To add to J.R.’s last paragraph: in the past few decades,
***crack*** (as a verb) has acquired the meaning of “commit computer crime”. 
Most people consider *crack* to be synonymous with ***hack*** in this context;
some people in the computer security field prefer to use *hack* to refer to
solving difficult computer problems (such as penetrating security systems),
without the connotation of malice. 
See [Is the term “hack” more positive or more negative?]( on EL&U.