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Crackmes, reversemes and keygenmes generally have similar protection schemes and algorithms to those found in proprietary software. However, due to the wide use of packers/protectors in commercial software,[further explanation needed] many crackmes are actually more difficult as the algorithm is harder to find and track than in commercial software.[further explanation needed]
A keygenme is specifically designed for the reverser to not only find the protection algorithm used in the application, but also write a small keygen for it in the programming language of their choice.
Most keygenmes, when properly manipulated, can be self-keygenning. For example, when checking, they might generate the corresponding key and simply compare the expected and entered keys. This makes it easy to copy the key generation algorithm.