Encryption Bean

SymmetricEncryption.java

package com.thehutgroup.thirdpartyplatform.service;

public interface SymmetricEncryption {
	
	public String encrypt(String plainText, String salt);
	public String encrypt(String plainText, int salt);
	
	public String decrypt(String encryptedText, String salt);
	public String decrypt(String encryptedText, int salt);

}

SymmetricEncryptionImpl.java

package com.thehutgroup.thirdpartyplatform.service.impl;

import java.security.Key;
import java.security.MessageDigest;
import java.util.Arrays;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import com.thehutgroup.thirdpartyplatform.service.SymmetricEncryption;

@Component
public class SymmetricEncryptionImpl implements SymmetricEncryption {
	
	@Value("${encryption.key}")
	String encryptionKey;
	
	private static final String ALG = "AES";
	
	@Override
	public String encrypt(String plainText, String salt) {
		try {
			Key key = generateKey(salt);
			Cipher c = Cipher.getInstance(ALG);
			c.init(Cipher.ENCRYPT_MODE, key);

			byte[] encrypted = c.doFinal(plainText.getBytes());
			String b64encrypted = DatatypeConverter.printBase64Binary(encrypted);
			return b64encrypted;
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	@Override
	public String decrypt(String encryptedText, String salt) {
		try {
			Key key = generateKey(salt);
			Cipher c = Cipher.getInstance(ALG);
			c.init(Cipher.DECRYPT_MODE, key);
			byte[] b64encrypted = DatatypeConverter.parseBase64Binary(encryptedText);
			
			byte[] unencrypted = c.doFinal(b64encrypted);
			String saltedPlaintext = new String(unencrypted);
			return saltedPlaintext;
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}
	
	private Key generateKey(String salt) throws Exception {
		MessageDigest md = MessageDigest.getInstance("SHA-1");
		byte[] hash = md.digest((encryptionKey + salt).getBytes("UTF-8"));
		byte[] key = Arrays.copyOf(hash, 16);
		
		return new SecretKeySpec(key, ALG);
	}

	@Override
	public String encrypt(String plainText, int salt) {
		return encrypt(plainText, Integer.toString(salt));
	}

	@Override
	public String decrypt(String encryptedText, int salt) {
		return decrypt(encryptedText, Integer.toString(salt));
	}

}