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

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2answers
74 views

Creating secure passwords [duplicate]

I have been tasked with writing a random password generator to be used on a series of throw away accounts. In this scenario, the accounts need to be very secure and will be deleted after a single day ...
30
votes
4answers
15k 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 ...
3
votes
4answers
341 views

Help generating wordlist using crunch

I need to configure crunch so that it produces a wordlist with the following set of rules: Exactly 10 characters long Contains exactly 4 letters, which have to be a-f (all lowercase) Contains ...
0
votes
3answers
186 views

How secure would this method be considered for password storage

Ok I am currently storing the passwords in most secure way I could think of. With use of Encryption and Hash. The passwords are first generated by user as plain-text with minimum length of 6 ...
3
votes
0answers
56 views

Is it possible to use parallelism when computing a key derivation function for a single password/key?

Suppose I have an AES-256 encrypted file, and I want to derive the key using PBKDF2 and a given salt with a large number of rounds (say 1 million), but I'm limited by user tolerance for UI lag when ...
-10
votes
6answers
150 views

Is the password FFFFFggggg&&&&&22222 safe from being guessed? [closed]

It is 20 characters long, mixes alphanumeric and special symbols. It is one among ** 20.
64
votes
13answers
9k views

Should I allow browsers to remember my passwords and synchronize them?

I wonder, how wise is it to allow Chrome and Firefox to a) remember the passwords b) synchronize them? My gut tells me that if it's not man in the middle who can intercept them, but Google and Mozilla ...
1
vote
2answers
278 views

Do WiFi passwords remain accessible significantly after logging in?

"... they'll go to the taskbar and look at the properties of the WiFi router to get the password." is a quote from another question on this site, and is in the context of WiFi passwords. The ...
139
votes
5answers
10k views

What to do if stuck with website that has poor security?

I have a student loan account with a company, not the biggest company but big enough to where they should have their act together. Today I couldn't remember my password to log into my account ...
8
votes
2answers
102 views

How can I enforce strong password policy with non-technical user base?

I've been using zxcvbn to enforce strong passwords for a service where break-ins would cause considerable problems. However, the service is only viable if many users sign up. We've found that users ...
3
votes
2answers
460 views

Storing a user's password in a retrievable manner

I currently store my users passwords as PBKDF2 hashes, for the authentication part of my web application. Each user also has their own private key and public key (also stored in their user profile in ...
7
votes
2answers
1k views

philosophical: restricting the password space increases security

This is more of a philosophical question. Suppose that you are trying to choose a good password for a particular online service, say your bank's e-banking service. Now the bank has some restrictions ...
9
votes
2answers
215 views

How to create dictionary to prevent weak passwords?

I've been tasked with adding a "dictionary check" against user's passwords to prevent weak passwords. Unfortunately, that is about as much guidance as I've been given and I need some help deciphering ...
8
votes
3answers
2k views

Why can't the FBI copy the contents of an iPhone they are trying to crack?

Making the news rounds now is a story about the courts ordering Apple to disable the automatic deletion of data after 10 failed password guesses. What I don't understand is, why doesn't the FBI just ...
4
votes
3answers
114 views

Is emailing a password recovery code as bad as emailing a password in plain text? [duplicate]

I am creating a mobile app where my password recovery feature involves sending a password recovery code (randomly generated string) to the user's email address. They get the code, then enters it ...
-1
votes
1answer
64 views

Do you consider PWGen safe to use?

Do you consider PWGen safe enough to use? What do you use to make truly random password. PWGen should be using "movement of your mouse" to make it really random, right?
3
votes
3answers
107 views

Is it insecure to reveal if a password is being used for another account after a set period of time?

Password reuse can be considered a pandemic of security. The obvious way to fix this is to encourage people to use password managers, but (comparatively) few people actually do. My idea is to have ...
16
votes
3answers
16k views

openssl: recover key and IV by passphrase

A large amount of files were encrypted by openssl enc -aes-256-cbc -pass pass:MYPASSWORD Openssl should derive key+IV from passphrase. I'd like to know key+IV equivalent of that MYPASSWORD. Is ...
1
vote
2answers
111 views

Pin delivery: SMS, mail, or pin mailer?

Imagine a scenario where a 4-digit pincode needs to be delivered securely to an end-user. Several possibilities exists: Pin mailer (this seems to be standard according to ISO 9564-1) SMS Email Email ...
3
votes
1answer
48 views

Membership.GeneratePassword

I am looking for a method to generate a onetime password for provisioning purposes in ASP.NET-MVC. I came across the Membership.GeneratePassword which is in the System.Web.Security namespace. Is this ...
4
votes
1answer
75 views

Wordpress.org pages refresh when logging out of Gmail

I've noticed that when I change my Gmail account by logging out of one account and then logging into another, all open Wordpress.org pages refresh. Additionally, when I recently changed a password on ...
3
votes
3answers
143 views

Prevent password reusing across different sites

I'm generally against too strict or complex rules to accept passwords (rules like "It must contain at least one upper-case character, one number and one symbol" and things like that, see also XKCD ...
4
votes
1answer
68 views

Is limiting/cutting password-length without notice insecure?

I have encountered that our linux system cuts the length of every password to a certain length, after that length every additional character seems to be ignored. Does this make our linux system more ...
3
votes
1answer
43 views

Single randomly generated passphrase for both identity and authentication

There are questions about using a password only to identify and authenticate a user, rather than an email address or username plus password: Why do we authenticate by prompting a user to enter both ...
2
votes
4answers
214 views

Are limited length passwords a security risk? [duplicate]

I found a webpage where users can be registered. However, it seems that the length of the password must be between 6 to 12 characters. Is that a security risk?
1
vote
1answer
47 views

What are the advantages of a ZKP authentication system?

So, I read somewhere that Zero Knowledge Proof based authentication is good because it makes sure that the server does not store your password and neither is your password being transmitted over the ...
17
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7answers
2k views

Are password complexity rules counterproductive?

In creating a login for this site I chose a nondictionary password that would be extremely hard to guess, but easy to remember. I was told that it did not meet complexity rules. After several ...
6
votes
4answers
394 views

How will security need to be changed if we can crack password hashes in quasi-polynomial time?

If we suppose that we have access to some form of generalized password hacking/cracking that can somehow find an n-bit password in time O(n^(log n)), is there need for alarm? This question arises ...
0
votes
0answers
15 views

Are excessively strong password requirements counter-productive? [duplicate]

Some sites have strong requirements. E.g. Your new password must: be at least 8 characters long (longer passwords are more secure) contain at least 1 uppercase character contain at least 1 ...
0
votes
1answer
23 views

Principal Password in Kerberos KDC database

Is there a way for me to merge a bank account number, fingerprint image and IMEI of a phone into a single entity that I could possibly use as a password in the Kerberos KDC to uniquely identity a ...
1
vote
2answers
63 views

How can i Identify and use hash function given enough text and their hash?

So, I have this old program currently in use, as i have access to the database i have adopted all data i need except the user passwords.. Now users will provide me with the plain text password and ...
2
votes
1answer
55 views

php's password_hash with system wide salt [duplicate]

I'm thinking about using password_hash function for generating password hashes. I have read that own salts shouldn't be generated and instead use the default one that the function generates. Own salts ...
414
votes
22answers
87k views

How does changing your password every 90 days increase security?

Where I work I'm forced to change my password every 90 days. This security measure has been in place in many organizations for as long as I can remember. Is there a specific security vulnerability ...
15
votes
3answers
11k views

Is HTTPS and Basic Authentication secure enough for banking webservices (RESTful)?

I have been reading about SSL/TLS for the last few days and looks like it has never been practically cracked. Given SSL/TLS is used for all communications between client application and the server, ...
2
votes
2answers
83 views

When is a group password for a closed circle of users acceptable?

I am developing a tool for a company, that takes some technical data and creates PDF reports. In the tool you have several text fields, which get filled by the database. If the user wants to, he can ...
32
votes
7answers
5k views

How to prevent username and password matches when changing a username?

Let's say that I have a system where one of the security requirements is preventing users from choosing a password that matches their username. Usernames are not case sensitive but the passwords are. ...
4
votes
1answer
73 views

Android auto complete and passwords

I have an Android phone and when I enter a password in a password field (bank application or other), the auto complete system proposes to complete the password. I expected password not to be saved by ...
6
votes
1answer
176 views

When I register on a website, is there a way to know whether or not the site admin will be able to see my password? [duplicate]

It seems to me that whenever I register on a website, there is absolutely no guarantee that the administrator will not be able to decrypt and view my password (if they even bother encrypting my ...
2
votes
3answers
208 views

Is it safe to generate a password for a user during sign up in a web application?

I'm working on updating a web application. It currently creates a password for a user during sign up. Is asking the user to create the password themselves safer than relying on a generated password?
9
votes
3answers
1k views

Client-side BCrypt, store salt and hash separately in MySQL database [duplicate]

I’m developing an Android app with a MySQL database for storing user login credentials. I’m using jBCrypt for hashing passwords before storing them in the database. On registration, the password is ...
0
votes
1answer
67 views

Checking a salted hash against known password?

I've created a mysql dump of my users and passwords and awked them into a presentable form: Passwords: ...
5
votes
3answers
218 views

How can I prove that my software is secure for those who are interested to install it?

I've written a password locker program for Microsoft Windows that encrypts its contents to the local machine. The only way to get the data out is with the encryption key the user knows. It uses the ...
95
votes
11answers
13k views

How critical is it to keep your password length secret?

Is keeping your password length secret critical to security? Does someone knowing that you have a password length of say 17 make the password drastically easier to brute force?
3
votes
1answer
87 views

Unable to completely enforce password policy

PCI DSS has a few requirements regarding the password policy (like remember last four passwords, change password every 90 days, use at least seven numeric and alphabetic characters and more). These ...
157
votes
10answers
34k views

Is “the oft-cited XKCD scheme […] no longer good advice”?

I was stumbling around and happened onto this essay by Bruce Schneier claiming that the XKCD password scheme was effectively dead. Modern password crackers combine different words from their ...
0
votes
1answer
73 views

Is there a way to securely check if a password is one of the most used ones?

So lets's say that a user wants to register to some website. For whatever reason, I want to not allow that password if it is one of the top 100 passwords used on my site (So I'm not checking against ...
9
votes
3answers
2k views

How often should passwords change?

I'm asking two very related questions As an admin what policies should be enforced regarding the frequency of password changing? I have an idea that users should be forced to change their ...
8
votes
5answers
3k views

Is forcing users to change passwords useful?

In many places, there's a policy that force the user changing it's password once a few months. The logic here is, that even if the password have leaked somehow, it'll be abused only for a relatively ...
290
votes
8answers
52k views

How to store salt?

Nowadays, if we expect to store user password securely, we need at least do the following thing $pwd=hash(hash($password) + salt) then store $pwd in your system instead of the real password. I have ...
2
votes
2answers
49 views

Would a multilingual Diceware password be more secure than a monolingual one? [duplicate]

I've been reading up on Diceware recently, and I'm wondering if using a mix of languages would make it even more secure. On the face of it, it would force a potential attacker to consider an even ...