Trap Doors

When developing large programs, programmers insert instructions for additional code and intermediate output capabilities. The design of computer operating systems attempts to prevent this from happening. Therefore, programmers insert instructions that allow them to circumvent these controls. Hackers take advantage of these trap doors.

There are often 'harmless' Trojans in software called 'Easter Eggs'. These are programs within the real program - usually that have nothing to do with the real host software. They can be games, lists of developers, pictures or any other sort of file. A list of these is maintained at www.eeggs.com.