After I got very helpful suggestions from @deathismyfriend and other, I found out what I am missing in my C# Decrypt function.So I change my function as below.
/// C# Error Fixed Version - CipherMode.ECB
public static string keyStr = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
private static string Encrypt(string PlainText)
{
RijndaelManaged aes = new RijndaelManaged();
aes.BlockSize = 128;
aes.KeySize = 256;
/// In Java, Same with below code
/// Cipher _Cipher = Cipher.getInstance("AES"); // Java Code
aes.Mode = CipherMode.ECB;
byte[] keyArr = Convert.FromBase64String(keyStr);
byte[] KeyArrBytes32Value = new byte[32];
Array.Copy(keyArr, KeyArrBytes32Value, 32);
aes.Key = KeyArrBytes32Value;
ICryptoTransform encrypto = aes.CreateEncryptor();
byte[] plainTextByte = ASCIIEncoding.UTF8.GetBytes(PlainText);
byte[] CipherText = encrypto.TransformFinalBlock(plainTextByte, 0, plainTextByte.Length);
return Convert.ToBase64String(CipherText);
}
private static string Decrypt(string CipherText)
{
RijndaelManaged aes = new RijndaelManaged();
aes.BlockSize = 128;
aes.KeySize = 256;
/// In Java, Same with below code
/// Cipher _Cipher = Cipher.getInstance("AES"); // Java Code
aes.Mode = CipherMode.ECB;
byte[] keyArr = Convert.FromBase64String(keyStr);
byte[] KeyArrBytes32Value = new byte[32];
Array.Copy(keyArr, KeyArrBytes32Value, 32);
aes.Key = KeyArrBytes32Value;
ICryptoTransform decrypto = aes.CreateDecryptor();
byte[] encryptedBytes = Convert.FromBase64CharArray(CipherText.ToCharArray(), 0, CipherText.Length);
byte[] decryptedData = decrypto.TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length);
return ASCIIEncoding.UTF8.GetString(decryptedData);
}
By using upper c# function , now I can decrypt and read cipher text.
Below is what I found out after I getting error again and again.
CryptographicException: Padding is invalid and cannot be removed.
Solution:
_RijndaelManaged.Padding = CipherMode.xxx; ///should toggle here
_RijndaelManaged.Padding = PaddingMode.xxx; ///should toggle here
CryptographicException: Length of the data to decrypt is invalid.
CryptographicException: Specified initialization vector (IV) does not match the block size for this algorithm.
Solution
1. _RijndaelManaged.BlockSize = 128; /// Must be
2. _RijndaelManaged.KeySize = 256; /// Must be
3. _RijndaelManaged.Key = Byte Array Size must be 32 in length ( more detail 32*8 = 256 KeySize )
4. _RijndaelManaged.IV = Byte Array Size must be 16 in length ( more detail 16*8 = 128 BlockSize)
But when it come to security reason, I think I should not use ECB mode.
According to
So I Modify it again in Java and C#.
// Java code - Cipher mode CBC version.
// CBC version need Initialization vector IV.
// Reference from https://stackoverflow.com/questions/6669181/why-does-my-aes-encryption-throws-an-invalidkeyexception/6669812#6669812
import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;
public class CryptoSecurity {
public static String key = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
public static byte[] key_Array = Base64.decodeBase64(key);
public static String encrypt(String strToEncrypt)
{
try
{
//Cipher _Cipher = Cipher.getInstance("AES");
//Cipher _Cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
Cipher _Cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
// Initialization vector.
// It could be any value or generated using a random number generator.
byte[] iv = { 1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1, 7, 7, 7, 7 };
IvParameterSpec ivspec = new IvParameterSpec(iv);
Key SecretKey = new SecretKeySpec(key_Array, "AES");
_Cipher.init(Cipher.ENCRYPT_MODE, SecretKey, ivspec);
return Base64.encodeBase64String(_Cipher.doFinal(strToEncrypt.getBytes()));
}
catch (Exception e)
{
System.out.println("[Exception]:"+e.getMessage());
}
return null;
}
public static String decrypt(String EncryptedMessage)
{
try
{
//Cipher _Cipher = Cipher.getInstance("AES");
//Cipher _Cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
Cipher _Cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
// Initialization vector.
// It could be any value or generated using a random number generator.
byte[] iv = { 1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1, 7, 7, 7, 7 };
IvParameterSpec ivspec = new IvParameterSpec(iv);
Key SecretKey = new SecretKeySpec(key_Array, "AES");
_Cipher.init(Cipher.DECRYPT_MODE, SecretKey, ivspec);
byte DecodedMessage[] = Base64.decodeBase64(EncryptedMessage);
return new String(_Cipher.doFinal(DecodedMessage));
}
catch (Exception e)
{
System.out.println("[Exception]:"+e.getMessage());
}
return null;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
StringBuilder sb = new StringBuilder();
sb.append("xml file string ...");
String outputOfEncrypt = encrypt(sb.toString());
System.out.println("[CryptoSecurity.outputOfEncrypt]:"+outputOfEncrypt);
String outputOfDecrypt = decrypt(outputOfEncrypt);
//String outputOfDecrypt = decrypt(sb.toString());
System.out.println("[CryptoSecurity.outputOfDecrypt]:"+outputOfDecrypt);
}
}
In C#, I modify it like below.
// C# Code, CipherMode.CBC
// CBC version need Initialization vector IV.
public static string keyStr = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
private static string Encrypt(string PlainText)
{
RijndaelManaged aes = new RijndaelManaged();
aes.BlockSize = 128;
aes.KeySize = 256;
// It is equal in java
/// Cipher _Cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
byte[] keyArr = Convert.FromBase64String(keyStr);
byte[] KeyArrBytes32Value = new byte[32];
Array.Copy(keyArr, KeyArrBytes32Value, 32);
// Initialization vector.
// It could be any value or generated using a random number generator.
byte[] ivArr = { 1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1, 7, 7, 7, 7 };
byte[] IVBytes16Value = new byte[16];
Array.Copy(ivArr, IVBytes16Value, 16);
aes.Key = KeyArrBytes32Value;
aes.IV = IVBytes16Value;
ICryptoTransform encrypto = aes.CreateEncryptor();
byte[] plainTextByte = ASCIIEncoding.UTF8.GetBytes(PlainText);
byte[] CipherText = encrypto.TransformFinalBlock(plainTextByte, 0, plainTextByte.Length);
return Convert.ToBase64String(CipherText);
}
private static string Decrypt(string CipherText)
{
RijndaelManaged aes = new RijndaelManaged();
aes.BlockSize = 128;
aes.KeySize = 256;
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
byte[] keyArr = Convert.FromBase64String(keyStr);
byte[] KeyArrBytes32Value = new byte[32];
Array.Copy(keyArr, KeyArrBytes32Value, 32);
// Initialization vector.
// It could be any value or generated using a random number generator.
byte[] ivArr = { 1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1, 7, 7, 7, 7 };
byte[] IVBytes16Value = new byte[16];
Array.Copy(ivArr, IVBytes16Value, 16);
aes.Key = KeyArrBytes32Value;
aes.IV = IVBytes16Value;
ICryptoTransform decrypto = aes.CreateDecryptor();
byte[] encryptedBytes = Convert.FromBase64CharArray(CipherText.ToCharArray(), 0, CipherText.Length);
byte[] decryptedData = decrypto.TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length);
return ASCIIEncoding.UTF8.GetString(decryptedData);
}
Now it all work.
For more detail about AES, click this link which I was given by @deathismyfriend.
It is also very useful.