptLib.cs
│   └── HowToUse.cs
├── LICENSE
├── Node/
│   ├── README.md
│   ├── dist/
│   │   └── CryptLib.js
│   ├── gulpfile.js
│   ├── index.js
│   ├── package.json
│   ├── src/
│   │   └── CryptLib.js
│   └── test/
│       └── CryptLib-test.js
├── README.md
└── iOS/
    ├── CryptLib.h
    ├── CryptLib.m
    ├── NSData+Base64.h
    └── NSData+Base64.m

================================================
FILE CONTENTS
================================================

================================================
FILE: .gitignore
================================================
Node/node_modules


================================================
FILE: Android/CryptLib.java
================================================
package com.pakhee.common;

import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;
import android.util.Base64;

	/*****************************************************************
	 * CrossPlatform CryptLib
	 * 
	 * <p>
	 * This cross platform CryptLib uses AES 256 for encryption. This library can
	 * be used for encryptoion and de-cryption of string on iOS, Android and Windows
	 * platform.<br/>
	 * Features: <br/>
	 * 1. 256 bit AES encryption
	 * 2. Random IV generation. 
	 * 3. Provision for SHA256 hashing of key. 
	 * </p>
	 * 
	 * @since 1.0
	 * @author navneet
	 *****************************************************************/
	 
public class CryptLib {

	/**
	 * Encryption mode enumeration
	 */
	private enum EncryptMode {
		ENCRYPT, DECRYPT;
	}

	// cipher to be used for encryption and decryption
	Cipher _cx;

	// encryption key and initialization vector
	byte[] _key, _iv;

	public CryptLib() throws NoSuchAlgorithmException, NoSuchPaddingException {
		// initialize the cipher with transformation AES/CBC/PKCS5Padding
		_cx = Cipher.getInstance("AES/CBC/PKCS5Padding");
		_key = new byte[32]; //256 bit key space
		_iv = new byte[16]; //128 bit IV
	}
	
	/**
	 * Note: This function is no longer used. 
	 * This function generates md5 hash of the input string
	 * @param inputString
	 * @return md5 hash of the input string
	 */
	public static final String md5(final String inputString) {
	    final String MD5 = "MD5";
	    try {
	        // Create MD5 Hash
	        MessageDigest digest = java.security.MessageDigest
	                .getInstance(MD5);
	        digest.update(inputString.getBytes());
	        byte messageDigest[] = digest.digest();

	        // Create Hex String
	        StringBuilder hexString = new StringBuilder();
	        for (byte aMessageDigest : messageDigest) {
	            String h = Integer.toHexString(0xFF & aMessageDigest);
	            while (h.length() < 2)
	                h = "0" + h;
	            hexString.append(h);
	        }
	        return hexString.toString();

	    } catch (NoSuchAlgorithmException e) {
	        e.printStackTrace();
	    }
	    return "";
	}
	
	/**
	 * 
	 * @param _inputText
	 *            Text to be encrypted or decrypted
	 * @param _encryptionKey
	 *            Encryption key to used for encryption / decryption
	 * @param _mode
	 *            specify the mode encryption / decryption
	 * @param _initVector
	 * 	      Initialization vector
	 * @return encrypted or decrypted string based on the mode
	 * @throws UnsupportedEncodingException
	 * @throws InvalidKeyException
	 * @throws InvalidAlgorithmParameterException
	 * @throws IllegalBlockSizeException
	 * @throws BadPaddingException
	 */
	 	private String encryptDecrypt(String _inputText, String _encryptionKey,
			EncryptMode _mode, String _initVector) throws UnsupportedEncodingException,
			InvalidKeyException, InvalidAlgorithmParameterException,
			IllegalBlockSizeException, BadPaddingException {
		String _out = "";// output string
		//_encryptionKey = md5(_encryptionKey);
		//System.out.println("key="+_encryptionKey);
		
		int len = _encryptionKey.getBytes("UTF-8").length; // length of the key	provided
		
		if (_encryptionKey.getBytes("UTF-8").length > _key.length)
			len = _key.length;
		
		int ivlen = _initVector.getBytes("UTF-8").length;
		
		if(_initVector.getBytes("UTF-8").length > _iv.length)
			ivlen = _iv.length;
		
		System.arraycopy(_encryptionKey.getBytes("UTF-8"), 0, _key, 0, len);
		System.arraycopy(_initVector.getBytes("UTF-8"), 0, _iv, 0, ivlen);
		//KeyGenerator _keyGen = KeyGenerator.getInstance("AES");
		//_keyGen.init(128);

		SecretKeySpec keySpec = new SecretKeySpec(_key, "AES"); // Create a new SecretKeySpec
									// for the
									// specified key
									// data and
									// algorithm
									// name.
		
		IvParameterSpec ivSpec = new IvParameterSpec(_iv); // Create a new
								// IvParameterSpec
								// instance with the
								// bytes from the
								// specified buffer
								// iv used as
								// initialization
								// vector.

		// encryption
		if (_mode.equals(EncryptMode.ENCRYPT)) {
			// Potentially insecure random numbers on Android 4.3 and older.
			// Read
			// https://android-developers.blogspot.com/2013/08/some-securerandom-thoughts.html
			// for more info.
			_cx.init(Cipher.ENCRYPT_MODE, keySpec, ivSpec);// Initialize this cipher instance
			byte[] results = _cx.doFinal(_inputText.getBytes("UTF-8")); // Finish
										// multi-part
										// transformation
										// (encryption)
			_out = Base64.encodeToString(results, Base64.DEFAULT); // ciphertext
										// output
		}

		// decryption
		if (_mode.equals(EncryptMode.DECRYPT)) {
			_cx.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);// Initialize this ipher instance
			
			byte[] decodedValue = Base64.decode(_inputText.getBytes(),
					Base64.DEFAULT);
			byte[] decryptedVal = _cx.doFinal(decodedValue); // Finish
									// multi-part
									// transformation
									// (decryption)
			_out = new String(decryptedVal);
		}
		System.out.println(_out);
		return _out; // return encrypted/decrypted string
	}

	/***
	 * This function computes the SHA256 hash of input string
	 * @param text input text whose SHA256 hash has to be computed
	 * @param length length of the text to be returned
	 * @return returns SHA256 hash of input text 
	 * @throws NoSuchAlgorithmException
	 * @throws UnsupportedEncodingException
	 */
	public static String SHA256 (String text, int length) throws NoSuchAlgorithmException, UnsupportedEncodingException {

	    String resultStr;
		MessageDigest md = MessageDigest.getInstance("SHA-256");

	    md.update(text.getBytes("UTF-8"));
	    byte[] digest = md.digest();
	    
	    StringBuffer result = new StringBuffer();
	    for (byte b : digest) {
	        result.append(String.format("%02x", b)); //convert to hex
	    }
	    //return result.toString();
	    
	    if(length > result.toString().length())
	    {
	    	resultStr = result.toString();
	    }
	    else 
	    {
	    	resultStr = result.toString().substring(0, length);
	    }

	    return resultStr;
	    
	}
	
	/***
	 * This function encrypts the plain text to cipher text using the key
	 * provided. You'll have to use the same key for decryption
	 * 
	 * @param _plainText
	 *            Plain text to be encrypted
	 * @param _key
	 *            Encryption Key. You'll have to use the same key for decryption
	 * @param _iv
	 * 	    initialization Vector
	 * @return returns encrypted (cipher) text
	 * @throws InvalidKeyException
	 * @throws UnsupportedEncodingException
	 * @throws InvalidAlgorithmParameterException
	 * @throws IllegalBlockSizeException
	 * @throws BadPaddingException
	 */
	 
	public String encrypt(String _plainText, String _key, String _iv)
			throws InvalidKeyException, UnsupportedEncodingException,
			InvalidAlgorithmParameterException, IllegalBlockSizeException,
			BadPaddingException {
		return encryptDecrypt(_plainText, _key, EncryptMode.ENCRYPT, _iv);
	}
	
	/***
	 * This funtion decrypts the encrypted text to plain text using the key
	 * provided. You'll have to use the same key which you used during
	 * encryprtion
	 * 
	 * @param _encryptedText
	 *            Encrypted/Cipher text to be decrypted
	 * @param _key
	 *            Encryption key which you used during encryption
	 * @param _iv
	 * 	    initialization Vector
	 * @return encrypted value
	 * @throws InvalidKeyException
	 * @throws UnsupportedEncodingException
	 * @throws InvalidAlgorithmParameterException
	 * @throws IllegalBlockSizeException
	 * @throws BadPaddingException
	 */
	public String decrypt(String _encryptedText, String _key, String _iv)
			throws InvalidKeyException, UnsupportedEncodingException,
			InvalidAlgorithmParameterException, IllegalBlockSizeException,
			BadPaddingException {
		return encryptDecrypt(_encryptedText, _key, EncryptMode.DECRYPT, _iv);
	}
	
	/**
 	* this function generates random string for given length
 	* @param length
 	* 				Desired length
 	* * @return 
 	*/
	public static String generateRandomIV(int length)
	{
		SecureRandom ranGen = new SecureRandom();
		byte[] aesKey = new byte[16];
		ranGen.nextBytes(aesKey);
		StringBuffer result = new StringBuffer();
	    for (byte b : aesKey) {
	        result.append(String.format("%02x", b)); //convert to hex
	    }
	    if(length> result.toString().length())
	    {
	    	return result.toString();
	    }
	    else
	    {
	    	return result.toString().substring(0, length);
	    }
	}
}


================================================
FILE: Android/Usage.txt
================================================
//This is how to use CryptLib.java

	   try {
	    	CryptLib _crypt = new CryptLib();
	    	String output= "";
	    	String plainText = "This is the text to be encrypted.";
	    	String key = CryptLib.SHA256("my secret key", 32); //32 bytes = 256 bit
	    	String iv = CryptLib.generateRandomIV(16); //16 bytes = 128 bit
	    	output = _crypt.encrypt(plainText, key, iv); //encrypt
	    	System.out.println("encrypted text=" + output);
	    	output = _crypt.decrypt(output, key,iv); //decrypt
	    	System.out.println("decrypted text=" + output);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
If you are getting "java.security.InvalidKeyException: Illegal key size" error while compiling, see this - http://stackoverflow.com/questions/6481627/java-security-illegal-key-size-or-default-parameters


================================================
FILE: C-Sharp/CryptLib.cs
================================================
using System;
using System.Text;
using System.Security.Cryptography;

namespace com.pakhee.common
{
	/*****************************************************************
	 * CrossPlatform CryptLib
	 * 
	 * <p>
	 * This cross platform CryptLib uses AES 256 for encryption. This library can
	 * be used for encryptoion and de-cryption of string on iOS, Android and Windows
	 * platform.<br/>
	 * Features: <br/>
	 * 1. 256 bit AES encryption
	 * 2. Random IV generation. 
	 * 3. Provision for SHA256 hashing of key. 
	 * </p>
	 * 
	 * @since 1.0
	 * @author navneet
	 *****************************************************************/
	public class CryptLib
	{
		UTF8Encoding _enc;
		RijndaelManaged _rcipher;
		byte[] _key, _pwd, _ivBytes, _iv;
		
		/***
		 * Encryption mode enumeration
		 */
		private enum EncryptMode {ENCRYPT, DECRYPT};
		
		static readonly char[] CharacterMatrixForRandomIVStringGeneration = {
			'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 
			'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 
			'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 
			'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 
			'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'
		};
		
		/**
		 * This function generates random string of the given input length.
		 * 
		 * @param _plainText
		 *            Plain text to be encrypted
		 * @param _key
		 *            Encryption Key. You'll have to use the same key for decryption
		 * @return returns encrypted (cipher) text
		 */
		internal static string GenerateRandomIV(int length) {
			char[] _iv = new char[length];
			byte[] randomBytes = new byte[length];

			using (RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider()) {
				rng.GetBytes(randomBytes); //Fills an array of bytes with a cryptographically strong sequence of random values. 
			}

			for (int i = 0; i < _iv.Length; i++) {
				int ptr = randomBytes[i] % CharacterMatrixForRandomIVStringGeneration.Length;
				_iv[i] = CharacterMatrixForRandomIVStringGeneration[ptr];
			}

			return new string(_iv);
		}
		
		

		public CryptLib()
		{
			_enc = new UTF8Encoding();
			_rcipher =  new RijndaelManaged();
			_rcipher.Mode = CipherMode.CBC;
			_rcipher.Padding = PaddingMode.PKCS7;
			_rcipher.KeySize = 256;
			_rcipher.BlockSize = 128;
			_key = new byte[32];
			_iv = new byte[_rcipher.BlockSize/8]; //128 bit / 8 = 16 bytes
			_ivBytes =  new byte[16];
		}

		/**
		 * 
		 * @param _inputText
		 *            Text to be encrypted or decrypted
		 * @param _encryptionKey
		 *            Encryption key to used for encryption / decryption
		 * @param _mode
		 *            specify the mode encryption / decryption
		 * @param _initVector
		 * 			  initialization vector
		 * @return encrypted or decrypted string based on the mode
	 	*/
		private String encryptDecrypt (string _inputText, string _encryptionKey, EncryptMode _mode, string _initVector)
		{

			string _out = "";// output string
			//_encryptionKey = MD5Hash (_encryptionKey);
			_pwd = Encoding.UTF8.GetBytes(_encryptionKey);
			_ivBytes = Encoding.UTF8.GetBytes (_initVector);

			int len = _pwd.Length;
			if (len > _key.Length)
			{
				len = _key.Length;
			}
			int ivLenth = _ivBytes.Length;
			if (ivLenth > _iv.Length) 
			{
				ivLenth = _iv.Length;		
			}

			Array.Copy(_pwd, _key, len);
			Array.Copy (_ivBytes, _iv, ivLenth);
			_rcipher.Key = _key;
			_rcipher.IV = _iv;

			if (_mode.Equals (EncryptMode.ENCRYPT)) {
				//encrypt
				byte[] plainText = _rcipher.CreateEncryptor().TransformFinalBlock(_enc.GetBytes(_inputText) , 0, _inputText.Length);
				_out = Convert.ToBase64String(plainText);
			}
			if (_mode.Equals (EncryptMode.DECRYPT)) {
				//decrypt
				byte[] plainText = _rcipher.CreateDecryptor().TransformFinalBlock(Convert.FromBase64String(_inputText), 0, Convert.FromBase64String(_inputText).Length);
				_out = _enc.GetString(plainText);
			}
			_rcipher.Dispose();
			return _out;// return encrypted/decrypted string
		}

		/**
		 * This function encrypts the plain text to cipher text using the key
		 * provided. You'll have to use the same key for decryption
		 * 
		 * @param _plainText
		 *            Plain text to be encrypted
		 * @param _key
		 *            Encryption Key. You'll have to use the same key for decryption
		 * @return returns encrypted (cipher) text
		 */
		public string encrypt (string _plainText, string _key, string _initVector)
		{
			return encryptDecrypt(_plainText, _key, EncryptMode.ENCRYPT, _initVector);
		}

		/***
		 * This funtion decrypts the encrypted text to plain text using the key
		 * provided. You'll have to use the same key which you used during
		 * encryprtion
		 * 
		 * @param _encryptedText
		 *            Encrypted/Cipher text to be decrypted
		 * @param _key
		 *            Encryption key which you used during encryption
		 * @return encrypted value
		 */
		 
		public string decrypt(string _encryptedText, string _key, string _initVector)
		{
			return encryptDecrypt(_encryptedText, _key, EncryptMode.DECRYPT, _initVector);
		}

		/***
		 * This function decrypts the encrypted text to plain text using the key
		 * provided. You'll have to use the same key which you used during
		 * encryption
		 * 
		 * @param _encryptedText
		 *            Encrypted/Cipher text to be decrypted
		 * @param _key
		 *            Encryption key which you used during encryption
		 */
		public static string getHashSha256(string text, int length)
		{
			byte[] bytes = Encoding.UTF8.GetBytes(text);
			SHA256Managed hashstring = new SHA256Managed();
			byte[] hash = hashstring.ComputeHash(bytes);
			string hashString = string.Empty;
			foreach (byte x in hash)
			{
				hashString += String.Format("{0:x2}", x); //covert to hex string
			}
			if (length > hashString.Length)
				return hashString;
			else
				return hashString.Substring (0, length);
		}
		
		//this function is no longer used.
		private static string MD5Hash(string text)
		{
			MD5 md5 = new MD5CryptoServiceProvider();

			//compute hash from the bytes of text
			md5.ComputeHash(ASCIIEncoding.ASCII.GetBytes(text));

			//get hash result after compute it
			byte[] result = md5.Hash;

			StringBuilder strBuilder = new StringBuilder();
			for (int i = 0; i < result.Length; i++)
			{
				//change it into 2 hexadecimal digits
				//for each byte
				strBuilder.Append(result[i].ToString("x2"));
			}
			Console.WriteLine ("md5 hash of they key=" + strBuilder.ToString ());
			return strBuilder.ToString();
		}

	}
}


================================================
FILE: C-Sharp/HowToUse.cs
================================================
	public class test {
		public static void Main (String []args)
		{
			CryptLib _crypt = new CryptLib ();
			string plainText = "This is the text to be encrypted";
			String iv = CryptLib.GenerateRandomIV (16); //16 bytes = 128 bits
			string key = CryptLib.getHashSha256("my secret key", 31); //32 bytes = 256 bits
			String cypherText = _crypt.encrypt (plainText, key, iv);
			Console.WriteLine ("iv="+iv);
			Console.WriteLine ("key=" + key);
			Console.WriteLine("Cypher text=" + cypherText);
			Console.WriteLine ("Plain text =" + _crypt.decrypt (cypherText, key, iv));
		}

	}


================================================
FILE: LICENSE
================================================
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      unless required by applicable law (such as deliberate and grossly
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   Copyright 2015 NAVNEET KUMAR

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

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   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.


================================================
FILE: Node/README.md
================================================
CryptLib
=========

A module to encrypt/decrypt string in Node, written in ES6 (src folder) and transpiled using Babel to ES5(dist folder).

Using companion framework libraries, you should be able to encrypt/decrypt between node, iOS, Android and Windows platforms.

Companion libs can be found here: https://github.com/Pakhee/Cross-platform-AES-encryption


## Installation

  npm install cryptlib --save

## Usage

	var CryptLib = require('cryptlib'),
		_crypt = new CryptLib(),
		plainText = 'This is the text to be encrypted',
		iv = _crypt.generateRandomIV(16), //16 bytes = 128 bit
		key = _crypt.getHashSha256('my secret key', 32), //32 bytes = 256 bits
		cypherText = _crypt.encrypt(plainText, key, iv),
        originalText = _crypt.decrypt(cypherText, key, iv);

## Run Code Sample
  
  npm start

## Tests

  npm test

## Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style.
Add unit tests for any new or changed functionality. Lint and test your code.

## Release History

* 0.1.0 Initial release

## License

Apache License; see [LICENSE](../LICENSE).

(c) 2015 by Abdul Khan


================================================
FILE: Node/dist/CryptLib.js
================================================

/*global console*/
'use strict';

Object.defineProperty(exports, '__esModule', {
  value: true
});

var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }

var _crypto = require('crypto');

var _crypto2 = _interopRequireDefault(_crypto);

var _bl = require('bl');

var _bl2 = _interopRequireDefault(_bl);

var _lodashIsarray = require('lodash.isarray');

var _lodashIsarray2 = _interopRequireDefault(_lodashIsarray);

/**
 * CrossPlatform CryptLib
   * This cross platform CryptLib uses AES 256 for encryption. This library can
   * be used for encryption and de-cryption of strings on iOS, Android, Windows
   * and Node platform.
   * Features:
   * 1. 256 bit AES encryption
   * 2. Random IV generation. 
   * 3. Provision for SHA256 hashing of key. 
 */

var CryptLib = (function () {
  function CryptLib() {
    _classCallCheck(this, CryptLib);

    this._maxKeySize = 32;
    this._maxIVSize = 16;
    this._algorithm = 'AES-256-CBC';
    this._characterMatrixForRandomIVStringGeneration = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'];
  }

  _createClass(CryptLib, [{
    key: '_encryptDecrypt',

    /**
     * private function: _encryptDecrypt
     * encryptes or decrypts to or from text or encrypted text given an iv and key
     * @param  {string}  text        can be plain text or encrypted text
     * @param  {string}  key         the key used to encrypt or decrypt 
     * @param  {string}  initVector  the initialization vector to encrypt or 
     *                               decrypt
     * @param  {bool}    isEncrypt   true = encryption, false = decryption
     * @return {string}              encryted text or plain text 
     */
    value: function _encryptDecrypt(text, key, initVector, isEncrypt) {

      if (!text || !key) {
        throw 'cryptLib._encryptDecrypt: -> key and plain or encrypted text ' + 'required';
      }

      var ivBl = new _bl2['default'](),
          keyBl = new _bl2['default'](),
          keyCharArray = key.split(''),
          ivCharArray = [],
          encryptor = undefined,
          decryptor = undefined,
          clearText = undefined;

      if (initVector && initVector.length > 0) {
        ivCharArray = initVector.split('');
      }

      for (var i = 0; i < this._maxIVSize; i++) {
        ivBl.append(ivCharArray.shift() || [null]);
      }

      for (var i = 0; i < this._maxKeySize; i++) {
        keyBl.append(keyCharArray.shift() || [null]);
      }

      if (isEncrypt) {
        encryptor = _crypto2['default'].createCipheriv(this._algorithm, keyBl.toString(), ivBl.toString());
        encryptor.setEncoding('base64');
        encryptor.write(text);
        encryptor.end();
        return encryptor.read();
      }

      decryptor = _crypto2['default'].createDecipheriv(this._algorithm, keyBl.toString(), ivBl.toString());
      var dec = decryptor.update(text, 'base64', 'utf8');
      dec += decryptor.final('utf8');
      return dec;
    }
  }, {
    key: '_isCorrectLength',

    /**
     * private function: _isCorrectLength 
     * checks if length is preset and is a whole number and > 0
     * @param  {int}  length
     * @return {bool} 
    */
    value: function _isCorrectLength(length) {
      return length && /^\d+$/.test(length) && parseInt(length, 10) !== 0;
    }
  }, {
    key: 'generateRandomIV',

    /**
     * generates random initaliztion vector given a length
     * @param  {int}  length  the length of the iv to be generated
     */
    value: function generateRandomIV(length) {
      if (!this._isCorrectLength(length)) {
        throw 'cryptLib.generateRandomIV() -> needs length or in wrong format';
      }

      length = parseInt(length, 10);
      var _iv = [],
          randomBytes = _crypto2['default'].randomBytes(length);

      for (var i = 0; i < length; i++) {
        var ptr = randomBytes[i] % this._characterMatrixForRandomIVStringGeneration.length;
        _iv[i] = this._characterMatrixForRandomIVStringGeneration[ptr];
      }
      return _iv.join('');
    }
  }, {
    key: 'getHashSha256',

    /**
     * Creates a hash of a key using SHA-256 algorithm
     * @param  {string} key     the key that will be hashed
     * @param  {int}    length  the length of the SHA-256 hash
     * @return {string}         the output hash generated given a key and length
     */
    value: function getHashSha256(key, length) {
      if (!key) {
        throw 'cryptLib.getHashSha256() -> needs key';
      }

      if (!this._isCorrectLength(length)) {
        throw 'cryptLib.getHashSha256() -> needs length or in wrong format';
      }

      return _crypto2['default'].createHash('sha256').update(key).digest('hex').substring(0, length);
    }
  }, {
    key: 'encrypt',

    /**
     * encryptes plain text given a key and initialization vector
     * @param  {string}  text        can be plain text or encrypted text
     * @param  {string}  key         the key used to encrypt or decrypt 
     * @param  {string}  initVector  the initialization vector to encrypt or 
     *                               decrypt
     * @return {string}              encryted text or plain text 
     */
    value: function encrypt(plainText, key, initVector) {
      return this._encryptDecrypt(plainText, key, initVector, true);
    }
  }, {
    key: 'decrypt',

    /**
     * decrypts encrypted text given a key and initialization vector
     * @param  {string}  text        can be plain text or encrypted text
     * @param  {string}  key         the key used to encrypt or decrypt 
     * @param  {string}  initVector  the initialization vector to encrypt or 
     *                               decrypt
     * @return {string}              encryted text or plain text 
     */
    value: function decrypt(encryptedText, key, initVector) {
      return this._encryptDecrypt(encryptedText, key, initVector, false);
    }
  }]);

  return CryptLib;
})();

exports['default'] = CryptLib;
module.exports = exports['default'];

================================================
FILE: Node/gulpfile.js
================================================
var gulp = require('gulp');
var babel = require('gulp-babel');
var mocha = require('gulp-mocha');

gulp.task('babel', function() {
  return gulp.src('src/*.js')
    .pipe(babel())
    .pipe(gulp.dest('dist/'));
});

gulp.task('watch', function() {
  gulp.watch('src/*.js', ['babel']);
});

gulp.task('test', ['babel'], function() {
  return gulp.src(['test/*.js'])
    .pipe(mocha({ reporter: 'spec' }))
    .on('error', function(err) {
        console.log(err.stack);
    });
});

// Default Task
gulp.task('default', ['babel', 'test']);


================================================
FILE: Node/index.js
================================================
/*global require*/

var CryptLib = require('cryptlib'),
    _crypt = new CryptLib(),
    plainText = 'This is the text to be encrypted',
    iv = _crypt.generateRandomIV(16), //16 bytes = 128 bit
    key = _crypt.getHashSha256('my secret key', 32), //32 bytes = 256 bits
    cypherText = _crypt.encrypt(plainText, key, iv);

console.log('iv = %s', iv);
console.log('key = %s', key);
console.log('Cypher text = %s', cypherText);
console.log('Plain text = %s', _crypt.decrypt(cypherText, key, iv));

================================================
FILE: Node/package.json
================================================
{
  "name": "cryptlib",
  "version": "1.0.0",
  "author": {
    "name": "Abdul Khan"
  },
  "main": "dist/CryptLib.js",
  "description": "CryptLib uses AES 256 for encryption or decryption. This library can be used for encryption and decryption of strings using Node on iOS, Android and Windows",
  "contributors": [
    {
      "name": "Abdul Khan",
      "email": "invalidred@gmail.com"
    },
    {
      "name": "Alexey Novak",
      "email": "alexey.novak.mail@gmail.com"
    }
  ],
  "scripts": {
    "start": "node index.js",
    "test": "node node_modules/mocha/bin/mocha --reporter spec test/*"
  },
  "repository": {
    "type": "git",
    "url": "git+ssh://git@github.com:invalidred/Cross-platform-AES-encryption.git"
  },
  "keywords": [
    "AES node",
    "Cross Platform",
    "Encryption",
    "Decryption"
  ],
  "dependencies": {
    "bl": "4.0.3",
    "lodash.isarray": "3.0.4",
    "lodash.isfunction": "3.0.6"
  },
  "devDependencies": {
    "babel": "^5.2.17",
    "chai": "^2.3.0",
    "gulp": "^3.8.11",
    "gulp-babel": "^5.1.0",
    "gulp-mocha": "^2.0.1",
    "mocha": "^2.2.4"
  },
  "engine": "node >= 0.10.x",
  "homepage": "https://github.com/invalidred/Cross-platform-AES-encryption",
  "bugs": {
    "url": "https://github.com/Pakhee/Cross-platform-AES-encryption/issues"
  },
  "private": false,
  "license": "Apache",
  "_npmVersion": "2.5.1",
  "_nodeVersion": "0.12.0",
  "_npmUser": {
    "name": "invalidred",
    "email": "invalidred@gmail.com"
  },
  "maintainers": [
    {
      "name": "Abdul Khan",
      "email": "invalidred@gmail.com"
    }
  ]
}


================================================
FILE: Node/src/CryptLib.js
================================================

/*global console*/
'use strict';

import crypto from 'crypto';
import BufferList from 'bl';
import isArray from 'lodash.isarray';

/**
 * CrossPlatform CryptLib
   * This cross platform CryptLib uses AES 256 for encryption. This library can
   * be used for encryption and de-cryption of strings on iOS, Android, Windows
   * and Node platform.
   * Features:
   * 1. 256 bit AES encryption
   * 2. Random IV generation. 
   * 3. Provision for SHA256 hashing of key. 
 */
export default class CryptLib {

  constructor() {
    this._maxKeySize = 32;
    this._maxIVSize = 16;
    this._algorithm = 'AES-256-CBC';
    this._characterMatrixForRandomIVStringGeneration = [
      'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 
      'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 
      'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 
      'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 
      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_'
    ];
  }

  /**
   * private function: _encryptDecrypt
   * encryptes or decrypts to or from text or encrypted text given an iv and key
   * @param  {string}  text        can be plain text or encrypted text
   * @param  {string}  key         the key used to encrypt or decrypt 
   * @param  {string}  initVector  the initialization vector to encrypt or 
   *                               decrypt
   * @param  {bool}    isEncrypt   true = encryption, false = decryption
   * @return {string}              encryted text or plain text 
   */
  _encryptDecrypt(text, key, initVector, isEncrypt) {

    if (!text || !key) {
      throw 'cryptLib._encryptDecrypt: -> key and plain or encrypted text '+
       'required';
    }

    let ivBl = new BufferList(),
        keyBl = new BufferList(),
        keyCharArray = key.split(''),
        ivCharArray = [],
        encryptor, decryptor, clearText;

    if (initVector && initVector.length > 0) {
       ivCharArray = initVector.split('');
    }
    
    for (var i = 0; i < this._maxIVSize; i++) {
      ivBl.append(ivCharArray.shift() || [null]);
    }

    for (var i = 0; i < this._maxKeySize; i++) {
      keyBl.append(keyCharArray.shift() || [null]);
    }

    if (isEncrypt) {
      encryptor = crypto.createCipheriv(this._algorithm, keyBl.toString(), 
        ivBl.toString());
      encryptor.setEncoding('base64');
      encryptor.write(text);
      encryptor.end();
      return encryptor.read();
    }

    decryptor = crypto.createDecipheriv(this._algorithm, keyBl.toString(),
      ivBl.toString());
    var dec = decryptor.update(text, 'base64', 'utf8');
    dec += decryptor.final('utf8');
    return dec;
  }

  /**
   * private function: _isCorrectLength 
   * checks if length is preset and is a whole number and > 0
   * @param  {int}  length
   * @return {bool} 
  */
  _isCorrectLength(length) {
    return length && /^\d+$/.test(length) && parseInt(length, 10) !== 0
  }

  /**
   * generates random initaliztion vector given a length
   * @param  {int}  length  the length of the iv to be generated
   */
  generateRandomIV(length) {
    if (!this._isCorrectLength(length)) {
      throw 'cryptLib.generateRandomIV() -> needs length or in wrong format';
    }

    length = parseInt(length, 10);
    let _iv = [],
        randomBytes = crypto.randomBytes(length);

    for (let i = 0; i < length; i++) {
      let ptr = randomBytes[i] % 
        this._characterMatrixForRandomIVStringGeneration.length;
      _iv[i] = this._characterMatrixForRandomIVStringGeneration[ptr];
    }
    return _iv.join('');
  }

  /**
   * Creates a hash of a key using SHA-256 algorithm
   * @param  {string} key     the key that will be hashed
   * @param  {int}    length  the length of the SHA-256 hash
   * @return {string}         the output hash generated given a key and length
   */
  getHashSha256(key, length) {
    if (!key) {
      throw 'cryptLib.getHashSha256() -> needs key';
    }

    if (!this._isCorrectLength(length)) {
      throw 'cryptLib.getHashSha256() -> needs length or in wrong format';
    }

    return crypto.createHash('sha256')
                 .update(key)
                 .digest('hex')
                 .substring(0, length);
  }

  /**
   * encryptes plain text given a key and initialization vector
   * @param  {string}  text        can be plain text or encrypted text
   * @param  {string}  key         the key used to encrypt or decrypt 
   * @param  {string}  initVector  the initialization vector to encrypt or 
   *                               decrypt
   * @return {string}              encryted text or plain text 
   */
  encrypt(plainText, key, initVector) {
    return this._encryptDecrypt(plainText, key, initVector, true);
  }

  /**
   * decrypts encrypted text given a key and initialization vector
   * @param  {string}  text        can be plain text or encrypted text
   * @param  {string}  key         the key used to encrypt or decrypt 
   * @param  {string}  initVector  the initialization vector to encrypt or 
   *                               decrypt
   * @return {string}              encryted text or plain text 
   */
  decrypt(encryptedText, key, initVector) {
    return this._encryptDecrypt(encryptedText, key, initVector, false);
  }
}


================================================
FILE: Node/test/CryptLib-test.js
================================================
/*global it, describe, require*/

var chai = require('chai'),
    expect = chai.expect,
    CryptLib = require('../dist/cryptLib.js');

describe('CryptLib', function() {
  var cryptLib;

  before(function() {
    cryptLib = new CryptLib();
  });

  after(function() {
    cryptLib = null;
  });

  describe('generateRandomIV()', function() {
    var errorMessage = 'cryptLib.generateRandomIV() -> needs length or in wrong format';

    it('no length should throw error', function() {
      try {
        cryptLib.generateRandomIV()
      } catch (message) {
        expect(message).to.equal(errorMessage);
      }
    });

    it('non-numeric and non-whole number length should throw error', function() {
      try{
        cryptLib.generateRandomIV('abc');
      } catch (message) {
        expect(message).to.equal(errorMessage);
      }

      try{
        cryptLib.generateRandomIV('12a'); 
      } catch (message) {
        expect(message).to.equal(errorMessage);
      }

      try{
        cryptLib.generateRandomIV('12.2'); 
      } catch (message) {
        expect(message).to.equal(errorMessage);
      }
    });

    it('negative length should throw error', function() {
      try {
        cryptLib.generateRandomIV('-1');
      } catch (message) {
        expect(message).to.equal(errorMessage);
      }
    });

    it('length = 0, should throw error', function() {
      try {
        cryptLib.generateRandomIV(0);
      } catch (message) {
        expect(message).to.equal(errorMessage);
      }

      try {
        cryptLib.generateRandomIV('0');
      } catch (message) {
        expect(message).to.equal(errorMessage);
      }
    });

    it('length = 2', function() {
      var iv = cryptLib.generateRandomIV(2);
      expect(iv).to.have.length(2);
      expect(iv).to.be.string;
    });

    it('length = 100', function() {
      var iv = cryptLib.generateRandomIV(100);
      expect(iv).to.have.length(100);
      expect(iv).to.be.string;
    });
  });

  describe('getHashSha256()', function() {
    var lengthErrorMessage = 'cryptLib.getHashSha256() -> needs length or in wrong format',
        keyErrorMessage = 'cryptLib.getHashSha256() -> needs key',
        validKey = 'key';

    it('no key should throw error', function() {
      try {
        cryptLib.getHashSha256(null,2);
      } catch (message) {
        expect(message).to.equal(keyErrorMessage);
      }
    });

    it('no length should throw error', function() {
      try {
        cryptLib.getHashSha256(validKey, null);
      } catch (message) {
        expect(message).to.equal(lengthErrorMessage);
      }
    });

    it('non-numeric and non-whole number length should throw error', function() {
      try{
        cryptLib.getHashSha256(validKey, 'abc');
      } catch (message) {
        expect(message).to.equal(lengthErrorMessage);
      }

      try{
        cryptLib.getHashSha256(validKey, '12a'); 
      } catch (message) {
        expect(message).to.equal(lengthErrorMessage);
      }

      try{
        cryptLib.getHashSha256(validKey, '12.2'); 
      } catch (message) {
        expect(message).to.equal(lengthErrorMessage);
      }
    });

    it('negative length should throw error', function() {
      try {
        cryptLib.getHashSha256(validKey, '-1');
      } catch (message) {
        expect(message).to.equal(lengthErrorMessage);
      }

      try {
        cryptLib.getHashSha256(validKey, -1);
      } catch (message) {
        expect(message).to.equal(lengthErrorMessage);
      }
    });

    it('length = 0, should throw error', function() {
      try {
        cryptLib.getHashSha256(validKey, 0);
      } catch (message) {
        expect(message).to.equal(lengthErrorMessage);
      }

      try {
        cryptLib.getHashSha256(validKey, '0');
      } catch (message) {
        expect(message).to.equal(lengthErrorMessage);
      }
    });

    it('valid key with length = 2', function() {
      var sha = cryptLib.getHashSha256(validKey, 2);
      expect(sha).to.have.length(2);
      expect(sha).to.be.string;
    });

    it('valid key with length = 64', function() {
      var sha = cryptLib.getHashSha256(validKey, 64);
      expect(sha).to.have.length(64);
      expect(sha).to.be.string;
    });

    it('valid key with length = 100 should return 64 char sha', function() {
      var sha = cryptLib.getHashSha256(validKey, 100);
      expect(sha).to.have.length(64);
      expect(sha).to.be.string;
    });
  });

  describe('encrypt() and decrypt() tests', function() {
    var errorMessage = 'cryptLib._encryptDecrypt: -> key and plain or encrypted text required',
        plainText = 'This is the plain text that will be encrypted and decrypted',
        myKey = 'myKey';

    it('encrypt() with no plain text should throw error', function() {
      try {
        cryptLib.encrypt(null, 'key123', 'iv123');
      } catch(error) {
        expect(error).to.equal(errorMessage);
      }
    });

    it('encrypt() with no key should throw error', function() {
      try {
        cryptLib.encrypt(plainText, null, 'iv123');
      } catch(error) {
        expect(error).to.equal(errorMessage);
      }
    });

    it('basic encrypt() decrypt() locally : 0 char iv and 2 char key', function() {
      var iv = '',
          keyHashed = cryptLib.getHashSha256(myKey, 2),
          encryptedText = cryptLib.encrypt(plainText, keyHashed, iv),
          regularText = cryptLib.decrypt(encryptedText, keyHashed, iv);
      expect(regularText).to.equal(plainText);
    });

    it('basic encrypt() decrypt() locally : 2 char iv and 2 char key', function() {
      var iv = cryptLib.generateRandomIV(2),
          keyHashed = cryptLib.getHashSha256(myKey, 2),
          encryptedText = cryptLib.encrypt(plainText, keyHashed, iv),
          decryptedText = cryptLib.decrypt(encryptedText, keyHashed, iv);
      expect(decryptedText).to.equal(plainText);
    });

    it('basic encrypt() decrypt() locally : 16 char iv and 32 char key', function() {
      var iv = cryptLib.generateRandomIV(16),
          keyHashed = cryptLib.getHashSha256(myKey, 32),
          encryptedText = cryptLib.encrypt(plainText, keyHashed, iv),
          decryptedText = cryptLib.decrypt(encryptedText, keyHashed, iv);
      expect(decryptedText).to.equal(plainText);
    });

    it('basic encrypt() decrypt() locally : 20 char iv and 80 char key', function() {
      var iv = cryptLib.generateRandomIV(20),
          keyHashed = cryptLib.getHashSha256(myKey, 80),
          encryptedText = cryptLib.encrypt(plainText, keyHashed, iv),
          decryptedText = cryptLib.decrypt(encryptedText, keyHashed, iv);
      expect(decryptedText).to.equal(plainText);
    });

    it('decrypt 0 char iv and 2 char key generated by c#', function() {
      var cSharpIv = '',
          cSharpKey = 'b1',
          cSharpPlainText = 'C# text that\'s going to be decrypted',
          cSharpCipher = 'M2rfrn9DqNHJe3Hev9nMxKKgIHoqUsc7FJM+tBGxIrl3Wk9UeKIQ5fRUUZF3q2i5',
          nodeDecrpytedText;
      nodeDecrpytedText = cryptLib.decrypt(cSharpCipher, cSharpKey, cSharpIv);
      expect(nodeDecrpytedText).to.equal(cSharpPlainText);
    });

    it('decrypt 2 char iv and 2 char key generated by c#', function() {
      var cSharpIv = 'sA',
          cSharpKey = 'b1',
          cSharpPlainText = 'C# text that\'s going to be decrypted',
          cSharpCipher = '90iAiA80rSiyEoCAnLC9KNYt41koQKs2Lo5NzciyELkoZGne+BAv1ScMXSWETyAL',
          nodeDecrpytedText;
      nodeDecrpytedText = cryptLib.decrypt(cSharpCipher, cSharpKey, cSharpIv);
      expect(nodeDecrpytedText).to.equal(cSharpPlainText);
    });

    it('decrypt 16 char iv and 32 char key generated by c#', function() {
      var cSharpIv = 'HCHXjb_wIURjCV3G',
          cSharpKey = 'b16920894899c7780b5fc7161560a412',
          cSharpPlainText = 'C# text that\'s going to be decrypted',
          cSharpCipher = '0kv/H19UoAN21Et5jSNTM/yKQAaEPiB5Y6qugTQs3kvNuwMLBiOeFwMFnYr9KZBa',
          nodeDecrpytedText;
      nodeDecrpytedText = cryptLib.decrypt(cSharpCipher, cSharpKey, cSharpIv);
      expect(nodeDecrpytedText).to.equal(cSharpPlainText);
    });
  });

});



================================================
FILE: README.md
================================================
Cross platform 256bit AES encryption / decryption.
========
This project contains the implementation of 256 bit AES encryption which works on all the platforms (C#, iOS, Android and Node.js). One of the key objective is to make AES work on all the platforms with simple implementation. 

<b>Platforms Supported:</b>

1. iOS

2. Android

3. Windows (C#).

4. Node.js

<b>Features:</b>

1. Cross platform support. Encryption-Decryption works across C#, iOS, Android and Node.js. 

2. Support for Random IV (initialization vector) for encryption and decryption. Randomization is crucial for encryption schemes to achieve semantic security, a property whereby repeated usage of the scheme under the same key does not allow an attacker to infer relationships between segments of the encrypted message.

3.  Support for SHA-256 for hashing the key. Never use plain text as encryption key. Always hash the plain text key and then use for encryption. AES permits the use of 256-bit keys. Breaking a symmetric 256-bit key by brute force requires 2^128 times more computational power than a 128-bit key. A device that could check a billion billion (10^18) AES keys per second would in theory require about 3×10^51 years to exhaust the 256-bit key space.

<b>How to encrypt a string:</b>

See code samples for more details. You'll have to perform following steps:

1. Generate Ramdom IV using the provided randomIV generator function.
2. Select a secret key and hash it using the provided SHA-256 hash function.
3. Encrypt your string using the hashed key and random IV. 

<b>How to decrypt a string:</b>

See code samples for more details. You'll have to perform following steps:

1. Get the encrypted text and the randomIV used for encryption
2. Decrypt the string using the provided decrypt function !


================================================
FILE: iOS/CryptLib.h
================================================
//
//  CryptLib.h
//

#import <CommonCrypto/CommonDigest.h>
#import <CommonCrypto/CommonCryptor.h>


@interface StringEncryption : NSObject

-  (NSData *)encrypt:(NSData *)plainText key:(NSString *)key iv:(NSString *)iv;
-  (NSData *)decrypt:(NSData *)encryptedText key:(NSString *)key iv:(NSString *)iv;
-  (NSData *)generateRandomIV:(size_t)length;
-  (NSString *) md5:(NSString *) input;
-  (NSString*) sha256:(NSString *)key length:(NSInteger) length;

@end


================================================
FILE: iOS/CryptLib.m
================================================
	/*****************************************************************
	 * CrossPlatform CryptLib
	 * 
	 * <p>
	 * This cross platform CryptLib uses AES 256 for encryption. This library can
	 * be used for encryptoion and de-cryption of string on iOS, Android and Windows
	 * platform.<br/>
	 * Features: <br/>
	 * 1. 256 bit AES encryption
	 * 2. Random IV generation. 
	 * 3. Provision for SHA256 hashing of key. 
	 * </p>
	 * 
	 * @since 1.0
	 * @author navneet
	 *****************************************************************/
// How to use :
// //  1. Encryption:

// NSString * _secret = @"This the sample text has to be encrypted"; // this is the text that you want to encrypt.

// NSString * _key = @"shared secret"; //secret key for encryption. To make encryption stronger, we will not use this key directly. We'll first hash the key next step and then use it.

// key = [[StringEncryption alloc] sha256:key length:32]; //this is very important, 32 bytes = 256 bit

// NSString * iv =   [[[[StringEncryption alloc] generateRandomIV:11]  base64EncodingWithLineLength:0] substringToIndex:16]; //Here we are generating random initialization vector (iv). Length of this vector = 16 bytes = 128 bits

// Now that we have input text, hashed key and random IV, we are all set for encryption:
// NSData * encryptedData = [[StringEncryption alloc] encrypt:[secret dataUsingEncoding:NSUTF8StringEncoding] key:key iv:iv];

// NSLog(@"encrypted data:: %@", [encryptedData  base64EncodingWithLineLength:0]); //print the encrypted text
// Encryption = [plainText + secretKey + randomIV] = Cyphertext

// // 2. Decryption
// for decryption, you will have to use the same IV and key which was used for encryption.

// encryptedData = [[StringEncryption alloc] decrypt:encryptedData  key:key iv:iv];
// NSString * decryptedText = [[NSString alloc] initWithData:encryptedData encoding:NSUTF8StringEncoding];
// NSLog(@"decrypted data:: %@", decryptedText); //print the decrypted text

// For base64EncodingWithLineLength refer - https://github.com/jdg/MGTwitterEngine/blob/master/NSData%2BBase64.m


#import "CryptLib.h"
#import "NSData+Base64.h"


@implementation StringEncryption

- (NSData *)encrypt:(NSData *)plainText key:(NSString *)key  iv:(NSString *)iv {
    char keyPointer[kCCKeySizeAES256+2],// room for terminator (unused) ref: https://devforums.apple.com/message/876053#876053
    ivPointer[kCCBlockSizeAES128+2];
    BOOL patchNeeded;
    bzero(keyPointer, sizeof(keyPointer)); // fill with zeroes for padding
    //key = [[StringEncryption alloc] md5:key];
    patchNeeded= ([key length] > kCCKeySizeAES256+1);
    if(patchNeeded)
    {
        NSLog(@"Key length is longer %lu", (unsigned long)[[[StringEncryption alloc] md5:key] length]);
        key = [key substringToIndex:kCCKeySizeAES256]; // Ensure that the key isn't longer than what's needed (kCCKeySizeAES256)
    }
    
    //NSLog(@"md5 :%@", key);
    [key getCString:keyPointer maxLength:sizeof(keyPointer) encoding:NSUTF8StringEncoding];
    [iv getCString:ivPointer maxLength:sizeof(ivPointer) encoding:NSUTF8StringEncoding];
    
    if (patchNeeded) {
        keyPointer[0] = '\0';  // Previous iOS version than iOS7 set the first char to '\0' if the key was longer than kCCKeySizeAES256
    }
    
    NSUInteger dataLength = [plainText length];
    
    //see https://developer.apple.com/library/ios/documentation/System/Conceptual/ManPages_iPhoneOS/man3/CCryptorCreateFromData.3cc.html
    // For block ciphers, the output size will always be less than or equal to the input size plus the size of one block.
    size_t buffSize = dataLength + kCCBlockSizeAES128;
    void *buff = malloc(buffSize);
    
    size_t numBytesEncrypted = 0;
    //refer to http://www.opensource.apple.com/source/CommonCrypto/CommonCrypto-36064/CommonCrypto/CommonCryptor.h
    //for details on this function
    //Stateless, one-shot encrypt or decrypt operation.
    CCCryptorStatus status = CCCrypt(kCCEncrypt, /* kCCEncrypt, etc. */
                                     kCCAlgorithmAES128, /* kCCAlgorithmAES128, etc. */
                                     kCCOptionPKCS7Padding, /* kCCOptionPKCS7Padding, etc. */
                                     keyPointer, kCCKeySizeAES256, /* key and its length */
                                     ivPointer, /* initialization vector - use random IV everytime */
                                     [plainText bytes], [plainText length], /* input  */
                                     buff, buffSize,/* data RETURNED here */
                                     &numBytesEncrypted);
    if (status == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buff length:numBytesEncrypted];
    }
    
    free(buff);
    return nil;
}


-(NSData *)decrypt:(NSData *)encryptedText key:(NSString *)key iv:(NSString *)iv {
    char keyPointer[kCCKeySizeAES256+2],// room for terminator (unused) ref: https://devforums.apple.com/message/876053#876053
    ivPointer[kCCBlockSizeAES128+2];
    BOOL patchNeeded;
  
    patchNeeded = ([key length] > kCCKeySizeAES256+1);
    if(patchNeeded)
    {
        NSLog(@"Key length is longer %lu", (unsigned long)[[[StringEncryption alloc] md5:key] length]);
        key = [key substringToIndex:kCCKeySizeAES256]; // Ensure that the key isn't longer than what's needed (kCCKeySizeAES256)
    }

    [key getCString:keyPointer maxLength:sizeof(keyPointer) encoding:NSUTF8StringEncoding];
    [iv getCString:ivPointer maxLength:sizeof(ivPointer) encoding:NSUTF8StringEncoding];

    if (patchNeeded) {
        keyPointer[0] = '\0';  // Previous iOS version than iOS7 set the first char to '\0' if the key was longer than kCCKeySizeAES256
    }
    
    NSUInteger dataLength = [encryptedText length];
    
    //see https://developer.apple.com/library/ios/documentation/System/Conceptual/ManPages_iPhoneOS/man3/CCryptorCreateFromData.3cc.html
    // For block ciphers, the output size will always be less than or equal to the input size plus the size of one block.
    size_t buffSize = dataLength + kCCBlockSizeAES128;
    
    void *buff = malloc(buffSize);
    
    size_t numBytesEncrypted = 0;
    //refer to http://www.opensource.apple.com/source/CommonCrypto/CommonCrypto-36064/CommonCrypto/CommonCryptor.h
    //for details on this function
    //Stateless, one-shot encrypt or decrypt operation.
    CCCryptorStatus status = CCCrypt(kCCDecrypt,/* kCCEncrypt, etc. */
                                     kCCAlgorithmAES128, /* kCCAlgorithmAES128, etc. */
                                     kCCOptionPKCS7Padding, /* kCCOptionPKCS7Padding, etc. */
                                     keyPointer, kCCKeySizeAES256,/* key and its length */
                                     ivPointer, /* initialization vector - use same IV which was used for decryption */
                                     [encryptedText bytes], [encryptedText length], //input
                                     buff, buffSize,//output
                                     &numBytesEncrypted);
    if (status == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buff length:numBytesEncrypted];
    }
    
    free(buff);
    return nil;
}

//this function is no longer used in encryption / decryption
- (NSString *) md5:(NSString *) input
{
    const char *cStr = [input UTF8String];
    unsigned char digest[16];
    CC_MD5( cStr, strlen(cStr), digest ); // This is the md5 call
    
    NSMutableString *output = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];
    
    for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)
        [output appendFormat:@"%02x", digest[i]];
    
    return  output;
    
}

//function to generate random string of given length. 
//random strings are used as IV
- (NSData *)generateRandomIV:(size_t)length
{
    NSMutableData *data = [NSMutableData dataWithLength:length];
    
    int output = SecRandomCopyBytes(kSecRandomDefault,
                                    length,
                                    data.mutableBytes);
    NSAssert(output == 0, @"error generating random bytes: %d",
             errno);
    
    return data;
}

    /**
	 * This function computes the SHA256 hash of input string
	 * @param text input text whose SHA256 hash has to be computed
	 * @param length length of the text to be returned
	 * @return returns SHA256 hash of input text 
	 */
- (NSString*) sha256:(NSString *)key length:(NSInteger) length{
    const char *s=[key cStringUsingEncoding:NSASCIIStringEncoding];
    NSData *keyData=[NSData dataWithBytes:s length:strlen(s)];
    
    uint8_t digest[CC_SHA256_DIGEST_LENGTH]={0};
    CC_SHA256(keyData.bytes, keyData.length, digest);
    NSData *out=[NSData dataWithBytes:digest length:CC_SHA256_DIGEST_LENGTH];
    NSString *hash=[out description];
    hash = [hash stringByReplacingOccurrencesOfString:@" " withString:@""];
    hash = [hash stringByReplacingOccurrencesOfString:@"<" withString:@""];
    hash = [hash stringByReplacingOccurrencesOfString:@">" withString:@""];
    
    if(length > [hash length])
    {
        return  hash;
    }
    else
    {
        return [hash substringToIndex:length];
    }
 }

@end


================================================
FILE: iOS/NSData+Base64.h
================================================
//
//  NSData+Base64.h
//  base64
//
//  Created by Matt Gallagher on 2009/06/03.
//  Copyright 2009 Matt Gallagher. All rights reserved.
//
//  This software is provided 'as-is', without any express or implied
//  warranty. In no event will the authors be held liable for any damages
//  arising from the use of this software. Permission is granted to anyone to
//  use this software for any purpose, including commercial applications, and to
//  alter it and redistribute it freely, subject to the following restrictions:
//
//  1. The origin of this software must not be misrepresented; you must not
//     claim that you wrote the original software. If you use this software
//     in a product, an acknowledgment in the product documentation would be
//     appreciated but is not required.
//  2. Altered source versions must be plainly marked as such, and must not be
//     misrepresented as being the original software.
//  3. This notice may not be removed or altered from any source
//     distribution.
//

#import <Foundation/Foundation.h>

void *NewBase64Decode(
	const char *inputBuffer,
	size_t length,
	size_t *outputLength);

char *NewBase64Encode(
	const void *inputBuffer,
	size_t length,
	bool separateLines,
	size_t *outputLength);

@interface NSData (Base64)

+ (NSData *)dataFromBase64String:(NSString *)aString;
- (NSString *)base64EncodedString;

// added by Hiroshi Hashiguchi
- (NSString *)base64EncodedStringWithSeparateLines:(BOOL)separateLines;

@end

================================================
FILE: iOS/NSData+Base64.m
================================================
//
//  NSData+Base64.m
//
// Derived from http://colloquy.info/project/browser/trunk/NSDataAdditions.h?rev=1576
// Created by khammond on Mon Oct 29 2001.
// Formatted by Timothy Hatcher on Sun Jul 4 2004.
// Copyright (c) 2001 Kyle Hammond. All rights reserved.
// Original development by Dave Winer.
//

#import "NSData+Base64.h"

#import <Foundation/Foundation.h>

static char encodingTable[64] = {
		'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
		'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
		'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
		'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/' };

@implementation NSData (Base64)

+ (NSData *) dataWithBase64EncodedString:(NSString *) string {
	NSData *result = [[NSData alloc] initWithBase64EncodedString:string];
	return [result autorelease];
}

- (id) initWithBase64EncodedString:(NSString *) string {
	NSMutableData *mutableData = nil;

	if( string ) {
		unsigned long ixtext = 0;
		unsigned long lentext = 0;
		unsigned char ch = 0;
		unsigned char inbuf[3], outbuf[4];
		short i = 0, ixinbuf = 0;
		BOOL flignore = NO;
		BOOL flendtext = NO;
		NSData *base64Data = nil;
		const unsigned char *base64Bytes = nil;

		// Convert the string to ASCII data.
		base64Data = [string dataUsingEncoding:NSASCIIStringEncoding];
		base64Bytes = [base64Data bytes];
		mutableData = [NSMutableData dataWithCapacity:[base64Data length]];
		lentext = [base64Data length];

		while( YES ) {
			if( ixtext >= lentext ) break;
			ch = base64Bytes[ixtext++];
			flignore = NO;

			if( ( ch >= 'A' ) && ( ch <= 'Z' ) ) ch = ch - 'A';
			else if( ( ch >= 'a' ) && ( ch <= 'z' ) ) ch = ch - 'a' + 26;
			else if( ( ch >= '0' ) && ( ch <= '9' ) ) ch = ch - '0' + 52;
			else if( ch == '+' ) ch = 62;
			else if( ch == '=' ) flendtext = YES;
			else if( ch == '/' ) ch = 63;
			else flignore = YES; 
   
			if( ! flignore ) {
				short ctcharsinbuf = 3;
				BOOL flbreak = NO;

				if( flendtext ) {
					if( ! ixinbuf ) break;
					if( ( ixinbuf == 1 ) || ( ixinbuf == 2 ) ) ctcharsinbuf = 1;
					else ctcharsinbuf = 2;
					ixinbuf = 3;
					flbreak = YES;
				}

				inbuf [ixinbuf++] = ch;

				if( ixinbuf == 4 ) {
					ixinbuf = 0;
					outbuf [0] = ( inbuf[0] << 2 ) | ( ( inbuf[1] & 0x30) >> 4 );
					outbuf [1] = ( ( inbuf[1] & 0x0F ) << 4 ) | ( ( inbuf[2] & 0x3C ) >> 2 );
					outbuf [2] = ( ( inbuf[2] & 0x03 ) << 6 ) | ( inbuf[3] & 0x3F );

					for( i = 0; i < ctcharsinbuf; i++ ) 
						[mutableData appendBytes:&outbuf[i] length:1];
				}

				if( flbreak )  break;
			}
		}
	}

	self = [self initWithData:mutableData];
	return self;
}

- (NSString *) base64EncodingWithLineLength:(unsigned int) lineLength {
	const unsigned char	*bytes = [self bytes];
	NSMutableString *result = [NSMutableString stringWithCapacity:[self length]];
	unsigned long ixtext = 0;
	unsigned long lentext = [self length];
	long ctremaining = 0;
	unsigned char inbuf[3], outbuf[4];
	short i = 0;
	short charsonline = 0, ctcopy = 0;
	unsigned long ix = 0;

	while( YES ) {
		ctremaining = lentext - ixtext;
		if( ctremaining <= 0 ) break;

		for( i = 0; i < 3; i++ ) {
			ix = ixtext + i;
			if( ix < lentext ) inbuf[i] = bytes[ix];
			else inbuf [i] = 0;
		}

		outbuf [0] = (inbuf [0] & 0xFC) >> 2;
		outbuf [1] = ((inbuf [0] & 0x03) << 4) | ((inbuf [1] & 0xF0) >> 4);
		outbuf [2] = ((inbuf [1] & 0x0F) << 2) | ((inbuf [2] & 0xC0) >> 6);
		outbuf [3] = inbuf [2] & 0x3F;
		ctcopy = 4;

		switch( ctremaining ) {
		case 1: 
			ctcopy = 2; 
			break;
		case 2: 
			ctcopy = 3; 
			break;
		}

		for( i = 0; i < ctcopy; i++ )
			[result appendFormat:@"%c", encodingTable[outbuf[i]]];

		for( i = ctcopy; i < 4; i++ )
			[result appendFormat:@"%c",'='];

		ixtext += 3;
		charsonline += 4;

		if( lineLength > 0 ) {
			if (charsonline >= lineLength) {
				charsonline = 0;
				[result appendString:@"\n"];
			}
		}
	}

	return result;
}

@end