Specific to the security of passwords: hashing, entropy, cracking, resets, lockouts, etc.
12
votes
5answers
727 views
Is it legal to log passwords from failed logins?
Is it legal to store/log mistyped passwords?
How many of you have seen this happen in a log file or DB?
11
votes
4answers
3k 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 ...
10
votes
2answers
981 views
Tamper-proof BIOS password & settings storage with Trusted Platform Module?
In the olden days, one could trivially bypass BIOS passwords on most PCs by removing the BIOS battery and clearing the CMOS.
My question is: On modern PCs equipped with a Trusted Platform Module ...
7
votes
5answers
2k views
Email forgotten password or send reset link, both just as insecure?
I originally posted this as a reply here in this thread but didn't get much feedback on it, and now I'm curious as to what others think is the best approach, or if there is any difference between the ...
4
votes
2answers
1k views
Reference implementation of C# password hashing and verification
Does anyone have a reference implementation (ideally 3rd party certified, or government approved) way one-way hash a password for C# and or Java?
Ideally,I'd like to see something that includes a ...
9
votes
2answers
553 views
How secure is asking for specific characters of passwords instead of the entire thing?
In some password-authenticated sites, you are asked to enter a random selection of specific characters from your password rather than the whole word/phrase. For example, it might say 'Enter the 1st, ...
5
votes
4answers
388 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 ...
2
votes
1answer
533 views
Security of bcrypt/sha256 key used with AES to encrypt a file
I'm looking to encrypt files using secure hashing and encryption algorithms in Python. Having used bcrypt in the past, I decided to use it for my passphrase calculator, then pass the output through ...
215
votes
13answers
37k 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 ...
41
votes
5answers
11k views
Certificate based authentication vs Username and Password authentication
What are the advantages and drawbacks of the certificate based authentication over username and password authentication?
I know some, but I would appreciate a structured and detailed answer.
UPDATE
...
30
votes
3answers
1k 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 ...
28
votes
16answers
4k views
Why do people think that this is bad way to hash passwords?
Well, please tell me, what's wrong with this code:
$password = "hello";
$password = md5($password);
for($i=1;$i<20;$i++){
$password = md5($password);
}
It's exactly the same as this one:
...
15
votes
9answers
2k 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 ...
27
votes
9answers
2k views
Isn't OAuth, OpenID, Facebook Connect, and others crazy from a security standpoint?
I work with APIs all the time and I work with web developers who insist that OAuth, OpenID, etc are far superior than a home-brew method. Every site seems to be using these as well now for ease of use ...
15
votes
3answers
2k 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 ...
12
votes
3answers
1k views
Recommended policy on password complexity
Is there any research on how how a password complexity policy can increase or decrease the quality of passwords?
If you don't have any requirements on the password then probably 90% of users will use ...
3
votes
11answers
3k 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 ...
19
votes
6answers
924 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 ...
14
votes
5answers
1k views
The aescrypt 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 aescrypt reference implementation. Looking at the source, it seems that the encryption key is derived from the IV and the ...
11
votes
4answers
1k views
Looking for example of well-known app using unsalted hashes
Does anyone know of a well-known application that still uses unsalted hashes for password storage? I'm looking for an example for an upcoming lecture on Rainbow Tables, and I think it would add ...
26
votes
5answers
2k views
Are GUIDs safe for one-time tokens?
I see a lot of sites use GUIDs for password resets, unsubscribe requests and other forms of unique identification.
Presumably they are appealing because they are easy to generate, unique, ...
12
votes
6answers
3k 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 ...
11
votes
4answers
753 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 ...
10
votes
8answers
684 views
Password management/synchronization?
Is there a good enough service I could run on my own home (Linux) server that I could use for storing/accessing/synchronizing passwords so they could be available for me from multiple ...
7
votes
6answers
1k views
Is denying login after incorrect attempts ineffective?
Generally denying logon attempts after X amounts of incorrect attempts for Y amount of tries is a very basic way to prevent bruteforce attempts or malicous logon attempts.
Yet, surely doing this is ...
18
votes
5answers
1k views
How valuable is secrecy of an algorithm?
On the surface, the inadvisability of security through obscurity is directly at odds with the concept of shared secrets (i.e. "passwords"). Which is to say: if secrecy around passwords is valuable, ...
18
votes
5answers
766 views
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 ...
11
votes
2answers
2k views
What are the most common password salting methods?
I learned that the Sun guys used the login name as salt for password hashing. Is this a common approach?
What are the most common salt values?
8
votes
1answer
2k views
Can a dictionary attack crack a Diceware passphrase?
Everyone knows the words used in Diceware passwords (all 6^5 = 7776 words are published) -- they're all common words.
Everyone seems to know that we're not supposed to use dictionary words for ...
8
votes
4answers
971 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 ...
14
votes
2answers
573 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 ...
5
votes
2answers
3k 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 ...
3
votes
2answers
331 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 ...
3
votes
3answers
672 views
Calculating complex password entropy?
Whenever I look at password entropy, the only equation I ever see is E = log2(R)*L, or alternatively E = log2(R^L), where E is password entropy, R is the range of available characters, and L is the ...
25
votes
1answer
1k 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 ...
18
votes
5answers
1k views
Is my bank storing my password in plain text?
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?
14
votes
4answers
782 views
What to transfer? Password or its hash?
Let's say in my database I store passwords hashed with salt with a fairly expensive hash (scrypt, 1000 rounds of SHA2, whatever).
Upon login, what should I transfer over the network and why? Password ...
13
votes
6answers
689 views
Appropriate password requirements for a login (OpenID) service/provider/delegate/thing
This is with regards* to Stack Exchange's upcoming OpenID provider (and in particular, discussion about password requirements).
Currently, password requirements are:
Must contain 3 of: lower case ...
10
votes
4answers
2k views
https security - should password be hashed server-side or client-side?
I am building a web application which requires users to login. All communication goes through https. I am using bcrypt to hash passwords.
I am facing a dilemma - I used to think it is safer to make a ...
7
votes
1answer
227 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 ...
6
votes
4answers
3k 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
1k 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 ...
5
votes
2answers
607 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 ...
2
votes
6answers
620 views
“Double hashing” with 2 different hash functions
Is doing something like this
sha256(sha512(password+salt))
Less secure then just doing
sha256(password+salt)
I've heard it will increase collision chances.
I can think of 3 reasons to do this
...
19
votes
3answers
831 views
Am I wrong to believe that passwords should never be recoverable (one way hash)?
I recently forgot my password for our cable provider online account, only to discover that they sent it to us via plain text in an email. I quickly sent an email to customer support asking them if ...
17
votes
5answers
689 views
Is there any legal reason to save a cleartext password?
I called customer service of a well known company and discovered that the operator had the ability to view my website password in clear text on her screen.
I asked her about this and she defended the ...
8
votes
2answers
514 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
8answers
870 views
Why do we authenticate by prompting a user to enter both username and password? Does prompting the password only suffice?
I don't know why do we authenticate by prompting the user to enter both username and password.
In my mental model, prompting password only suffices.
The reason is as follows:
Assume there are x ...
6
votes
4answers
239 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 ...
4
votes
3answers
465 views
Can password-protected zip files be broken without brute force?
You have a zip file that you created with 7z to password-protect it with AES 128. Can a smart adversary extract the data only through brute force, or is the file vulnerable to other attacks - such as, ...
