Here is one method..just try..
private static string Encrypt(string plainStr, string completeEncodedKey, int keySize)
{
RijndaelManaged aesEncryption = new RijndaelManaged();
aesEncryption.KeySize = keySize;
aesEncryption.BlockSize = 128;
aesEncryption.Mode = CipherMode.CBC;
aesEncryption.Padding = PaddingMode.PKCS7;
aesEncryption.IV = Convert.FromBase64String(Encoding.UTF8.GetString(Convert.FromBase64String(completeEncodedKey)).Split(',')[0]);
aesEncryption.Key = Convert.FromBase64String(Encoding.UTF8.GetString(Convert.FromBase64String(completeEncodedKey)).Split(',')[1]);
byte[] plainText = Encoding.UTF8.GetBytes(plainStr);
ICryptoTransform crypto = aesEncryption.CreateEncryptor();
byte[] cipherText = crypto.TransformFinalBlock(plainText, 0, plainText.Length);
return Convert.ToBase64String(cipherText);
}
private static string Decrypt(string encryptedText, string completeEncodedKey, int keySize)
{
RijndaelManaged aesEncryption = new RijndaelManaged();
aesEncryption.KeySize = keySize;
aesEncryption.BlockSize = 128;
aesEncryption.Mode = CipherMode.CBC;
aesEncryption.Padding = PaddingMode.PKCS7;
aesEncryption.IV = Convert.FromBase64String(Encoding.UTF8.GetString(Convert.FromBase64String(completeEncodedKey)).Split(',')[0]);
aesEncryption.Key = Convert.FromBase64String(Encoding.UTF8.GetString(Convert.FromBase64String(completeEncodedKey)).Split(',')[1]);
ICryptoTransform decrypto = aesEncryption.CreateDecryptor();
byte[] encryptedBytes = Convert.FromBase64CharArray(encryptedText.ToCharArray(), 0, encryptedText.Length);
return Encoding.UTF8.GetString(decrypto.TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length));
}