private void AuthenticateToken(Guid id, string token, string timeStamp)
{
var validToken = string.Join(":", id.ToString(), "MANIFEST_SSO_SALT", timeStamp);
var hash = validToken.ToHash<SHA1Managed>();
if (token != hash)
{
throw new HttpException(403, "Authentication failed");
}
var validTime = (DateTime.UtcNow.AddMinutes(-5) - new DateTime(1970, 1, 1)).TotalSeconds;
if (Convert.ToInt32(timeStamp) < validTime)
{
throw new HttpException(403, "Timestamp too old");
}
}