"I'm telling you this to protect you.  If you keep cracking, it's my
   job to make sure you can't continue."
    "I don't understand: isn't it obvious that nobody could crack pgp?
   Isn't it helpful if somebody were to do so publicly?  What is the
   reason for stopping me?"
   "How is it ever helpful to crack a cryptographic algorithm that is in
   use???"
   "It is how cryptographers improve them."