/>
Cracking involves the act of breaking into a computer system. The most common software crack is the modification of an application's binary to cause or prevent a specific key branch in the program's execution, it also involves copy prevention, trial/demo version, serial number, hardware key, CD check or software annoyances like nag screens and ad ware.

Phreaking:

Phreaking is another form of the art and science of cracking the phone network.

Hacking:

Hacking is usually referred to the act of attempting to circumvent or bypass the security mechanisms of an information system or network in an unauthorized manner.