Is there a legitimate reason to use 20 characters over 16? Genuinely asking. Bitwarden considers them both “strong”, taking centuries to crack.
Well the more characters you have the higher the entropy of the password and the harder it would be to crack. So when you don’t have to remember the password yourself there’s no reason not to use a very long password if the service you’re using allows it.
Except no one cracks passwords. Vast majority of hacks is through social networking and trojans. The days of password cracking are long over especially considering most services lock you out after several failed attempts.
The main argument for using a password manager is so you can have a different password for every service. This way if they manage to obtain one password they can’t access everything.
It also makes rotating passwords a lot easier so that way you’re not using the same password forever. If your password gets out hopefully it’s changed before they use it.
Offline password cracking is still very much a thing. They steal the entire password database then crack it offline at their leisure, not live against the regular login.
Several measures are required to defend against this:
- Hash seeds defend against rainbow tables.
- Password length & complexity as well as using computationally-intensive hash algorithms defend against the brute-force cracking.
- Password managers help with length and complexity, sad well as promote not reusing passwords.
There’s realistically no reason not to generate the max password. The different in possibilities between a password with 16 characters and one with 20 (using a-zA-Z0-9!@#$%^&*()?-+." which isn’t even all the options) is 1.2E30 v s 4.13E37. That’s seven orders of magnitude from 4 characters. The difference between $1 and $10,000,000. But to be fair, 1.2E30 possible combinations is kind of a lot already, but why not add a few more characters just for the hell of it?
If you always use the maximum then the length of your password becomes predictable which reduces the number of permutations.
It’s probably better to use a password of around 60-100% of the maximum
