Many people face problem while decrypting the encrypted data as the KEY used for encryption if stored as String in database then it becomes very tough to use that string as the KEY. So below is the code where you only need to store the encrypted code and not the key. The decryption will take place as an when wanted.
For encryption we must use a secret key along with an algorithm. In the following example we use an algorithm called AES 128 and the bytes of the word "TheBestSecretKey" as the secret key (the best secret key we found in this world). AES algorithm can use a key of 128 bits (16 bytes * 8); so we selected that key.
package nomad;
import java.security.*;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.*;
import sun.misc.*;
public class AESencrp {
private static final String ALGO = "AES";
private static final byte[] keyValue =
new byte[] { 'T', 'h', 'e', 'B', 'e', 's', 't',
'S', 'e', 'c', 'r','e', 't', 'K', 'e', 'y' };
public static String encrypt(String Data) throws Exception {
Key key = generateKey();
Cipher c = Cipher.getInstance(ALGO);
c.init(Cipher.ENCRYPT_MODE, key);
byte[] encVal = c.doFinal(Data.getBytes());
String encryptedValue = new BASE64Encoder().encode(encVal);
return encryptedValue;
}
public static String decrypt(String encryptedData) throws Exception {
Key key = generateKey();
Cipher c = Cipher.getInstance(ALGO);
c.init(Cipher.DECRYPT_MODE, key);
byte[] decordedValue = new BASE64Decoder().decodeBuffer(encryptedData);
byte[] decValue = c.doFinal(decordedValue);
String decryptedValue = new String(decValue);
return decryptedValue;
}
private static Key generateKey() throws Exception {
Key key = new SecretKeySpec(keyValue, ALGO);
return key;
}
}
We use "generateKey()" method to generate a secret key for AES algorithm with a given key.
Below is the code how you can use the above encryption algorithm.
package nomad;
public class Checker {
public static void main(String[] args) throws Exception {
String password = "mypassword";
String passwordEnc = AESencrp.encrypt(password);
String passwordDec = AESencrp.decrypt(passwordEnc);
System.out.println("Plain Text : " + password);
System.out.println("Encrypted Text : " + passwordEnc);
System.out.println("Decrypted Text : " + passwordDec);
}
}
