5 ms·
Individual passwords don’t have entropy.
by spacehome 5y ago
Individual passwords don’t have entropy.
- MattPalmer1086 5y agoYou can calculate Shannon entropy of an individual password, as the number of bits per char. A password of "aaaaaaa" will have a much lower entropy than "axipeY7". What am I missing?
- MattPalmer1086 5y agoReplying to self... I guess it's not a useful measure of password strength, even if possible. Any password that doesn't repeat any letters will have identical entropy by this measure. So 123456789 will be the same Shannon entropy as Ar4e$hUa^
- throwawayffffas 5y agoEntropy is really a measure of password length.
- MattPalmer1086 5y agoThat's basically right for passwords. Of course, if we impose password complexity requirements (e.g. must have a digit or an uppercase letter), it actually reduces the entropy in the password!
- aeternum 5y agoEntropy is a measure of the potential state space. So password length matters a lot but so does the size of the character set.