JAVA - AES Encryption and Decryption example - Symmetric cryptography

Advanced Encryption Standard which is a symmetric encryption algorithm. AES encryption is used by the U.S. to secure sensitive but unclassified material, so we can say it is secure enough.

Advanced Encryption Standard(AES) is a symmetric encryption algorithm. AES is the industry standard now as it allows 128-bit, 192-bit and 256-bit encryption. Symmetric encryption is very fast as compared to asymmetric encryption and is used in systems such as database systems.

The following illustration highlights how symmetric cryptography works:

Example:

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Arrays;
import java.util.Base64;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;
public class AESDemo {
    private static SecretKeySpec secretKey;
    private static byte[] key;
    public static void main(String[] args) 
           throws NoSuchAlgorithmException {
        // key
        String secretKey  = "your secret key";
              
        // secret text
        String originalString = "knowledgefactory.net";
       
        // Encryption
        String encryptedString = 
                       AESDemo.encrypt
                             (originalString, secretKey);
        // Decryption
        String decryptedString = 
                       AESDemo.decrypt
                             (encryptedString, secretKey);
      
        // OriginalString,encryptedString,decryptedString
        System.out.println("Original String:" + originalString);
        System.out.println("Encrypted value:" + encryptedString);
        System.out.println("Decrypted value:" + decryptedString);
    }
    // set key
    public static void setKey(String myKey) {
        MessageDigest sha = null;
        try {
            key = myKey.getBytes("UTF-8");
            sha = MessageDigest.getInstance("SHA-1");
            key = sha.digest(key);
            key = Arrays.copyOf(key, 16);
            secretKey = new SecretKeySpec(key, "AES");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
    }
    // method to encrypt the secret text using key
    public static String encrypt
              (String strToEncrypt, String secret) {
        try {
            setKey(secret);
            Cipher cipher = Cipher.
                     getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
            return Base64.getEncoder().
                     encodeToString(cipher.
                        doFinal(strToEncrypt.getBytes("UTF-8")));
        } catch (Exception e) {
            System.out.println("Error while encrypting: " + e);
        }
        return null;
    }
    
    // method to decrypt the secret text using key
    public static String decrypt(String strToDecrypt, String secret) {
        try {
            setKey(secret);
            Cipher cipher = Cipher.
                       getInstance("AES/ECB/PKCS5PADDING");
            cipher.init(Cipher.DECRYPT_MODE, secretKey);
            return new String(cipher.
                       doFinal(Base64.getDecoder().
                            decode(strToDecrypt)));
        } catch (Exception e) {
            System.out.println("Error while decrypting: " + e);
        }
        return null;
    }
}

Output:

Original String:knowledgefactory.net
Encrypted value:7W9JdoGEuWiV5EFdQxdyE+PYnj7WnkfeMhb3xU5uHgo=
Decrypted value:knowledgefactory.net

More...

• Hashing in Java - MD5 ,SHA-1, SHA-256, SHA-384,SHA-512 and PBKDF2

• Java-RSA Encryption and Decryption with example
  

• JAVA- AES Encryption and Decryption with example  
  

• Java - DES Encryption and Decryption with example 
  

• Java- Blowfish Encryption and decryption with Example 
  

Spring Boot + Angular - CRUD examples:

• Spring Boot + Angular 10 + Mongo DB CRUD Example

• Spring Boot - Angular JS - Bootstrap - JPA - CRUD

• Angular 10 + Kotlin +Spring Boot + Mongo DB CRUD

Spring Boot + React JS - CRUD examples:

• React JS + Spring Boot + MongoDB CRUD

• React JS + SpringBoot + RDBMS - CRUD Example

• Kotlin + Spring Boot + React JS + MongoDB CRUD

Spring Boot + Vue JS - CRUD examples:

• Vue.js + Spring Boot + MongoDB CRUD Application

• Spring Boot + Vue.js + PostgreSQL CRUD Example

• Kotlin +Spring Boot + Mongo DB + Vue.js CRUD

Spring Boot + Template Engine - CRUD examples:

• Spring + Groovy Templates CRUD Example

• Spring Boot + FreeMarker + JPA - CRUD example

• Spring Boot + Mustache + Spring Data JPA - CRUD Example

• Spring Boot + Thymeleaf + Spring Data JPA CRUD Example

• Kotlin-Spring Boot-Thymeleaf-JPA-CRUD application

• Kotlin + Spring + Groovy Templates CRUD Example

• Kotlin + Spring Boot + FreeMarker + JPA - CRUD example

• Kotlin + Spring Boot + Mustache + JPA - CRUD example

Spring Boot + Vaadin CRUD examples:

• Vaadin + Spring Boot + Spring Data JPA CRUD Example

• Vaadin + Kotlin CRUD example