this post was submitted on 23 Aug 2023
86 points (96.7% liked)

Programming

17489 readers
205 users here now

Welcome to the main community in programming.dev! Feel free to post anything relating to programming here!

Cross posting is strongly encouraged in the instance. If you feel your post or another person's post makes sense in another community cross post into it.

Hope you enjoy the instance!

Rules

Rules

  • Follow the programming.dev instance rules
  • Keep content related to programming in some way
  • If you're posting long videos try to add in some form of tldr for those who don't want to watch videos

Wormhole

Follow the wormhole through a path of communities [email protected]

founded 1 year ago
MODERATORS
snowe
Ategon
[email protected]
86
A question about passwords | characters used in them (self.programming)
submitted 1 year ago* (last edited 1 year ago) by FinancesDrone98 to c/programming
63 comments fedilink hide all child comments
 

Why do so many companies and people say that your password has to be so long and complicated, just to have restrictions?

I am in the process of changing some passwords (I have peen pwnd and it’s the password I use for use-less-er sites) and suddenly they say “password may contain a maximum of 15 characters“… I mean, 15 is long but it’s nothing for a password manager.

And then there’s the problem with special characters like äàáâæãåā ñ ī o ė ß ÿ ç just to name a few, or some even won’t let you type a [space] in them. Why is that? Is it bad programming? Or just a symptom of copy-pasta?

you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 2 points 1 year ago (1 children)

Underappreciated fact: Bcrypt has a maximum of 72 bytes. It'll truncate passwords longer than that. Remember that UTF8 encoding of special characters can easily take more than one byte.

That said, this is rarely a problem in practice, except for some very long passphrases.

[–] [email protected] 1 points 1 year ago (1 children)

Bcrypt has a maximum of 72 bytes. It’ll truncate passwords longer than that. Remember that UTF8 encoding of special characters can easily take more than one byte.

Interesting: https://en.wikipedia.org/wiki/Bcrypt#Maximum_password_length

In the worst case a password is limited to 18 characters, when every character requires 4 bytes of UTF-8 encoding. For example:

𐑜𐑝𐑟𐑥𐑷𐑻𐑽𐑾𐑿𐑿𐑰𐑩𐑛𐑙𐑘𐑙𐑒𐑔 (18 characters, 72 bytes)

Makes me question if bcrypt deserves to be widely used. Is there really no superior alternative?

[–] [email protected] 2 points 1 year ago* (last edited 1 year ago)

Not only that, bcrypt could be run by GPUs and FPGA, that makes it more prone to bruteforcing attacks.

There are 2 modern alternatives: scrypt and argon2. They both require a substantial amount of memory, so gpu and hardware computation is no longer feasible.