import java.io.File;

	import java.io.FileInputStream;

	import java.io.FileOutputStream;

	import java.io.IOException;

	import java.io.InputStream;

	import java.io.OutputStream;

	import java.security.InvalidAlgorithmParameterException;

	import java.security.InvalidKeyException;

	import java.security.MessageDigest;

	import java.security.NoSuchAlgorithmException;

	import java.security.SecureRandom;

	

	import javax.crypto.Cipher;

	import javax.crypto.CipherOutputStream;

	import javax.crypto.NoSuchPaddingException;

	import javax.crypto.spec.IvParameterSpec;

	import javax.crypto.spec.SecretKeySpec;

	

	

	

	public class EncDecAESEncryptionExample {

	  private final static String KEYALG = "AES/CBC/PKCS5Padding";

	    

	  //encrypt method

	  public static boolean encrypt(String key, InputStream is, OutputStream out)

	    throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,

	    InvalidAlgorithmParameterException, IOException {

			

	      boolean enc = false;

	      int ivSize = 16;

	      int keySize = 32;

	      try {

	        //Generate IV

	        byte[] iv = new byte[ivSize];

	        SecureRandom random = new SecureRandom();

	        random.nextBytes(iv);

	        IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);

	

	        //Hash key

	        MessageDigest digest = MessageDigest.getInstance("SHA-256");

	        digest.update(key.getBytes());

	        byte[] keyBytes = new byte[keySize];

	        System.arraycopy(digest.digest(), 0, keyBytes, 0, keyBytes.length);

	        SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, "AES");

	        	

	        //write iv to file first

	        out.write(iv);

	

	        //Encrypt

	        Cipher c = Cipher.getInstance(KEYALG);

	        c.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);

		    	

	        out = new CipherOutputStream(out, c);

	        int count = 0;

	        byte[] buffer = new byte[1024];

	        while ((count = is.read(buffer)) >= 0) {

	          out.write(buffer, 0, count);

	        }

		    	

	        enc = true;

	      }

	      catch (Exception e) {

	        e.printStackTrace();

	        enc = false;

	      }

	      finally {

	        out.close();

	      }

		    

	      return enc;

	    }

	

	    //decrypt mode

	    public static boolean decrypt(String key, InputStream is, OutputStream out)

	      throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,

	      InvalidAlgorithmParameterException, IOException {

	    	

	      boolean dec = false;

	      int ivSize = 16;

	      int keySize = 32;

	    	

	      try {		

	        //Extract IV

	        byte[] iv = new byte[ivSize];

	        is.read(iv, 0, 16);

	        IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);

	    		

	        //Hash key

	        byte[] keyBytes = new byte[keySize];

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

	        md.update(key.getBytes());

	        System.arraycopy(md.digest(), 0, keyBytes, 0, keyBytes.length);

	        SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, "AES");

	    		

	        //Decrypt

	        Cipher c = Cipher.getInstance(KEYALG);

	        c.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);

	        out = new CipherOutputStream(out, c);

	        int count = 0;

	        byte[] buffer = new byte[1024];

	        while ((count = is.read(buffer)) >= 0) {

	          out.write(buffer, 0, count);

	        }

	

	        dec = true;

	      }

	      catch (Exception e) {

	        e.printStackTrace();

	        dec = false;

	      }

	      finally {

	        is.close();

	        out.close();

	      }    

	

	      return dec;

	    }

	

	

	    //process file for encryption or decryption

	    public static void main (String[] args) throws IOException {

	

	    //Files file mode 1, encrypt method

	    //Ex. "C:\test-original.docx"

	    File originalFile = new File("path\\to\\original\\file");

	    //Ex. "C:\my-hidden-file"

	    File encryptedOutFile = new File("your-fullpath\\new-encrypted-filename");

	

	    //Files for mode 2, decrypt method

	    //Ex. "C:\my-hidden-file" **encrypted file created in mode 1**

	    File encryptedInFile = new File("path\\to\\encrypted\\file");

	    //Ex. "C:\test-decrypted.docx"

	    File decrypted_file = 

	      new File("your-fullpath\\new-location-for-decrpyted-file-with-ext");

	    	

	    String passcode = "your encryption passcode 1";

	    //set encdec mode, 1 = encryption, 2 = decryption

	    int mode = 0;

	    boolean encDec = false;

	

	    try {           

	      //create 32 character, 

	      //encryption algorithm expects a passcode of base 16

	

	      if (mode == 1) {

	        //convert original file to inputstream

	        InputStream is = new FileInputStream(originalFile);

	        		

	        //call encrypt method

	        encDec = encrypt(passcode, is, 

	          new FileOutputStream(encryptedOutFile));

	

	        //create return values

	        if (encDec == true) {

	          System.out.println("File encrypted");

	        }

	        else {

	          System.out.println("File not encrypted");

	        }

	  

	      }

	      else if (mode == 2) {

	        //convert encrypted file to inputstream

	        InputStream is = new FileInputStream(encryptedInFile);

					    	          		       		  

	        //call decrypt method

	        encDec = decrypt(passcode, is, 

	          new FileOutputStream(decrypted_file));

	        if (encDec == true) {

	          System.out.println("File decrypted");	        		

	        }

	        else {

	          System.out.println("File not decrypted");

	        }

	      }

	      else {

	        System.out.println("Set mode to 1 or 2");

	      }

	    } 

	    catch (Exception e) {

	      e.printStackTrace();

	    }

	

	  }

	

	}