Specific to the security of passwords: hashing, entropy, cracking, resets, lockouts, etc.

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One liner to create passwords in linux?

How do you create a readable password using bash with one line? What if i'm looking for 128 bits of entropy? EDIT By readable I mean the 94 printable ascii characters (without space). It can use ...
23
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3answers
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For an HTTPS web application, is it worthwhile to encrypt the password before POSTing it, to keep a MITM attacker from harversting it?

Our application has recently gone through penetration testing. The test found one critical security breach, which is essentially: The problem: Attacker sets up a WiFi spot. User enters our site ...
23
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10answers
6k views

Intel How Strong is Your Password page, good advice?

I came across this Intel How Strong is Your Password? page which estimates how strong your password is. It has some advice on choosing better passwords including that you should use multiple ...
23
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5answers
2k views

Should passwords be revealed in error message?

I am having pet-peeve with PHP's PDO class. As you can see on the Warning note: it reveals database password by default if an exception was not caught (when display errors is on which is a probable ...
23
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2answers
3k views

Passwords in plaintext?

I'm doing some research on the App of my telephone operator. I started Burp Suite on my Mac in proxy mode, I opened up the App on my iPhone and started to sniff some traffic. I pressed the "login" ...
23
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1answer
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Facebook password lowercase and uppercase

Recently I logged into my Facebook account and then noticed that my caps lock was on. So I tried to log in again with and without capslock on. I got in both times. Then I tried to log in with the ...
22
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7answers
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Why don't people hash and salt usernames before storing them

Everyone knows that if they have a system that requires a password to log in, they should be storing a hashed & salted copy of the required password, rather than the password in plaintext. What I ...
22
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3answers
2k views

Does overlaying the mouse on a virtual numeric keyboard really protect against keyloggers?

I just saw for the first time a new way to enter a password, at the Banque Postale (French Bank). You are given a virtual numeric keyboard and to type you can just leave the mouse cursor over a number ...
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6answers
1k views

Online password managers

Can online password managers be used for storing and managing passwords? I mean from the security point of view. I understand that those systems can be different and some deserves more trust than the ...
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5answers
2k views

Do spaces in a passphrase really add any more security/entropy?

I often see passphrase suggestions written as a sentence, with spaces. In that format are they more susceptible to a dictionary attack because each word is on it's own as opposed to a large unbroken ...
22
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4answers
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What should be used as a salt?

I always hear that it is best to use salts on top of stored passwords, which then somehow gets concatenated and hashed afterwards. But I don't know what to use as a the salt. What would be a good ...
22
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5answers
3k views

Security impact of using a public password for free WiFi

We have a WiFi network that we want to be public and free. Does having a password that is known to everyone provide any additional security advantage to the people using this network as opposed to ...
22
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4answers
11k views

Demystifying Web Authentication (Stateless Session Cookies)

I'm currently researching user authentication protocols for a website I'm developing. I would like to create an authentication cookie so users can stay logged in between pages. Here is my first ...
22
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4answers
6k views

How secure is Windows 8's Picture Password login?

The final Windows 8 build has been released to manufacturing. One of the new features of Windows 8 is "Picture Password", where the end user logs on to Windows by clicking a specific pattern on the ...
21
votes
4answers
5k views

Is using SHA-512 for storing passwords tolerable?

I know that the best options to use for storing passwords are bcrypt/PBKDF2/scrypt. However, suppose you have to audit a system and it uses SHA-512 with salt. Is that "fine"? Or it is a vulnerability ...
21
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4answers
9k views

Should I change all my passwords due to heartbleed [duplicate]

Should I change all of my online passwords due to the heartbleed bug? Edit: I found a list of vulnerable sites on GitHub and checked all my critical sites. Everything I was really concerned with ...
21
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3answers
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Doesn't plaintextoffenders.com just provide attackers with a good list of sites to attack for passwords?

On the face of it, PTO seems like a good idea in educating people about password security. On the other hand, if I were an attacker, PTO would be the first place I would start if I wanted to start ...
21
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4answers
2k views

What are spambots doing with unintelligible login attempts?

After constantly being under attack in phpBB, I created a new forum by hand, which successfully prevents spam bots from registering, and I get a report for every failed login attempt, telling me the ...
21
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6answers
7k views

Is AES encrypting a password with itself more secure than SHA1?

This isn't really a practical question, but more a question of curiosity. I heard a CS professor recommend stepping up from md5ing passwords not to SHA1, but to AES encrypting the password using ...
21
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5answers
3k views

Do non-keyboard characters make my password less susceptible to brute forcing?

I can put characters in my password for which there are no keys on a keyboard. On Windows, Alt+#### (with the numpad) inserts the character for whatever code you type in. When I put this in a ...
21
votes
5answers
4k views

Password strength and banks 4 pin code?

Why is it that some security advisers recommend using an 8 character password with upper, lower, digits, and symbols while banks only use a 4 digit number pin for debit and 3 digit pin for credit ...
21
votes
6answers
2k views

Why do some sites prevent users from reusing their old passwords?

I have always wondered why it is that bad to reuse old passwords; it should not be the end of the world if we happen to use an old password that we previously used. After all, I believe most of the ...
21
votes
4answers
3k views

How would you store a 4 digit pin code securely in the database?

I'm familiar with password hashing, using salts, bcrypt etc. But it doesn't seem like this would work to store a 4 digit pin code since the attacker could try all 10,000 combinations quite quickly. ...
21
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5answers
940 views

Hashed password storage with random salt

Ever since I've been making sites that require a user to log in with a username and password I've always kept the passwords somewhat secure by storing them in my database hashed with a salt phrase. ...
21
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5answers
2k views

Is my bank storing my password in plain text? [duplicate]

My bank (and every bank I've come across) only ever asks for individual characters from my password when logging in. Is my bank storing my password in plain text?
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5answers
2k views

How can I choose a strong password that is easy use on a smartphone?

Typing on a smartphone is tedious. Special characters are the hardest; lowercase letters are generally the easiest. But even a long all-letter passphrase like "correct horse battery staple" is ...
21
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5answers
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Is it possible to increase the cost of BCrypt or PBKDF2 when its already calculated and without the original password?

I just wanted to know if you can increase the cost (iterations) of those two algorithms off-line. I want to increase the cost every year of my users passwords. One solution is to recalculate them ...
21
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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 ...
21
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2answers
1k views

How can we accurately measure a password entropy range?

I've given myself the task of writing code that determines the strength of a password, and really want to break out of a lot of already established ways we do that, as they're often lacking, not ...
20
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5answers
2k views

When hashing passwords, is it ok to use the hashed password as the salt?

I don't like this idea. But I can not come up with a technical argument against it. Can somebody explain it to me? The basic idea is: $passwd = 'foo'; $salt = hash($passwd); $finalHash = hash($passwd ...
20
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9answers
1k views

Is a simple, but very long password a good password?

Is a password like wwwwwwwwwwwwwwwwwwwwwwwww9 (25x 'w' and a number) secure? It would be easy to remember.
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5answers
1k views

Why do some websites and programs restrict password characteristics?

There are some websites and even programs that I use that have rediculous password restrictions. Lots of forums for instance restrict passwords to ~32 characters. Others enforce a restricted charset. ...
20
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5answers
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What's the practical limit for rainbow-table based bruteforce?

Say we have a hash of a password. The password can be considered to be made of of totally random characters and has a fixed length of N. The hash is SHA1(password+salt), where the salt is of length M. ...
20
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10answers
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Password Management within an Organisation

Within an organisation there are many passwords such as those for root accounts on servers, hosting accounts, router logins and other such things, that need to be kept track of. I know in some ...
20
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3answers
4k views

Password manager vs remembering passwords

I have always thought that you are not supposed to use a password manager but to keep your passwords in your head, but lately I have thought about the pros and cons of having a password manager. Some ...
20
votes
4answers
5k views

Security of passphrase-protected private key

If an attacker obtains a private key that was created with no passphrase, he obviously gains access to everything protected with that key. How secure are private keys set up with a passphrase? If an ...
19
votes
12answers
3k views

Why do we even use passwords / passphrases next to biometrics?

In the last couple of days there were a lot of talking about passwords and passphrases, not only here, but on several blogs and forums I follow (especially after XKCD #936 saw the light of this ...
19
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4answers
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The registration confirmation email contains my password: do they keep it in plaintext?

I was kind of shocked when I just received my confirmation mail from the shop where I just registered myself: they sent my username (which is my email address) and the password I typed in. The ...
19
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5answers
1k views

Is it alright to tell everyone your encryption information?

I have an account in an online banking system and they have the FAQ with something like this: How secure is the <Online Banking System Name>? Each page you view and any information ...
19
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2answers
12k views

Why are GPUs so good at cracking passwords?

What is it about GPUs that lets them crack passwords so quickly? It seems like the driving force behind adopting good key-derivation functions for passwords (bcrpyt, PBKDF2, scrypt) instead of ...
19
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4answers
3k views

Why is using salt more secure?

Storing the hash of users' passwords, e.g. in a database, is insecure since human passwords are vulnerable to dictionary attacks. Everyone suggests that this is mitigated via the use of salts, but the ...
19
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4answers
7k views

Google Account: implications of using application-specific passwords

In the wake of the recent Mat Honan story I decided to try out two-factor authentication on my Google account. But in order to keep using it with Exchange, the Android OS, Google Talk and Google ...
19
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2answers
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Does bcrypt have a maximum password length?

I was messing around with bcrypt today and noticed something: hashpw('testtdsdddddddddddddddddddddddddddddddddddddddddddddddsddddddddddddddddd', salt) Output: ...
19
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3answers
1k views

Why do some sites block pasting into username or password input fields?

I use a few websites that prevent me from copying & pasting into the username or password fields. It's quite frustrating when using a password manager, and if anything I'd think it discourages ...
18
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6answers
2k views

Why do we ask for a user's existing password when changing their password?

In a web applications context, when a user wants to change their current password, generally they would have to enter their current password first. However at this point, the user has already been ...
18
votes
5answers
3k views

Does too long a salt reduce the security of a stored password hash?

Suppose we have passwords that are statistically 7-8 characters long. Is appending a 200 character long salt less secure than a 5 character salt, because of the similar hash function inputs? I was ...
18
votes
3answers
9k views

Router password vs MAC filtering?

I just bought a Galaxy S4, and it didn't connect to the WIFI in my house (I have a 14$ router). After a bit of testing, I've decided to leave my connection open without a password, but added the ...
18
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7answers
848 views

Are common passwords at particular risk?

The question Should we disallow common passwords like “password” and “12345”? on User Experience immediately made me think that these common passwords were extremely dangerous not because they are ...
18
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3answers
6k views

Deleting a Java Object securely

I know that in order to delete a Java object I should use character array instead of String, since I can safely erase (rewrite the character array with other data) its content. This seems not to be ...
18
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1answer
1k views

Why does Facebook bother comparing old and new passwords?

An answer to this question says Facebook generates a bunch of password guesses to see if they hash the same as a previous version of the password. Why bother? If a service forces every password to ...