Saturday, March 03, 2018

[tvuxbiuq] Password generation with a deck of cards

Easiest is to mark up the fronts of deck of 52 cards with lowercase a-z and uppercase A-Z.  (It's convenient how the numbers work out.)  Shuffle and get some random letters.  Drawing with replacement (shuffling after each draw) has slightly more entropy, but requires more effort.  Use the number cards (rejecting face cards) if you need to add some digits to satisfy password character class requirements.

We need a way of writing individual letters to distinguish uppercase from lowercase: c o p s u v w x z.  Maybe tilde or macron for lowercase, as these conveniently do not have ascenders.  Or cursive.

Slightly more sophisticated is to add 10 number cards from a separate deck, bringing the total up to 62: letters and digits. Add jokers or more face cards for punctuation.

Sites often disagree on what punctuation is permitted/required.  Is there a set of 2 (for jokers) or 3 (for face cards) which are usually permitted?

These would not be memorable passwords, so use a password manager.

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