public ActionResult Decrypt(string secret, string HMacToken)
{
string msg = string.Empty;
bool isValidQueryString = TamperProofQueryString.ValidateQueryString(secret, HMacToken, out msg);
if (isValidQueryString)
{
string plainText = "The Magic Words are Squeamish Ossifrage";
string response = "";
if (string.IsNullOrEmpty(secret))
{
response = "No secret? Sorry, bad request!";
ViewBag.DecryptedText = response;
HttpContext.Response.StatusCode = 400;
return(View());
}
try
{
byte[] encryptedBytes = CryptoHelper.ConvertHexStringToByteArray(secret);
response = AESCrypto.AES_DecryptToString(encryptedBytes);
if (plainText.Equals(response, StringComparison.OrdinalIgnoreCase))
{
//Valid padding and valid plain text
HttpContext.Response.StatusCode = 200;
}
else
{
//Valid padding, but incorrect format")
HttpContext.Response.StatusCode = 404;
}
}
catch (CryptographicException cex)
{
//Invalid padding (Exception message: "Padding is invalid and cannot be removed.")
HttpContext.Response.StatusCode = 403;
response = cex.Message;
}
ViewBag.DecryptedText = response;
return(View());
}
else
{
ViewBag.ErrorMessage = msg;
return(View("AccessDenied"));
}
}
public static string GenerateHMac(string cipherText)
{
string HMacToken = TamperProofQueryString.GetTamperProofToken(cipherText);
return(HMacToken);
}