Linked Questions

2
votes
1answer
363 views

Why people say that salt helps to prevent rainbow table attack? [duplicate]

I am using some frameworks that store salts inside databases. For example this article shows how Devise stores salt together with the user information. My question is why do people say that salts ...
893
votes
13answers
281k views

How to securely hash passwords?

If I hash passwords before storing them in my database, is that sufficient to prevent them being recovered by anyone? I should point out that this relates only to retrieval directly from the database,...
562
votes
7answers
184k views

How to store salt?

If you expect to store user password securely, you need to do at least the following: $pwd=hash(hash($password) + salt) Then, you store $pwd in your system instead of the real password. I have seen ...
271
votes
11answers
74k views

Why shouldn't we roll our own?

Why shouldn't we create our own security schemes? I see a lot of questions around here about custom crypto and custom security mechanisms, especially around password hashing. With that in mind, I'm ...
254
votes
7answers
100k views

Password Hashing: add salt + pepper or is salt enough?

Please Note: I'm aware that the proper method for secure password storage hashing is either scrypt or bcrypt. This question isn't for implementation in actual software, it's for my own understanding. ...
158
votes
3answers
79k views

What are rainbow tables and how are they used?

Where can I find one? Is there a pot of gold at the end? How do I protect against them? From the Area51 proposal This question was IT Security Question of the Week. Read the Sep 09, 2011 blog ...
24
votes
5answers
3k views

When hashing passwords, is it ok to use the hashed password as the salt?

I don't like this idea. But I can not come up with a technical argument against it. Can somebody explain it to me? The basic idea is: $passwd = 'foo'; $salt = hash($passwd); $finalHash = hash($passwd ...
25
votes
5answers
11k views

What's the practical limit for rainbow-table based bruteforce?

Say we have a hash of a password. The password can be considered to be made of of totally random characters and has a fixed length of N. The hash is SHA1(password+salt), where the salt is of length M. ...
3
votes
3answers
5k views

Recompute Rainbow table with salt?

So, as I understand it, you prepend a password with salt before you hash it so that the resulting hash can't be used with a rainbow table to find the original password, as you could if the password ...
3
votes
4answers
834 views

When salting and hashing passwords, any advantage to including password length?

In this answer, Gilles says (emphasis mine): There's no need to hide the salt from the attacker: it needs to be unique (and not derived from the password) but it doesn't need to be more secret than ...