Refactoring

Author: lokeshgupta1981

src/com/howtodoinjava/core/security/AES256.java

@@ -0,0 +1,55 @@
+package com.howtodoinjava.core.security;
+
+import javax.crypto.Cipher;
+import javax.crypto.SecretKey;
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.PBEKeySpec;
+import javax.crypto.spec.SecretKeySpec;
+import java.nio.charset.StandardCharsets;
+import java.security.spec.KeySpec;
+import java.util.Base64;
+
+public class AES256 {
+  private static final String SECRET_KEY = "my_super_secret_key_ho_ho_ho";
+  private static final String SALT = "ssshhhhhhhhhhh!!!!";
+
+  public static String encrypt(String strToEncrypt) {
+    try {
+      byte[] iv = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+      IvParameterSpec ivspec = new IvParameterSpec(iv);
+
+      SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
+      KeySpec spec = new PBEKeySpec(SECRET_KEY.toCharArray(), SALT.getBytes(), 65536, 256);
+      SecretKey tmp = factory.generateSecret(spec);
+      SecretKeySpec secretKey = new SecretKeySpec(tmp.getEncoded(), "AES");
+
+      Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+      cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivspec);
+      return Base64.getEncoder()
+          .encodeToString(cipher.doFinal(strToEncrypt.getBytes(StandardCharsets.UTF_8)));
+    } catch (Exception e) {
+      System.out.println("Error while encrypting: " + e.toString());
+    }
+    return null;
+  }
+
+  public static String decrypt(String strToDecrypt) {
+    try {
+      byte[] iv = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+      IvParameterSpec ivspec = new IvParameterSpec(iv);
+
+      SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
+      KeySpec spec = new PBEKeySpec(SECRET_KEY.toCharArray(), SALT.getBytes(), 65536, 256);
+      SecretKey tmp = factory.generateSecret(spec);
+      SecretKeySpec secretKey = new SecretKeySpec(tmp.getEncoded(), "AES");
+
+      Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
+      cipher.init(Cipher.DECRYPT_MODE, secretKey, ivspec);
+      return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));
+    } catch (Exception e) {
+      System.out.println("Error while decrypting: " + e.toString());
+    }
+    return null;
+  }
+}

src/com/howtodoinjava/core/security/AES256Example.java

@@ -0,0 +1,14 @@
+package com.howtodoinjava.core.security;
+
+public class AES256Example {
+  public static void main(String[] args) {
+    String originalString = "howtodoinjava.com";
+
+    String encryptedString = AES256.encrypt(originalString);
+    String decryptedString = AES256.decrypt(encryptedString);
+
+    System.out.println(originalString);
+    System.out.println(encryptedString);
+    System.out.println(decryptedString);
+  }
+}