Timeline for Is Entropy all that matters in a Password? [duplicate]
Current License: CC BY-SA 3.0
12 events
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| Jun 2, 2017 at 2:44 | comment | added | SDsolar | CrDj”(;Va.*NdlnzB9M?@K2)#>deB7mN | |
| Feb 22, 2016 at 16:35 | comment | added | dr jimbob |
However a password like FootballPractice or FootbalPractic is still incredibly weak (two random words chosen from a reasonable sized dictionary generally have ~13 bits of entropy), so at best FootballPractice would be originally be say 26 bit words, except the phrase is meaningful and likely not random, so its much lower entropy less than this. Even if you added say ~6 bits of entropy by truncating letters, it's still within the regime of online brute-force attacks. A password's entropy is the base-2 logarithm of the number of possible passwords it was chosen from.
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| Feb 22, 2016 at 16:29 | vote | accept | Magmagod | ||
| Feb 22, 2016 at 16:26 | comment | added | dr jimbob |
While longer passwords tend to have higher entropy its not always true -- it depends on the mechanism used to generate the password. E.g., choosing a common 8-character password like password (takes up 8 bytes in ASCII) has a very low entropy you could find this on a list of the top 16 passwords so about 4 bits of entropy (2^4 = 16). Meanwhile Bx.hC&V a 7-char password generated by randomly selecting one of 94 printable characters (97^7 = 64847759419264 ≈ 2^45.9 ) has about 45.9 bits of entropy. Modifying words in your passphrase by truncating a letter adds a couple bits of entropy.
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| Feb 22, 2016 at 16:08 | comment | added | S.L. Barth is on codidact.com | @Magmagod Ah, now I understand the problem. There is the famous XKCD scheme. We have a page about it here; you may find that page useful. | |
| Feb 22, 2016 at 16:06 | history | closed | AviD♦ | Duplicate of XKCD #936: Short complex password, or long dictionary passphrase? | |
| Feb 22, 2016 at 16:06 | comment | added | SilverlightFox | Check out diceware. Each word gives you an additional 13 bits of entropy. | |
| Feb 22, 2016 at 16:01 | comment | added | Magmagod | Well i thought this up just because i have a real hard time remembering random passwords and i'm not exactly creative when creating passwords, normally i use a password manager, but i still need a reasonable master password to protect the others, i thought about doing something similar to this so i decided to come ask | |
| Feb 22, 2016 at 15:58 | comment | added | S.L. Barth is on codidact.com | Don't assume that a few typos protect you from a dictionary attack. Any decent dictionary attack will include typos and common substitutions. | |
| Feb 22, 2016 at 15:56 | answer | added | SilverlightFox | timeline score: 2 | |
| Feb 22, 2016 at 15:45 | review | First posts | |||
| Feb 22, 2016 at 15:59 | |||||
| Feb 22, 2016 at 15:42 | history | asked | Magmagod | CC BY-SA 3.0 |