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

learn more… | top users | synonyms

23
votes
1answer
2k 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 ...
22
votes
3answers
2k 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 ...
19
votes
2answers
7k views

How big should salt be?

I will be using scrypt to store passwords in my application. As such, I'll be using SHA-256 and Salsa20 crypto primitives (with PBKDF2). Having that in mind, how big salt should I use? Should it be ...
10
votes
1answer
433 views

Is this cross-site password model secure?

I'm looking for a way of securely having passwords for different pages. Say I generate this password: ild23rfsfdfg%*#fArg34t34657%537@asd7oak2094^*q2k2k@Kk3j4tn453Q5# Then, for each site, I change ...
10
votes
4answers
1k views

Are efforts being made to bring about password standards?

Rather than adopting a universal standard, many websites develop their own guidelines for how passwords should be constructed. When you consider the number of passwords the average person today has ...
7
votes
2answers
7k views

Is it possible to speed up WPA/WPA2-PSK cracking using a rogue AP?

We know that WPA/WPA2-PSK uses a PTK (Pairwise Transient Key) for each client to encrypt the communication. This PTK is generated through the process known as 4-way handshake. As told in the related ...
6
votes
3answers
683 views

Is piping a `ssh-agent` signed message as a password secure?

There's an encrypted filesystem on a server I ssh into using public key authentication. Since a forwarded ssh-agent can deterministically sign a message (see also the ssh-agent protocol section 2.6.2),...
6
votes
7answers
5k views

How can I best manage root passwords for many servers?

Lets say I have two racks with about 40 nix servers in them. I don't want to set all of the root user passwords all the same do I? If not how do you manage and keep up with all of the passwords? Is ...
5
votes
5answers
6k 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 ...
26
votes
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. ...
18
votes
6answers
3k 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)?
15
votes
2answers
2k 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 ...
14
votes
6answers
929 views

Is there additional security value in using passwords with words or phrases in non-English languages?

I was thinking about correct horse battery staple. I am not a native English speaker. In my language, the above could be written as: vqrno kon bateriq telbod OR вярно кон батерия телбод. Keep in ...
13
votes
3answers
3k 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
1k 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
3answers
479 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 ...
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 ...
4
votes
1answer
122 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
3answers
4k views

Email hacking myth

I never believed that some one can actually hack an email that easy. If someone hacks an email it means he actually hacked the server and he will gain access to many emails not to mine only. Anyway ...
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
2answers
1k views

Pattern based password cracking

I need to select a project for this semester. I'm a second year uni student in Ethical Hacking and Countermeasures. My idea was to see if using some kind of pattern based password cracking can be more ...
3
votes
1answer
314 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 ...
32
votes
3answers
6k 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 ...
15
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 ...
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 ...
10
votes
2answers
1k views

My bank makes me enter my password using the mouse. What's up with that?

Internet banking login process for Westpac requires user to enter the password using the mouse. It's annoying, what's up with that? Is it just to try and stop keyloggers on public computers or is ...
9
votes
4answers
832 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
2k 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 ...
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
2answers
264 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. ...
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
1answer
30k 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 ...
5
votes
2answers
2k 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
2answers
246 views

How do I protect my passwords from WebBrowserPassView?

I just got shocked with what can be achieved with WebBrowserPassView. It basically shows every password I've saved in my browser (Chrome). I guess other users on my PC could get my passwords that ...
4
votes
2answers
180 views

Similarity comparisons with hashed passwords possible?

At a company I worked at, I had to change my password every 90 days and I could only reuse a password after 8 iterations. This no-reusal included passwords being too similar to the old one, e.g. when ...
3
votes
1answer
497 views

Non English password dictionaries [closed]

What is a good resource for wordlists used in auditing passwords in non english languages. I have extensive wordlists in English ranging to several GB's, but can't find similar resources for other ...
2
votes
2answers
141 views

Single-use password as the default authentication method?

The crazy password requirements (joke1, joke2) lead me to a situation where there is no way for me to memorize the passwords to the several sites that make those requirements. The result is that ...
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 ...
0
votes
4answers
418 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 ~ ...
0
votes
1answer
265 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 ...
-1
votes
1answer
149 views

client side and server side hash password [duplicate]

Another question about client or server side password hashing, I know. After reading many other post about this topic I'm still a little confused and not completely sure what is the best, because I ...
13
votes
5answers
893 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 ...
12
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 ...
11
votes
4answers
852 views

Should I obfuscate passwords before hashing? Should I pre-hash them on the client? What about salts?

For fun, and in my spare time I'm creating a simple CMS for my own purposes (with hopes to release for wider use... later), using PHP. I'm currently working on the login scheme now, and have a few ...
9
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 can'...
9
votes
5answers
491 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
1answer
182 views

Does eliminating the possibility of repeat words make Diceware passwords significantly less secure?

I read about Diceware passphrases and whipped up a little program to generate passwords in that style. I do this by taking the list of dictionary words to create passwords and "ordering them" by 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 URL("ftp:...