Cd key

Most keys are not effective in stopping copyright infringement of software as these keys can be easily distributed. In addition with improved communication from the rise of the Internet more sophisticated attacks on Keys such as cracks (removing the need for a key) and CD key generators have become common.

Because of this, software publishers are increasingly turning to active methods of verifying that keys are both valid and uncompromised.

These "active methods" usually involve requiring periodical validation of the CD key with an internet server (for games with an online component, such as Battle.net, this is easily done whenever the user signs in). The validation can then be performed on the server side, preventing cracks tampering with it (as they do on the client side). The server can also keep a blacklist of all CD keys known to be invalid or which have explicitly been banned, and deny them access.