public bool TryDecode(string code, out ProductLicense license)
{
// License format:
// No. Bytes Field Byte index
// 1 X 0
// 1 License flags 1
// 1 VersionNoApplicable 2
// 2 ExpirationDate 3
// 1 Y 5
// 1 ExpirationDays 6
// 1 ExpirationLoads 7
// 1 MaxSimultaneousUsers 8
// 1 Z 9
// X = random(0,255)
// Y = (byte[1] + byte[2] + byte[3] + byte[6] + byte[7] + byte[8]) % 255
// Z = (X^2 + Y^2) % 255
license = new ProductLicense();
if (string.IsNullOrEmpty(code))
{
return(false);
}
byte[] bytes = Base32Converter.FromBase32String(code.Replace("-", string.Empty));
if (bytes.Length != 10)
{
return(false);
}
bytes = bytes.Xor(ProductInformationServices.ProductInformation.ProductCode.ToByteArray());
// apply internal mask
StandardLicenseCodecTools.ApplyInternalMask(bytes);
int X = (int)bytes[0];
int Y = (int)bytes[5];
int Z = (int)bytes[9];
if (Y != (((int)bytes[1]) + ((int)bytes[2]) + ((int)bytes[3]) + ((int)bytes[6]) + ((int)bytes[7]) + ((int)bytes[8])) % 255)
{
return(false);
}
if ((X * X + Y * Y) % 255 != Z)
{
return(false);
}
license.Flags = (ProductLicenseFlags)bytes[1];
license.MajorVersionApplicable = bytes[2];
license.ExpirationDate = StandardLicenseCodecTools.FromDaysSince2008Jan1(BitConverter.ToUInt16(bytes, 3));
license.ExpirationDays = bytes[6];
license.ExpirationLoads = bytes[7];
license.MaxSimultaneousUsers = bytes[8];
return(true);
}
public static byte[] FromBase32(string text)
{
return(Base32Converter.FromBase32String(text));
}