Hacking can mean several things: it can refer to finding weaknesses in a computer or computer network, the act of modifying the software or hardware of a computer, or to a programming subculture. In all of these cases, one who uses hacking for any means is known as a hacker. It should be noted that what is usually called hacking is actually cracking, and refers specifically to the circumvention of computer security. There is also a difference between those who use hacking to engage in crime–called “black hats”–and those who use hacking for more ethical reasons, such as to test the security of a computer system with the consent of the system’s operator–known as “white hats.”
Both Dennis Nedry and Lex Murphy are hackers. Nedry was hired by InGen as a programmer to manage Jurassic Park’s automated systems, but was also a hacker, perhaps used as a “white hat” hacker to test the security of the park’s computers; however, this allowed Nedry to place his own commands and lines of code in the system so that he could disable Jurassic Park’s automated security systems and steal dinosaur embryos, making him a “black hat” hacker. Lex, in contrast, is presumably a much more casual hacker, who hacks systems for entertainment rather than monetary gain. Nedry originally planned to disable the park’s security and restore it after delivering the embryos to his contact at the East Dock, but his death prevented this from coming to pass. Lex later restored the park’s systems herself.