/// <summary>
/// Checks if the license key file has been modified by an unauthorized person.
/// This method will only return true if the license key information is exactly
/// the same as the one that was provided and signed by SKM.
/// </summary>
/// <param name="rsaPublicKey"></param>
/// <returns>Returns true if the signature is valid. False otherwise.</returns>
private static bool IsLicenceseKeyGenuine(this LicenseKey licenseKey, string rsaPublicKey)
{
if (licenseKey?.Signature != "")
{
var prevSignature = licenseKey.Signature;
try
{
licenseKey.Signature = "";
var rawResult = licenseKey.AsDictionary();
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(2048);
rsa.FromXmlString(rsaPublicKey);
byte[] signature = Convert.FromBase64String(prevSignature);
// the signature should not be included into the signature :)
System.Diagnostics.Debug.WriteLine(String.Join(",", rawResult.Select(x => x.Value)));
return(rsa.VerifyData(HelperMethods.GetBytes(String.Join(",", rawResult.Select(x => x.Value))), "SHA256", signature));
}
catch { }
finally
{
licenseKey.Signature = prevSignature;
}
}
return(false);
}
/// <summary>
/// Checks if the license key file has been modified by an unauthorized person.
/// This method will only return true if the license key information is exactly
/// the same as the one that was provided and signed by SKM.
/// </summary>
/// <param name="rsaPublicKey"></param>
/// <returns>Returns true if the signature is valid. False otherwise.</returns>
private static bool IsLicenceseKeyGenuine(this LicenseKey licenseKey, string rsaPublicKey)
{
if (licenseKey?.RawResponse != null)
{
var license = LicenseKey.FromResponse(rsaPublicKey, licenseKey.RawResponse);
if (license == null)
{
return(false);
}
return(license.Equals(licenseKey));
}
if (licenseKey?.Signature != "")
{
var prevSignature = licenseKey.Signature;
try
{
licenseKey.Signature = "";
var rawResult = licenseKey.AsDictionary();
#if NET40 || NET46 || NET35 || NET47 || NET471 || NET45
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(2048);
rsa.FromXmlString(rsaPublicKey);
#else
RSA rsa = RSA.Create();
rsa.ImportParameters(SecurityMethods.FromXMLString(rsaPublicKey));
#endif
byte[] signature = Convert.FromBase64String(prevSignature);
// the signature should not be included into the signature :)
#if NET40 || NET46 || NET35 || NET47 || NET471 || NET45
return(rsa.VerifyData(HelperMethods.GetBytes(String.Join(",", rawResult.Where(x => x.Key != "RawResponse").Select(x => x.Value).ToArray())), "SHA256", signature));
#else
return(rsa.VerifyData(HelperMethods.GetBytes(String.Join(",", rawResult.Where(x => x.Key != "RawResponse").Select(x => x.Value))), signature, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1));
#endif
}
catch { }
finally
{
licenseKey.Signature = prevSignature;
}
}
return(false);
}