Cracking
NOPs are often involved when cracking software that checks for serial numbers, specific hardware or software requirements, presence or absence of hardware dongles, etc. This is accomplished by altering functions and subroutines to bypass security checks and instead simply return the expected value being checked for. Because most of the instructions in the security check routine will be unused, these would be replaced with NOPs, thus removing the program's functionality without attracting any attention.
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Famous quotes containing the word cracking:
“All round and round does the world lie as in a sharp-shooter’s ambush, to pick off the beautiful illusions of youth, by the pitiless cracking rifles of the realities of age.”
—Herman Melville (1819–1891)
“I also heard the whooping of the ice in the pond, my great bed-fellow in that part of Concord, as if it were restless in its bed and would fain turn over, were troubled with flatulency and bad dreams; or I was waked by the cracking of the ground by the frost, as if some one had driven a team against my door, and in the morning would find a crack in the earth a quarter of a mile long and a third of an inch wide.”
—Henry David Thoreau (1817–1862)
“Thou wilt quarrel with a man for cracking nuts, having no other reason but because thou hast hazel eyes.”
—William Shakespeare (1564–1616)