where do i find crypt ?

["Chad A. Adlawan" <chadi@archangel.8eight8.net.ph>]

hello all,
  ive been trying to compile cops and crack but i keep on getting this error :

/tmp/ccc00945: In function `try':
/tmp/ccc00945(.text+0xb83): undefined reference to `crypt'

  can anyone tell me please where/what package do i get the crypt function from ?

TIA,
Chad