Minimimum number of clues to solve password
March 31st, 2023 at 4:04:46 AM
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My memorable info is 12 characters long, and I do not use any character 4 or more times. Somehow John knows this.
My bank always asks for 3 characters from my mem info, presumably at random, but always in order (they'll ask for 3, 8, 11, never 8, 3, 11)
If John is eavesdropping on me when I give the characters out, but he doesn't know which numbers they are, just that they are in order, what's the minimum and maximum number of unique sets that would John have to hear in order to fully know my meminfo?
My bank always asks for 3 characters from my mem info, presumably at random, but always in order (they'll ask for 3, 8, 11, never 8, 3, 11)
If John is eavesdropping on me when I give the characters out, but he doesn't know which numbers they are, just that they are in order, what's the minimum and maximum number of unique sets that would John have to hear in order to fully know my meminfo?
March 31st, 2023 at 4:31:55 PM
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It depends on the code, but in some cases, I don't think it's possible.
Take the following 4 codes:
123412341234
234123412341
341234123412
412341234123
Each of the 64 possible sets of 3 characters (111, 112, ..., 443, 444) is in each code.
Even if all 64 codes are mentioned, there is no way of knowing for certain which one it is.
