21-07-2020, 10:33 AM
Many amateur codebreakers produce solutions that are indeed reproducible (when the method is comprehensible), but suffer from being non-unique. That is, their solution is only one of multitudes of plausible solutions that can be generated using the same method that produced their proposed solution. That, to me, is a good filter for distinguishing real and false solutions. (Related topics: multiplicity, and unicity distance)