In password security, the longer the better. With a password manager, using more than 24 characters is simple. Unless, of course, the secure password is not accepted due to its length. (In this case, through STOVE.)
Possibly indicating cleartext storage of a limited field (which is an absolute no-go), or suboptimal or lacking security practices.
The backend should care though. Even if strings can have an unlimited amount of characters, you don’t want to go and hash a gigabyte of data. In lower level languages you don’t have magic strings either so you might do something like
char password[64].There’s many reasons to limit raw password length. Not many good ones to have it as small as 24 (or even 64) though.
There should be a limit. It should be so high that we never hear about it. 1MB for example.
Exactly. The tax on hashing the password can’t be ignored and if you’re doing this enough times it can kill a system. 24 characters is too low. I’d say 100 characters is enough for most use cases. 1024 if you’re feeling 1337.
Sure, but when we talk about the computation then the number of rounds is by far the more important factor compared to password length.
The discussion is about whether 24 characters indicate cleartext though - not whether password lengths should be in the gigabytes.
Seems reasonable.
I agree you might have threat actors looking to DoS your system if there’s a publicly exposed REST endpoint accepting gigabytes of data. That has nothing to do with the discussion on password hashing though.
The claim was that a limit on passwords implies plaintext storage. It doesn’t. There is no such thing as unlimited on computers.
quoting the post:
It was not a claim that it certainly is plaintext storage. It was claimed to be a possibility. AND provided an alternative explanation.
Maybe you’re more confident than me in good practices and implementations across all services. But I’ve seen enough to know that’s not always the case. It’s good to be skeptical on anything related to security.
No it doesn’t.
It does.
/80’s hacker turned Software Engineer turned Cybersecurity professional
Lmao.
As if my title isn’t almost exactly the same.
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Don’t worry, I’m autistic myself and understand how difficult it can be to parse “it’s thus irrelevant how many characters the user’s password consists of” to mean something besides “all implementations must accept an unlimited amount of characters”.
I do believe the point was understood by the general reader however.
What an awful thing to say. Go question your motives.
Curiousity: Could you please explain what was awful about the comment you responded to?
For context, I’m also autistic.
I don’t think I’m autistic but I am confused too :/
There is no good reason so send the passwors itself to the server. Send the hash and you will have a fixes length of data to send anyway.
And even if insist in sending the password over the wire, there is no problem on the backend to handle longer passwords than that, so that no one will run into a limit in practice. We’re talking about bytes here, not even a kb.
Proper hashing of a password includes a salt that should be kept private. This means the password should definitely be passed to the server in plaintext. The server adds the salt to the password, then hashes it.
This adds more protection should an attacker somehow manage to get access to your hashed passwords. Even if they identify the type of hashing mechanism used it will prevent the use of rainbow tables, dictionary attacks, etc. against the hashes.
If that were the case you could still hash it on the client side, forcing it to be a certain size and then hash it again on the server with the right salt. I don’t think there’s a real disadvantage to hashing a hash.
While I’m not arguing for doing the crypto client side, the salt isn’t needed to be private - only unique.
It definitely needs to be private. If an attacker can obtain both the password hashes and the salt(s) (via the same database vulnerability for example) then they have everything they need to run offline attacks against the passwords.
No, it most definitely does not need to be private. The idea with salt is to invalidate rainbow tables. If you’re “keeping it private” it’s just another password.
https://en.wikipedia.org/wiki/Salt_(cryptography)
The salt is specifically to invalidate pre-generated rainbow tables, and doesn’t need to be kept private. It only needs to be unique.
The attacker generates rainbow tables by running common passwords through known hashing algorithms. So I run “password1” through a bunch of different algorithms, and save the results of each. Notably, generating decently large rainbow tables takes a lot of time, processing power, and storage space. Because you don’t just use common passwords; You’re basically running a brute force/dictionary attack on your own computer’s hashing algorithm.
Now if a database is unsalted, I can search for matching results against my rainbow table. When I see a match, it tells me both which users had that password and which hashing algorithm they were using. So now I can narrow down my focus to only using that algorithm.
But if a database is salted, all of my pre-generated tables are useless. Even if someone used “password”, it won’t match my rainbow tables because the hash was actually fed “password{hash}” instead. And even if multiple users used “password”, each salt is unique, so I don’t see a bunch of repeated hashes (which would point to those accounts using the same password). I would now need to generate all new tables with the salts I stole in order for my rainbow tables to be usable again. And even then, I’d need to repeat that table generation for every user.
you absolutely should not be hashing client side. You need to securely transmit the password to the server where it is hashed. You do not want clients knowing /how/ the password is salted/hashed. this lowers your security overall.
If you’re doing hashing and salting on the client then yep it’s useless, no difference to just using a hash output as a password.
If on the other hand you’re doing a zero-knowledge password proof method then it’s quite secure. As the password is never transmitted over the network, not even the server knows what it is, but can still verify the user has the correct one.
There’s some software that hashes the password clientside before sending it, sure. But it still should be hashed serverside too.
If the server hashes a hash, the plaintext password’s length is still irrelevant
That’s not true. There’s limits everywhere.
At no point the server has to deal with the length of the plaintext