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?
Yes its bad programing. These restrictions suggest that the company is either doing improper storage and processing, or does not understand how to deal with passwords.
The proper password storage is a hash. This is a cryptographic function that is easy to do and imbossible to undo. The hash function operates on the underlying binary representation of your password, and doesn't card what letters or symbols are in it. A program should take your password, hash it, and compare the result to the hash they have in their detebase.
The current recomended hash algorythm is called 'bcrypt'. Depending on the implementation, the input is between 50 and 70 bytes (the spec was a little unclear so people defined the inputs diferently, but the algorithe is the same). This means a password should be able to take at least 50 normal keyboard characters, including letters, symbols, and spaces. Anything less than that indicates a poor practice on behalf of the website.
(a lot of this is simplified. There is some variation and nuance that I don't think affects the main idea)