Password length requirement
Password length requirement
Last week, I tried to register for a service and was really surprised by a password limit of 16 characters. Why on earth yould you impose such strict limits? Never heard of correct horse battery staple?
This is my biggest pet peeve. Password policies are largely mired in inaccurate conventional wisdom, even though we have good guidance docs from NIST on this.
Frustrating poor policy configs aside, this max length is a huge red flag, basically they are admitting that they store your password in plan text and aren’t hashing like they should be.
If a company tells you your password has a maximum length, they are untrustable with anything important.
Lemmy-UI has a password limit of 60 characters. Does that make it untrustworthy?
OWASP recommendation is to allow 64 chars at least:
The lemmy-UI limit is reasonably close and as everything is open source, we can verifiy that it does hash the password before storing it in the database.
There is a github issue, too.
It being open source helps because we can confirm it’s not being mishandled, but it’s generally arbitrary to enforce password max lengths beyond avoiding malicious bandwidth or compute usage in extreme cases.
I would add if they require a short "maximum length." There's no reason to allow someone to use the entirety of Moby Dick as their password, so a reasonable limit can be set. That's not 16 characters, but you probably don't need to accept more than 1024 anyway.
Why not? You're hashing it anyways, right?
Right?!
"If a company tells you your password has a maximum length..."
Uhhh no. Not at all. What so ever. Period. Many have a limit for technical reasons because hashing passwords expands their character count greatly. Many websites store their passwords in specific database columns that themselves have a limit that the hashing algorithm quickly expands passwords out to.
If you plan your DB schema with a column limit in mind for fast processing, some limits produce effectively shorter password limits than you might expect. EVERYONE has column limits at least to prevent attacks via huge passwords, so a limit on a password can be a good sign they're doing things correctly and aren't going to be DDOS'd via login calls that can easily crush CPUs of nonspecialized servers.
Can you not simply have a hashing algorithm that results in a fixed length hash?
Just in case someone runs across this and doesn't notice the downvotes, the parent post is full of inaccuracies and bad assumptions. Don't base anything on it.
It doesn't matter the input size, it hashes down to the same length. It does increase the CPU time, but not the storage space. If the hashing is done on the client side (pre-transmission), then the server has no extra cost.
For example, the hash of a Linux ISO isn't 10 pages long. If you SHA-256 something, it always results in 256 bits of output.
On the other hand, base 64-ing something does get longer as the input grows.
Why not just store the first X characters of the hashed password?