C# Sample to DSC Sign AspID + TimeStamp
The below method and other Cryptographic methods are available in
FREE library TaxProGST.API in TPCrypto class
//Sign String with Digital Signature
// PfxFile (full .pfx file path) may also be replaced with byte[] of pfxfile
/// <returns>Digital Signature Hash</returns>
public static string DSCSignForSession(string ContentToSign, string PfxFile, string DSCPassword)
{
try
{
X509Store store = new X509Store(StoreLocation.CurrentUser);
store.Open(new OpenFlags());
X509Certificate2 AspCert = null;
X509Certificate2Collection certificates = new X509Certificate2Collection();
if (File.Exists(PfxFile))
certificates.Import(PfxFile, DSCPassword, X509KeyStorageFlags.PersistKeySet);
if (certificates.Count == 0)
return "Certificate not found";
foreach (X509Certificate2 cert in certificates)
{
foreach (string cerProp in cert.Subject.Split(','))
{
if(cerProp.Trim().StartsWith("OU") && cerProp.Split('=')[1].ToUpper().Contains("GST"))
{
AspCert = cert;
break;
}
}
}
if (AspCert != null)
{
RSACryptoServiceProvider rsaEncryptor = (RSACryptoServiceProvider)AspCert.PrivateKey;
byte[] CalcHash = (new SHA256Managed().ComputeHash(Encoding.UTF8.GetBytes(ContentToSign)));
return (Convert.ToBase64String(rsaEncryptor.SignHash(CalcHash, CryptoConfig.MapNameToOID("SHA256"))));
}
else
return "Certificate not found";
}
catch(Exception ex)
{
return ex.Message;
}
}
