From 1e1b3fc927766be98ba4a1a3fdcae98f5df6aa89 Mon Sep 17 00:00:00 2001
From: Aniruddho Mitra <68218897+aniruddho-mitra@users.noreply.github.com>
Date: Wed, 5 Oct 2022 11:21:05 +0530
Subject: [PATCH] Create AES.java

---
 AES.java | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 AES.java

diff --git a/AES.java b/AES.java
new file mode 100644
index 0000000..2ac347f
--- /dev/null
+++ b/AES.java
@@ -0,0 +1,89 @@
+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.InvalidAlgorithmParameterException;  
+import java.security.InvalidKeyException;  
+import java.security.NoSuchAlgorithmException;  
+import java.security.spec.InvalidKeySpecException;  
+import java.security.spec.KeySpec;  
+import java.util.Base64;  
+import javax.crypto.BadPaddingException;  
+import javax.crypto.IllegalBlockSizeException;  
+import javax.crypto.NoSuchPaddingException;  
+public class AESExample   
+{  
+    /* Private variable declaration */  
+    private static final String SECRET_KEY = "123456789";  
+    private static final String SALTVALUE = "abcdefg";  
+   
+    /* Encryption Method */  
+    public static String encrypt(String strToEncrypt)   
+    {  
+    try   
+    {  
+      /* Declare a byte array. */  
+      byte[] iv = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};  
+      IvParameterSpec ivspec = new IvParameterSpec(iv);        
+      /* Create factory for secret keys. */  
+      SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");  
+      /* PBEKeySpec class implements KeySpec interface. */  
+      KeySpec spec = new PBEKeySpec(SECRET_KEY.toCharArray(), SALTVALUE.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);  
+      /* Retruns encrypted value. */  
+      return Base64.getEncoder()  
+.encodeToString(cipher.doFinal(strToEncrypt.getBytes(StandardCharsets.UTF_8)));  
+    }   
+    catch (InvalidAlgorithmParameterException | InvalidKeyException | NoSuchAlgorithmException | InvalidKeySpecException | BadPaddingException | IllegalBlockSizeException | NoSuchPaddingException e)   
+    {  
+      System.out.println("Error occured during encryption: " + e.toString());  
+    }  
+    return null;  
+    }  
+    
+    /* Decryption Method */  
+    public static String decrypt(String strToDecrypt)   
+    {  
+    try   
+    {  
+      /* Declare a byte array. */  
+      byte[] iv = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};  
+      IvParameterSpec ivspec = new IvParameterSpec(iv);  
+      /* Create factory for secret keys. */  
+      SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");  
+      /* PBEKeySpec class implements KeySpec interface. */  
+      KeySpec spec = new PBEKeySpec(SECRET_KEY.toCharArray(), SALTVALUE.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);  
+      /* Retruns decrypted value. */  
+      return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));  
+    }   
+    catch (InvalidAlgorithmParameterException | InvalidKeyException | NoSuchAlgorithmException | InvalidKeySpecException | BadPaddingException | IllegalBlockSizeException | NoSuchPaddingException e)   
+    {  
+      System.out.println("Error occured during decryption: " + e.toString());  
+    }  
+    return null;  
+    }  
+    /* Driver Code */  
+    public static void main(String[] args)   
+    {  
+        /* Message to be encrypted. */  
+        String originalval = "AES Encryption";  
+        /* Call the encrypt() method and store result of encryption. */  
+        String encryptedval = encrypt(originalval);  
+        /* Call the decrypt() method and store result of decryption. */  
+        String decryptedval = decrypt(encryptedval);  
+        /* Display the original message, encrypted message and decrypted message on the console. */  
+        System.out.println("Original value: " + originalval);  
+        System.out.println("Encrypted value: " + encryptedval);  
+        System.out.println("Decrypted value: " + decryptedval);  
+    }  
+}