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

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4
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4answers
513 views

Is it secure to use similar password over different accounts?

I have a strong password which is a long, unfamiliar word phrase. I would like make other account use a password with similar level of complexity but I don't like to remember so many password over ...
3
votes
7answers
3k 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
625 views

Cracking passwords after a pattern with John

So I am trying to find out how easy it is to crack a password using some great Linux tools. We all know about John as a password cracker and how great it is. But how about specifying a pattern. ...
0
votes
4answers
1k views

Is it bad practice to use the same password on different sites?

Is it considered bad practice to use the same password on separate sites, if so why? Even if the passwords to a site are compromised the attacker still doesn't know the user names or sites the same ...
130
votes
16answers
17k views

Is the BBC’s advice on choosing a password sensible?

In this article on the BBC’s website they offer advice on how to develop a password. The steps are as follows. Step 1: Choose an artist (a recording artist I presume) Lets choose as an example ...
31
votes
6answers
10k views

Length of passwords that are rainbow table safe

With large computing power (like what you can get in the Amazon cloud for example) you can generate huge rainbow tables for passwords. There also seems to be some large rainbow tables reachable that ...
41
votes
7answers
10k views

Why isn't open WiFi encrypted?

As far as I understand, WiFi networks that require no password send traffic through the air unencrypted. Those that require a password encrypt each connection uniquely, even if they're all using the ...
39
votes
3answers
4k views

Security Review - password_hash implementation for PHP

I'm currently working on a "helper function" for PHP's core to make password hashing more secure and easier for the majority of developers. Basically, the goal is to make it so easy, that it's harder ...
29
votes
4answers
13k 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 ...
8
votes
6answers
32k views

Modern high quality password dictionary

Has anyone come across any good password dictionary lately? Some of the lists I found dated back to 90's! Some are simply too big that I doubt their quality. There appears to be some work by someone ...
72
votes
8answers
9k views

Convincing my manager to use salts

My manager says we don't need to salt our passwords because people are not likely to use the same password because they all have different native languages, in addition to the websites they are active ...
50
votes
10answers
11k views

Why does the user pick the password?

Almost every web service I can imagine has the user pick the password. Why is this? Couldn't the system choose a better password? It doesn't have to be some complicated mess; see ...
43
votes
11answers
39k views

Are password-protected ZIP files secure?

Following my answer. If I can list contents of password-protected ZIP file, check the file types of each stored file and even replace it with another one, without actually knowing the password, then ...
24
votes
10answers
5k views

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 ...
25
votes
2answers
18k 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 ...
40
votes
7answers
3k views

“Real” Salt and “Fake” Salt

During a Q&A period at DEFCON this year, one member of the audience mentioned that we're using "fake salt" when concatenating a random value and a password before hashing. He defined "real salt" ...
21
votes
2answers
1k views

Can client-side hashing reduce the denial-of-service risk with slow hashes?

When storing user's passwords that you need to verify against (but not use as plaintext) the current state of the art is: Hash the password Use a salt Use a slow hash function - bcrypt, scrypt, etc. ...
28
votes
7answers
3k views

What is a good way to authenticate a user to a smart phone?

What would be a good way to authenticate a user to a smart phone? By good, I mean that it is both secure, and user-friendly. Passwords don't seem to be the best fit because a password needs to be ...
71
votes
10answers
12k views

If I enter a password on the wrong site, should I consider it compromised?

I have recently started to make use of a password manager and good password practices. I have a different password for each site that I use. If I accidentally use the password from another site when ...
27
votes
4answers
3k views

Is it safe to store a password hash history for preventing user to keep same password repeatedly in some cases?

I am developing an application in PHP and it uses bcrypt encryption to store passwords. I want to keep the history of hashes whenever the user changes the password. By doing this I want to stop the ...
25
votes
1answer
2k views

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 ...
10
votes
4answers
7k views

HTTP Basic auth password storage more secure than Digest auth

If you are using SSL already, it appears Basic auth is the way to go since you can perform bcrypt with the password when you store it in the database, where as Digest auth only allows md5. As we know, ...
28
votes
3answers
4k views

MD5 collision attacks: are they relevant in password hashing?

DISCLAIMER: This is not an endorsement of MD5 as a password hashing function. I know about parallelization, GPUs, and dedicated password hashing functions like bcrypt and scrypt. With that out of ...
27
votes
6answers
10k 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 ...
13
votes
3answers
759 views

How to manage team passwords?

How do most teams handle the storage of passwords, in particular the required changes when team members leave ? Right now, we use a centrally stored encrypted file but the thought of changing 100's ...
33
votes
4answers
2k views

If email is insecure, why do we use it for password resets?

I found myself telling a coworker today "Email is insecure, that's why we developed our secure report application." But then it struck me, Why is email considered insecure? If it is so insecure, why ...
31
votes
6answers
3k views

Does verifying identity by positions in passwords mean passwords are stored unhashed? [duplicate]

If authentication occurs by asking the user for the characters at certain positions in the password (such as: give the 3rd and 7th character in the password), does this imply that passwords are stored ...
16
votes
2answers
4k views

What's wrong with storing private keys in the cloud?

I know this sounds like a dumb question, but whats wrong with it? Assuming that all private data is encrypted (by the client) using PBE AES256, then is this scheme more vulerable than storing keys on ...
16
votes
5answers
3k views

The AES Crypt implementation hashes a password 8192 times to generate the key. Is this necessary?

I'm considering encrypting some small files (hundreds of kb apiece) using the AES Crypt reference implementation. Looking at the source, it seems that the encryption key is derived from the IV and the ...
12
votes
3answers
568 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 ...
4
votes
11answers
5k views

Definitely safest password storage scheme?

I already asked this on StackOverflow but I was suggested this would be a better suited place and I found no way to "move" the question so I have to copy it. Believe, I know, there are hundreds ...
26
votes
12answers
7k 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 ...
22
votes
4answers
8k 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 ...
15
votes
4answers
1k views

How are browser saved passwords vulnerable?

Most browsers offer to save the password after entering it on many logon pages. What types of vulnerabilities are there for such saved passwords. I'm interested in what ways malware on web pages ...
12
votes
7answers
1k views

Aren't password managers still incredibly risky?

I understand the utility in having one application remember a bunch of long, randomized passwords, but all you'd need is one well-placed phishing scam or a keylogger and they get all the keys to the ...
9
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 ...
3
votes
1answer
608 views

Perfectly Robust Hashing Scheme, or Completely Over-Engineered?

This is going to get long, so prepare. Basis of the question is, Do all these steps improve security, or am I completely overthinking the problem? Are my assumptions/thought process valid? We all ...
22
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
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
votes
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.
19
votes
2answers
6k 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 ...
14
votes
2answers
1k views

Password and Generated number - How does it work?

In my company, they don't allow accessing the company email or servers from outside the company network. To access the email from outside the network, you have to use: Username, password and a number ...
48
votes
1answer
3k views

What's the risk if I accidently type my password into a username field (Windows logon)?

I'm used to logging into my personal Mac which is a password-only field (like waking from sleep mode). Sometimes I have to use a Windows network on which I have an account, but of course I have to ...
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 ...
10
votes
1answer
408 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 ...
8
votes
3answers
655 views

Can cloud based password managing services be trusted?

I'm a big time user of cloud based password managing services like LastPass. But in the light of recent revelations like various government backdoors in popular sites, programs like prism, etc. I'm ...
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
660 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 ...
27
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. ...