All Questions
12 questions
47
votes
2
answers
10k
views
Are there more modern password hashing methods than bcrypt and scrypt?
This question made me start thinking about password hashing again. I currently use bcrypt (specifically py-bcrypt). I've heard a lot about PBKDF2, and scrypt.
What I'm wondering is if there are any "...
- 2,928
34
votes
5
answers
5k
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 when ...
- 441
11
votes
3
answers
13k
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 ...
- 547
10
votes
2
answers
2k
views
Is there any recommended approach for "upgrading" MD5 hashes to something secure? [duplicate]
I'm currently dealing with a couple of user accounts containing MD5 hashed passwords. These accounts got migrated from an old system into our current system which uses PBKDF2 for password hashing. I ...
8
votes
3
answers
5k
views
LastPass One Time Recovery Passwords--How?
The LastPass password manager stores One Time Recovery Passwords locally in each browser you use the plugin with:
http://helpdesk.lastpass.com/account-recovery/
My question is, how can you have more ...
- 2,292
6
votes
3
answers
1k
views
Trying to understand password hashing
I am trying to get a grasp of password hashing. Back in the days it seemed so simple, just MD5(password + salt) and you are done. Then md5 was proven to have collisions so people started moving to ...
- 16.2k
4
votes
1
answer
6k
views
BCrypt vs PBKDF2-SHA256
I read that LastPass uses PBKDF2-SHA256 for storing the Master Password hash, I wonder how this compares to BCrypt and why did they chose this, as SHA256 is a quick hash (probably compensated by PKDF2?...
- 301
2
votes
1
answer
674
views
Is there any problem using empty salts with PBDKF for this purpose?
The aim is to generate a secure key for symmetric encryption.
I have a master password, from which I want to generate the key for symmetric encryption, in order to encrypt other passwords. The idea ...
- 361
1
vote
2
answers
337
views
Protecting Passwords Using Short Hash Length
Does anybody use deliberately short hash lengths for passwords to increase the chance of false positive collisions in the event of a brute force attack on the database?
When trying to decide on a ...
- 113
0
votes
1
answer
130
views
Why is "not storing data protection keys" not a popular choice?
In the NIST SP 800-132, they specified two ways to use the data protection key (DPK) that is derived from a password. One of them is to use the DPK to encrypt data, and then, if I am not mistaken, ...
- 13
0
votes
1
answer
291
views
MD5 before PBKDF2 on legacy software
I am mantaining a legacy software that uses MD5 in the following way:
The client asks for a 16 byte salt when authenticating an account.
The server generates a 16 byte salt, links it to the account ...
- 103
0
votes
0
answers
126
views
Is pass -> [via pbkdf2] -> seed -> ECDSA key pair better than pass(word) hashing?
For a web service, I am considering generating random 25-49 recovery codes as a kind of pass that can be stored in a pass manager (no usernames).
Instead of pass(word) hashing on the server, I ...
- 138