private static LicenseTerms ValidateLicense(LicenseDTO license)
{
RSACryptoServiceProvider rsa = GetPublicKeyFromAssemblyAtClient(Assembly.GetExecutingAssembly());
byte[] dataToVerify = Convert.FromBase64String(license.LicenseTerms);
byte[] signature = Convert.FromBase64String(license.Signature);
// verify that the license-terms match the signature data
if (rsa.VerifyData(dataToVerify, new SHA1CryptoServiceProvider(), signature))
{
return(LicenseTerms.FromString(license.LicenseTerms));
}
else
{
throw new Exception("license file is tempered.");
}
}
/// <summary>
/// validate license file and return the license terms.
/// </summary>
/// <param name="license"></param>
/// <param name="publicKey"></param>
/// <returns></returns>
internal static LicenseTerms GetValidTerms(License license, String publicKey)
{
// create the crypto-service provider:
DSACryptoServiceProvider dsa = new DSACryptoServiceProvider();
// setup the provider from the public key:
dsa.FromXmlString(publicKey);
// get the license terms data:
byte[] terms = Convert.FromBase64String(license.LicenseTerms);
// get the signature data:
byte[] signature = Convert.FromBase64String(license.Signature);
// verify that the license-terms match the signature data
if (dsa.VerifyData(terms, signature))
{
return(LicenseTerms.FromString(license.LicenseTerms));
}
else
{
throw new SecurityException("Signature Not Verified!");
}
}