Why do password length limits exist?

Maximum lengths for passwords are a good thing to have. Long password denial of service is a thing that exists. Hashing algorithms that you use on the server side may have limits. More importantly, a known maximum password length allows you to test all of your password fields.

How will the length of a hashed password be affected by the length of the password as entered by the user?

With any serious hash scheme, the size of the hash will be constant, and more generally the value of the hash does not depend on the password in any detectable way.

What does it mean when passwords are hashed?

Hashing
Hashing performs a one-way transformation on a password, turning the password into another String, called the hashed password. “One-way” means that it is practically impossible to go the other way – to turn the hashed password back into the original password. If the passwords match, then login is successful.

How long should hashed password be?

If you are worried about DoS attacks using the password hash, 1000 or 1024 is a reasonable upper limit. why limit password length? At least let a user create a 100 character password 🙂 4 characters is a pretty dangerous lower bound for passwords as those are trivial to crack.

Why are some symbols not allowed in passwords?

Why do some password policies disallow certain special characters? The most common reason is that the software was not written by security-competent programmers. A “golden rule” of programming—in fact, the one that’s at the heart of nearly all vulnerabilities—is that you should never let bad data destroy your system.

Can hashed passwords be hacked?

Hashing is a one way encryption. Meaning, you cannot get the original text back from the hash. Now in information security, passwords are recommended to be stored in a hashed format so applications/systems can verify if the correct password is entered without them storing your password. This makes it harder to steal.

Can a hashed password be cracked?

Not all hashing is created equal. Some hashing schemes are more easily cracked than others. When hackers compromise a company to access its collection of users’ passwords, what they find and steal isn’t stored in a form that’s readable by humans—at least if the company has even a pretense of security.

Is there a reason to limit password length?

On Stack Overflow people even talk about there being no reason to limit password length and that max password lengths are a security warning.

Do passwords need to be hashed?

They should be hashed anyway, using a key derivation function (KDF) such as bcrypt. To help with performance, it might be worth placing a very large limit (e.g. 512 characters) on the password length, to prevent someone sending you a 1MB password and DoS’ing your server for 10 seconds whilst it computes the hash.

How can we speed up the way passwords are stored?

To speed up things we could limit passwords to a certain length, then just pad all passwords less than that length with a predefined byte. As a result we only have to handle a buffer of fixed length and not have to worry about working out the length of someones novel of a password.

What is the maximum character limit for a password?

If you set your password max length to 100 characters, every password field should allow you to type in at least 101 characters. This means that if a user uses a password manager to generate a 200 character password, your password set page has a chance to inform the user that they have entered too many characters and that they need to enter less.