Basic Challenge Protocol - Win32 Programmer's Reference

Custom Search

Basic Challenge Protocol

The basic challenge protocol provides the means for an LSAPI-enabled application to verify that an LSAPI-compliant license system has given it legitimate permission to run.

Every license has one or more keys, called secrets, that the software publisher chooses. The publisher typically encrypts the secrets within the license and only the license server has the means to decrypt them. The basic challenge protocol supported by all LSAPI-compliant license systems works on the principle of shared secrets: the application and the license server share a secret value.

An LSAPI-compliant license system requires a minimum of four secrets, each 4 bytes (32 bits) in length. The application challenges the authenticity of a license by requiring the license system to prove that it has one of the secrets. The server can compute the correct response to the challenge only if it has the secret. It must return a mathematical function of the challenge plus the shared secret. Since the application also has the secrets on the license, it can compute the correct expected response to the challenge and check that the server's response was appropriate for the challenge. The secret itself never passes between the application and the license system in plain text.

The basic challenge protocol includes a level of mutual authentication to prove to the license system that the application has the selected secret. The protocol also helps ensure that an intruder cannot modify the parameters the application sends to the license system, or the parameters the license system returns to the application.

Additional information about the steps in the basic challenge protocol is provided in the following topics:

Last news from Greatis Software

    Nostalgia .Net     .Net is powerful, but not all-powerful, so sometimes we need to use Win32 API for our .Net applications. It's simple enough with Platform Invoke if you have Win32 skill, but we do not always have time to dig the ancient documentation, declare the special types that are compatible with Win32, find the values of the Win32's constants and so on. Nostalgia .Net offers several simple-to-use classes, and components that will allow you to forget about the headache of Win32 and just use the power of Win32 in your application the same way as you use the native. Net classes. More »

Recommended software for developers

    Ultimate Pack     Component pack for Delphi and C++ Builder that contains runtime form designer, runtime object inspector, print suite and much more for the very special price. More »

    Form Designer .Net     Unique runtime form design solution that allows to edit any form in .Net WinForms application at runtime with full source codes for only 300 euro! More »

    Print Suite .Net     Print Suite .Net is a set of components for easy printing texts, images and grids from your WinForms applications. Full C# source codes are available More »

    Gradient Controls .Net     Gradient Controls .Net offers controls with gradient background feature. Labels, panels and so on... Full C# source codes are available More »

    Greatis iGrid     iGrid plots drawing grid right over your desktop, so you can use it everywhere, with any drawing application without any special plugins for different graphic editors. More »

All the contacts and projects

Dmitry Vasiliev (just.dmitry)

More Online Helps

Win32 Programmer's Reference
Win32 Multimedia Programmer's Reference
OLE Programmer's Reference
Microsoft Windows Pen API Programmer's Reference
Microsoft Windows Sockets 2 Reference
Microsoft Windows Telephony API (TAPI) Programmer's Reference
Unix Manual Pages

greatis just4fun network