Related Clues:

• It's broken after some thought
• Spy-school subject
• UPC part
• Cracker's target
• It may be cracked by a spy
• Programmer's concern
• It can't be understood until it's broken
• "The Da Vinci ___"
• Bed intruders?
• Do programming work
• Zip --
• Program listing?
• Write software
• Software basis
• Bar closing?