package myLib;
import java.io.UnsupportedEncodingException;
import java.security.GeneralSecurityException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;
import org.apache.xml.security.exceptions.Base64DecodingException;
/**
*
* @author Mohit Kumar Gupta
*/
public class CryptoAES256 {
public static void main(String[] args) {
try {
String passP = "Bar12345Barjhggfh12345"; // 128 bit key
String encryptedString = encrypt(passP, "Hello Mohit");
System.out.println("EncryptedString= " + encryptedString);
String decryptedString = decrypt(passP, encryptedString);
System.out.println("DecryptedString= " + decryptedString);
// System.out.println(decrypt(key, initVector,
// encrypt(key, initVector, "Hello World")));
String passPhase = "Bar1234";
String value = "Hello Mohit 1 2 3 4 5 6";
String enc = encrypt(passPhase, value);
String dec = decrypt(passPhase, enc);
System.out.println(enc);
System.out.println(dec);
} catch (Exception e) {
e.printStackTrace();
}
}
private static SecretKeySpec getKeySpec(String passphrase) throws NoSuchAlgorithmException, UnsupportedEncodingException {
MessageDigest digest = MessageDigest.getInstance("SHA-256");
return new SecretKeySpec(digest.digest(passphrase.getBytes("UTF-8")), "AES");
}
private static Cipher getCipher() throws NoSuchPaddingException, NoSuchAlgorithmException {
return Cipher.getInstance("AES/CBC/PKCS5PADDING");
}
public static String encrypt(String passphrase, String value) throws GeneralSecurityException, UnsupportedEncodingException {
byte[] initVector = new byte[16];
SecureRandom.getInstanceStrong().nextBytes(initVector);
Cipher cipher = getCipher();
cipher.init(Cipher.ENCRYPT_MODE, getKeySpec(passphrase), new IvParameterSpec(initVector));
byte[] encrypted = cipher.doFinal(value.getBytes());
return DatatypeConverter.printBase64Binary(initVector)
+ DatatypeConverter.printBase64Binary(encrypted);
}
public static String decrypt(String passphrase, String encrypted) throws GeneralSecurityException, UnsupportedEncodingException, Base64DecodingException {
byte[] initVector = DatatypeConverter.parseBase64Binary(encrypted.substring(0, 24));
Cipher cipher = getCipher();
cipher.init(Cipher.DECRYPT_MODE, getKeySpec(passphrase), new IvParameterSpec(initVector));
byte[] original = cipher.doFinal(DatatypeConverter.parseBase64Binary(encrypted.substring(24)));
return new String(original);
}
}
