[Java] How to encrypt with AES encryption with standard library

Thing you want to do

--I want to encrypt and save token using Java standard library --When you get token information, you want to use it in a decrypted state. --I want to use AES encryption with the same key for encryption and decryption.

Sample encryption / decryption process

--The key used for encryption & decryption is 128bit (= 16byte / 16 alphanumeric characters) --If the cipher mode is CBC, an initial vector with the same length as the key is required.

Implementation example

CryptSample.java

package com.tamorieeeen.sample

import java.util.Base64;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 *encryption/Decryption processing sample
 * @author tamorieeeen
 */
public class CryptSample {

  //algorithm/Block mode/Padding method
  private static final String ALGORITHM = "AES/CBC/PKCS5Padding";
  //Key used for encryption & decryption
  private static final String ENCRYPT_KEY = "yourEncryptKey01";
  //Initialization vector
  private static final String INIT_VECTOR = "yourInitVector01";

  private final IvParameterSpec iv = new IvParameterSpec(INIT_VECTOR.getBytes());
  private final SecretKeySpec key = new SecretKeySpec(ENCRYPT_KEY.getBytes(), "AES");

  /**
   *Save token
   */
  public void saveToken(String token) {

    String encryptedToken = this.encryptToken(token);
    //Save encryptedToken in DB
    this.saveTokenToDb(encryptedToken);
  }

  /**
   *Encryption process
   */
  private String encryptToken(String token) throws Exception {

    Cipher encrypter = Cipher.getInstance(ALGORITHM);
    encrypter.init(Cipher.ENCRYPT_MODE, this.key, this.iv);
    byte[] byteToken = encrypter.doFinal(token.getBytes());

    return new String(Base64.getEncoder().encode(byteToken));
  }

  /**
   *Get token
   */
  public String getToken() {

    //Get token from DB
    String encryptedToken = this.getEncryptedTokenFromDb();

    return this.decryptToken(encryptedToken);
  }

  /**
   *Decryption process
   */
  private String decryptToken(String encryptedToken) throws Exception {

    Cipher decrypter = Cipher.getInstance(ALGORITHM);
    decrypter.init(Cipher.DECRYPT_MODE, this.key, this.iv);
    byte[] byteToken = Base64.getDecoder().decode(encryptedToken);

    return new String(decrypter.doFinal(byteToken));
  }

  /**From here on down, create the methods you need**/

  /**
   *Save token in DB
   */
  private void saveTokenToDb(String encryptedToken) throws Exception {

    //Process to save encryptedToken in DB
  }

  /**
   *Get token from DB
   */
  private String getEncryptedTokenFromDb() throws Exception {

    //Process to get token from DB
  }
}

reference

[Java] Use cryptography with standard library Let's do cryptographic processing!