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

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27
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8answers
3k views

Why is password hashing considered so important?

After reading this article, I can see the benefits of password hashing as a second layer of defence, in the event of an intruder gaining access to a password database. What I still don't understand is ...
21
votes
5answers
1k 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. ...
15
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2answers
1k views

Are there some good papers (or discussions) on using Markov chains or Hidden Markov Models for password auditing/cracking?

As a programmer and language enthusiast I've been very interested in Markov chains for some time. Considering the influence of natural language on password and passphrase selection (by humans of ...
13
votes
3answers
2k views

Is it safe to generate passwords online?

I usually generate strong passwords using various online tools. Some time ago I mentioned it to a friend of mine and he was shocked that I do such dangerous thing. Is it really so unsafe to generate ...
10
votes
2answers
918 views

Plain Text Password Reset Vulnerability

If I receive an email with a plain text generated password (in response to a password reset request), is this a vulnerability? The password expires after one use, in other words the user has to change ...
8
votes
2answers
658 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
2answers
2k views

Considering that SRP is better than SSH and Basic Auth, how can it be implemented in a website?

SRP is short for Secure Remote Password protocol, and provides a better way for passwords to be sent over the internet. I've read the information at it's Stanford University home page, the Wiki ...
5
votes
3answers
228 views

Forgot password and revealing whether account exists

So when you hit that forgot password link and enter your email address, it seems that sites (and other programmers I've spoken to) are one of either two mindsets; Notify the user whether or not the ...
5
votes
5answers
5k 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 ...
4
votes
8answers
629 views

Does it take longer to brute force a password starting with z than one starting with a?

I was wondering about the following: If someone tries to get my password with Brute Force, will a password starting with "a" guessed faster than one starting with "z" ? In this case assume the ...
4
votes
1answer
118 views

How to help users manage password portfolios based on risks of compromise?

A framework for modeling password management risks and costs, and the beginnings of a good strategy for users to help them manage passwords for their often large portfolios of accounts is outlined in ...
4
votes
4answers
1k views

Store a password to avoid user interaction

I am creating a windows service that sends email to a user. It uses a Gmail account to send the email, so it needs a password to access the account. It also needs to do this automatically, without ...
3
votes
1answer
278 views

Security of Windows Screen Saver Password

How secure is the Windows screensaver password? Seeing that screen saver passwords are used in the corporate world, is there any way of bypassing the screen saver after it is already running? Could a ...
33
votes
3answers
5k views

Is using the username encrypted with the password as key a good password storage scheme?

On web applications I build I don't hash the passwords. Instead I symmetrically encrypt the username using the user's password and store the result in the password field. I use RijndaelManaged on ...
18
votes
8answers
3k views

Why should I hash passwords?

I've read that every good web application should hash passwords. I found many articles about hashing. So I started implementing hashing on my website and then I asked myself why should I do it? When a ...
17
votes
6answers
2k views

What does “random” mean in the context of password creation?

Disclaimer: as you will see from my question I'm a total outsider in this subject, just very curious. I was wondering how easy it would be to crack a password-protected RAR5 file, and I found many ...
17
votes
7answers
2k views

Taking password letters not whole one, is this secure? [duplicate]

I found a site which is taking password letters from their users not the whole password. Is this secure? Or do they have saved password as salted hash (MD5)?
13
votes
3answers
2k views

What is a good enough salt for a SaltedHash?

Since I'm hashing all passwords with each their own salt, is there a benefit to the salt being really random, or would an incremental counter or a guid be good enough? Also, is there a benefit of ...
9
votes
4answers
785 views

Password security

I was requested at the login page of a website to first change my password. After typing in a new password, the web page told me the new password did not differ enough from the previous one. Does this ...
8
votes
8answers
1k views

Sequential password updates

Let's say I have a reasonable KDF, and that I make users change their passwords periodically and keep some old password hashes to prevent password reuse. What's to stop the user from changing the ...
8
votes
1answer
555 views

Protecting emails in your database

It's common to encrypt passwords in the database, but I'm wondering what solutions are out there to protect emails in your database. Not just from hacking, but from disgruntled employees or engineers ...
7
votes
2answers
251 views

Does password-hashing “busy-work” need to be cryptographically secure

All modern password hashing schemes are deliberately designed to include a huge amount of "busy-work", to limit the speed with which an attacker would be able to conduct password hashing attempts. ...
7
votes
1answer
4k views

Does NIST really recommend PBKDF2 for password hashing?

We hesitated between BCrypt and PBKDF2 for password hashing. In many forums and blogs people say something like "In their Special Publication SP 800-132 NIST basically recommends using PBKDF2 for ...
6
votes
4answers
6k views

Are the iPhone “connect the dots” passwords secure?

A popular way to login to iPhones and other phones is to use a "connect the dots" password. For those unfamiliar, it looks something like this: Is this kind of passwords secure from brute force ...
5
votes
2answers
1k views

Web & insecure HTTP - Using RSA for encrypting passwords on the client side

I used client side password hashing in my register and login project. Its purpose is to prevent passive adversaries/eavesdroppers from discovering users' plaintext passwords when HTTP requests are in ...
4
votes
1answer
28k views

How long to brute-force WPA password?

Bob has a password (for his WPA encrypted wifi) which is 8 characters, all lowercase, and not a dictionary word. Eve lives next door to Bob and wants to illegally hack his WPA. The number of ...
2
votes
2answers
1k views

Is the following password-generator secure?

i use the following password-generator (python) and would like to ask if the generated passwords (usually 32 characters and more) are random enough. def pwgen(l=32): from random import Random ...
1
vote
1answer
225 views

Requiring a pin instead of password for websites?

Curious if this could be a good alternative to passwords. On a website, user can choose to use a pin instead of password. If she does elect to do this (given option) from then on, her account asks for ...
0
votes
4answers
362 views

How long does a passphrase have to be to be as secure as a random collection of letters, digits, punctuation, etc.?

If one uses a passphrase which is grammatical, such as "I put my keys under the doormat because they're safe there."... how many words (on average) must it contain to be as secure as a password with ~ ...
12
votes
5answers
870 views

Should passwords be truly random?

When generating a password, should it be "truly random" or should I make it a little less random by enforcing some rules? If a password is generated at random, it could come out all-lowercase letters ...
11
votes
4answers
1k views

Does it indicate a bad password system to disallow certain characters in passwords?

When creating an account to the game League of Legends, the user's password must comply to a few rules. The one I'm concerned about is the "Must not contain slashes or spaces" one. The others are ...
11
votes
2answers
3k views

Benefits and drawbacks of giving an Administrator two accounts for elevated rights and another for daily use, such as email

Microsoft has long promoted the need to separate administrative accounts from regular use accounts, as shown with this guidance MSFT even went to far as create ADMINSDUser rights to put ...
8
votes
4answers
2k views

Hacking computers, scifi or reality

I was watching The Girl with the Dragon Tattoo, and this female hacker was really good at hacking. My question is, how is it possible for her to crack passwords besides the brute force approach? I ...
8
votes
5answers
452 views

Is there any added security benefit to username complexity requirements?

I've come across several sites lately that have complexity requirements for usernames like "must be 8 characters long and contain at least 2 numbers". Is there any real added benefit to this from a ...
8
votes
4answers
2k views

How to protect ftp account information in the source code of a program

I wrote a game which stores high score information on an ftp server. In the the source code I need to write out the ftp link with the account name and password in it. For example: url = new ...
7
votes
8answers
2k views

Does truncating the cryptographic hash make it impossible to crack?

I store password hashes in their full value for example, $h = sha256('foo') outputs 64 characters: 2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae I store that directly in the ...
5
votes
2answers
241 views

Does adding a non-entropic part to a password makes it less secure?

Suppose I'm encrypting a file via AES using a password of my choice, or creating a TrueCrypt volume using a password and no keyfiles. Which of the following two passwords would be more secure: ...
5
votes
1answer
1k views

Can a Bitlocker To Go user pin be brute forced?

I have a external hard disk and protected a partition on it with Bitlocker To Go. I printed the recovery code but I lost it. I can't remember the user PIN either. If I could only know the first ...
5
votes
3answers
380 views

What steps can you take to make offline cracking of SRP harder?

In the aftermath of the Blizzard hack, what steps can I take to make offline cracking of SRP more difficult? My question assumes that your database is already gone and that you implemented SRP more ...
4
votes
5answers
271 views

How many combinations does a specific password policy allow?

Recently I was arguing about password policies. Assume you have a policy which requires 10 characters and additionally at least one letter, one number and one special character. My companion was ...
4
votes
5answers
866 views

Use the hash of the password to encrypted password

I have a app which transmit the password in clear text. I was planning to use the hash of the password (SHA-512) as the key for encrypting the plain text password. Then send the encrypted text to the ...
4
votes
2answers
380 views

How can I create a secure password?

I know the standard tricks, create a long password, numbers, symbols, capital letters, etc. My questions is how do I judge password security. I heard different tricks to make secure passwords. For ...
3
votes
2answers
231 views

How does my bank knows my second and forth chars of my password [duplicate]

I see that the new login mechanism used by some banks in UK and also used by visa debit authentication is to ask for three random characters from your password at login (for example second, ninth and ...
2
votes
2answers
146 views

What is the evaluation criteria that a site uses for a password as strong , moderate or less secure

I have been in kind of jinx as to how a website decides on which password is highly vulnerable , strong etc . Lately my yahoo account was told to change password which I am using for long time as the ...
2
votes
2answers
3k views

Is user password in ubuntu 13.04 in plain text?

Is it stored in plain text or not? Where can I find the file that contains the username and password for my accounts in Ubuntu 13.04?
2
votes
5answers
633 views

Does shuffling a hashed password increase its security?

I am making a web app and I'm now stuck on making the login secure. I'm thinking of adding a salt to a user-inputted password and then hash it. (md5 or sha for example) and then I will reshuffle the ...
2
votes
3answers
2k views

Recompute Rainbow table with salt?

So, as I understand it, you prepend a password with salt before you hash it so that the resulting hash can't be used with a rainbow table to find the original password, as you could if the password ...
1
vote
3answers
301 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 ...
1
vote
1answer
5k views

John the ripper passwd file format with salt not working

I'm trying test password strength in one of our e-commerce sites. I'm using john the ripper to brute-force a password file. The algorithm used by PHP is: $hash = md5($salt . $pass) No other ...
1
vote
1answer
267 views

Securing communication

The problem: I have an open-source client (a Firefox add-on written in JavaScript) and a server containing somewhat sensible user information: username and user history (all from YouTube). The client ...