private string CalculateChecksumFromPostback(PostbackTransaction postback)
{
using (var sha1 = SHA1.Create()) {
var checksumBytes = sha1.ComputeHash(Encoding.UTF8.GetBytes(
$"{postback.Id}||{(int)postback.Status}|{settings.SharedSecret}"));
return(BitConverter.ToString(checksumBytes)
.Replace("-", string.Empty)
.ToLower());
}
}
private string GetChecksumFromHeadersOrPostback(
IDictionary <string, string[]> headers,
PostbackTransaction postback)
{
string[] postbackChecksumArray;
if (headers.TryGetValue("Checksum", out postbackChecksumArray))
{
return(postbackChecksumArray.First());
}
else
{
return(postback.Checksum);
}
}
private bool HasValidChecksumProperties(string postbackChecksum, PostbackTransaction postback)
{
return(!string.IsNullOrWhiteSpace(postbackChecksum) && !string.IsNullOrWhiteSpace(postback.Id));
}
