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Entering a particular password will let one "sign" one's posts with the tripcode generated from that password, while trying to take another user's tripcode and compute their password from it (for instance, to make posts that appear to come from a particular person) is computationally difficult. For those who want a custom tripcode, however, there are custom tripcode generators available, such as Meriken's Tripcode Engine<ref> Meriken's Tripcode Engine </ref> and MTY_CL.