Java Encryption/ Decryption with AES Cipher. Compatible with cross platform C# Rijndael Cipher.

AES.java

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class AES  {

	/** Cipher for encryption **/
	Cipher ecipher;
	
	/** Cipher for decryption **/
	Cipher dcipher;

	/** Buffer used to transport the bytes from one stream to another **/
	byte[] buf = new byte[1024];	

	public AES(String strkey) throws UnsupportedEncodingException {
		
		byte[] keyBytes = new byte[16];
		byte[] iv = new byte[16];
		
		keyBytes = strkey.getBytes("UTF-8");
		Key key = new SecretKeySpec(keyBytes, "AES");
		iv = strkey.getBytes("UTF-8");
		
		AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
		try {
			ecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
			dcipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

			/** CBC requires an initialization vector **/
			ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
			dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	
	public void encrypt(InputStream in, OutputStream out) {
		try {
			
			out = new CipherOutputStream(out, ecipher);

			int numRead = 0;
			while ((numRead = in.read(buf)) >= 0) {
				out.write(buf, 0, numRead);
			}
			out.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public void decrypt(InputStream in, OutputStream out) {
		try {		
			
			buf = new byte[1024];			
			in = new CipherInputStream(in, dcipher);			
			
			int numRead = 0;			
			while ((numRead = in.read(buf)) >= 0) {
				out.write(buf, 0, numRead);
			}
			out.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	


	public static void main(String[] args) throws NoSuchAlgorithmException,
			FileNotFoundException, UnsupportedEncodingException {

    		String ENCRYPT_IN = "C:/path/to/file/data.csv";
		String ENCRYPT_OUT = "C:/path/to/file/data_encrypted.csv";
		
		String DECRYPT_IN = "C:/path/to/file/data_encrypted.csv";
		String DECRYPT_OUT = "C:/path/to/file/data_decrypted.csv";
		
		String KEY = "SecretKey1234567";	// Has to be 16/24/32 char(byte) long	
		
		AES test = new AES(KEY);
		
		test.encrypt(new FileInputStream(ENCRYPT_IN), new FileOutputStream(ENCRYPT_OUT));
		System.out.println("Encrypted..");
		
		test.decrypt(new FileInputStream(DECRYPT_IN), new FileOutputStream(DECRYPT_OUT));
		System.out.println("Decrypted..");
		
	}
}