A set of requirements regarding password creation, storage, and usage. These requirements often constrain several characteristics of passwords. So, a password policy is a set of rules designed to enhance computer security by encouraging users to employ strong passwords and use them properly.

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303
votes
12answers
48k views

What technical reasons are there to have low maximum password lengths?

I have always wondered why so many websites have very firm restrictions on password length (exactly 8 characters, up to 8 characters, etc). These tend to be banks or other sites I actually care about ...
32
votes
9answers
8k views

How long should the password be?

The minimum password length recommended is about 8 characters, so is there any standard/recommended maximum length of the password?
18
votes
3answers
2k views

Should I have a maximum password length?

I'm creating a webapp, and part of my authentication method is password length. Should I put one in place? (say, 50 characters?) Or should I just put a minimum length (Currently at 6). Are there ...
22
votes
5answers
2k views

Is it common practice to log rejected passwords?

While selecting unique passwords for each purpose is a great idea, in practice this rarely happens. Therefore many select passwords from a personal pool of passwords that are easily remembered. When ...
7
votes
4answers
550 views

Doesn't imposing a minimum password length make the password weaker by reducing the number of possible combinations?

I thought the strength of a password depended on the total number of possible combinations. Therefore, allowing longer passwords should be safer because you then have more possibilities. But why do ...
4
votes
1answer
312 views

How does the mobile security technology APNS and 3LM work?

APNS is an iPhone technology that assists with mobile push. 3LM is a BIOS-level security technology embedded in certain Android phones. I recently got off the phone with Boxtone and they said they ...
25
votes
8answers
8k views

Why Disallow Special Characters In a Password?

The culprit in this case is a particular (and particularly large) bank that does not allow special characters (of any sort) in their passwords: Just [a-Z 1-9]. Is their any valid reason for doing ...
8
votes
4answers
2k views

Passwords - any statistics on user behavior?

I'm looking for analyses of how users choose and use passwords. I'm sure there are many resources out there that analyze user passwords. For instance, I've seen many people analyze dumps of password ...
8
votes
2answers
438 views

Banning specific passwords?

There have been a couple of questions about enforcing good passwords, so I thought I'd add my own: In addition to enforcing a minimum Shannon entropy, would it generally be a good practice to ...
6
votes
3answers
443 views

An alternative to traditional passwords: is there some merit to this idea?

If you've got a website aimed at people that are not neccessarily technically proficient, letting new users choose their own password isn't very secure because of the simple fact that a lot of people ...
3
votes
5answers
2k views

Password reset links: random value or authenticated message?

Which is better? Create tamper-proof encrypted password reset token which contains the user id and the expiration time within the encrypted token. Generate a random token and store it in the ...
3
votes
7answers
1k views

Is it possible to detect password length from hash? Does doubling your password add more security?

Assuming a service doesn't store a plain text password, am I right in saying that the answer to this question depends on the service? On a bad service, the hash length is related to the password ...
1
vote
3answers
223 views

Should I trust my bank after this [closed]

I have just discovered that I can login to my bank with passwords that is not mine. Example: My password is "1234" but I am authorized with all possible post characters. For example "12345" or ...
168
votes
7answers
36k views

Why would you not permit Q or Z in passwords?

Jetblue's password requirements specify that, among other stringent requirements: Cannot contain a Q or Z I can't fathom a logical reason for this, unless it were say, extremely common for the ...
19
votes
10answers
4k views

Best password strength checker

In XKCD #936: Short complex password, or long dictionary passphrase? Jeff claimed that password cracking with "dictionary words separated by spaces", or "a complete sentence with punctuation", or ...
13
votes
5answers
7k views

Is saving passwords in Chrome as safe as using LastPass if you leave it signed in?

Justin Schuh defended Google's reasoning in the wake of this post detailing the "discovery" (sic) that passwords saved in the Chrome password manager can be viewed in plaintext. Let me just directly ...
12
votes
3answers
383 views

Is it inconsistent to tell users to “not click on password links in email”, and requiring clicks on “forgot password” links?

On one hand, IT Security shops have been telling users to not click on links in email because they can do damage to your computer, or phish your personal information. Many of those issues are ...
35
votes
10answers
3k views

Why do password strength requirements exist?

Password strength is now everything, and they force you to come up with passwords with digits, special characters, upper-case letters and whatnot. Apart from being a usability nightmare (even I as a ...
32
votes
8answers
2k views

Who is responsible for the strength of user's passwords?

Who is responsible for a user's password's strength? Is it us (developers, architects, etc.) or the user? As a web developer, I've frequently wondered whether I should enforce the minimal password ...
25
votes
12answers
3k views

How secure are passwords made of whole english sentences

I often read as an advice to build strong passwords, just to think about a sentence and then take the initial letters. For example take a nonsense sentence like "I watch Grey's Anatomy at 9.40" gives ...
23
votes
6answers
9k views

Sharing wifi at a business - Bad Policy?

Is it safe for a small business to let customers use their wifi while waiting? My friend is starting up a small dentistry practice (1 dentist), and I'm setting up his computers/wifi as a favor. ...
1
vote
3answers
2k views

What do I need to do to secure log-in and registration for my website?

What security features do I need to have in-place to ensure that my website log-in and registration forms are secure?
11
votes
3answers
2k views

Why are passwords limited to 16 characters?

What is the reason that most websites limit to 16 characters? I would have thought the longer the password the more difficult it makes it for someone to crack it? Is it something to do with hash ...
4
votes
2answers
570 views

How often should passwords change?

I'm asking two very related questions As an admin what policies should be enforced regarding the frequency of password changing? I have an idea that users should be forced to change their ...
4
votes
3answers
624 views

password complexity policy for non “English” passwords

In an internationalized application, what is the best practice for a policy on complexity of passwords? I am not having luck searching for the answer. Wikipedia lists these items for password ...
3
votes
8answers
416 views

Generate user a password instead of asking for one?

I'm trying to weigh the benefits of not allowing users to create their own passwords, but must pick out of a generated selection. Are there any examples of sites that use this approach? Workflow ...
9
votes
3answers
243 views

Is there any conceivable reason to prevent a password change in an authentication system?

I connect to the VPN of another company with a company-specific username and password (they aren't giving everyone the same password to every company to access it or anything ridiculous like that.) ...
8
votes
4answers
2k views

Is forcing users to change passwords useful?

In many places, there's a policy that force the user changing it's password once a few months. The logic here is, that even if the password have leaked somehow, it'll be abused only for a relatively ...
5
votes
2answers
490 views

Requiring regular password change but storing previous paswords?

My bank requires me to change my password regularly but then they can detect if my password was used before. They probably store the old password (possibly hashed) in order to detect it. I think this ...
5
votes
6answers
2k views

Does having a minimum number of digits improve password security?

Some password systems will enforce at least X of a type of character - a common one I see is 'minimum 3 numeric characters'. As far as I understand, simply allowing certain character classes, like ...
4
votes
2answers
121 views

Guidance for “image based” password reset challenge

Thycotic has a Password Reset Server that allows the user to select from several images. What general guidance is there for an image-based password reset challenge question? Examples may include ...
4
votes
2answers
544 views

Would a massive blacklist of guessable passwords be useful? [duplicate]

Suggestions to make a good password all focus on creating a string that a computer (or more likely, a network of computers with multiple GPUs) can not guess. Putting a password meter for when users ...
3
votes
2answers
224 views

Is there a site like plaintextoffenders.com that shames companies that force insecure passwords?

I recently came across http://plaintextoffenders.com/ and I liked the idea. I wondered if there was a similar site that shames websites that force insecure passwords? I personally have a list of a ...
3
votes
3answers
229 views

When changing a password, does it have to be completely different?

When changing a password how important is it to have a significantly different one? For example is it bad to reverse the sequencing of the old password to make a new one or change a few numbers?
2
votes
0answers
75 views

How can a service shorten a password if it is not stored in plaintext? [duplicate]

Possible Duplicate: How can Microsoft validate a shorter password on Microsoft accounts (MSDN)? My Microsoft password was 18 characters long and when I updated to Outlook.com it started to ...
0
votes
2answers
503 views

What are RealVNC 5.0 Authentication Protocol Security Limitations?

In the old version of RealVNC, the password length was limited to 8 characters which was easier to be cracked. They have now increased the password length by 255 characters, will this make Realvnc ...