2
votes
1answer
142 views

Hashing passwords

The common way to store passwords in web applications is this form: $$hash(password||salt)$$ Does it make sense to store them in the following form instead:? ...
3
votes
2answers
196 views

Using PBKDF2 twice with different argument order

I'm pretty sure this is a really bad approach (in theory), but one of my clients is doing this and I was wondering… How bad it is to perform pbkdf-2 in this way (with 2000 iterations)? ...
2
votes
2answers
237 views

Could completely public passphrase hashes ever be reliably secure?

This is a hypothetical question and I only have a basic understanding of Cryptography. If one were to follow the very best cryptographic practices for storing passphrases, could it ever be possible ...
6
votes
4answers
248 views

Could a very long password theoretically eliminate the need for a slow hash?

Before I provide details, I want to clarify that I am not looking to implement this practically, but I'm only asking to get a better understanding. The way I currently understand it, we use slow ...
3
votes
1answer
476 views

estimate of time required to crack sha512crypt password with JtR + OpenCL

OK, I have a shadow file with a password that I know, it is 4 letters followed by two numbers. Using John The Ripper with OpenCL support, on a laptop with AMD Radeon Mobility graphics, how long would ...
-1
votes
2answers
177 views

What is the advantage of an attacker over breaking a 4 digits PIN?

When a hardware system is protected by a 4 digits password, what is the advantage of the attacker into breaking that system? Isn't it $10*10*10*10=10^{4}$? If $\frac{1}{10^{4}}$ is the cost of such ...
3
votes
2answers
602 views

Passwords with same SALT. What does this mean?

If the same SALT is used for many passwords on a Linux server, in what way is that a security risk? Does the mean, that a user (which can change his own password) can calculate other users passwords? ...
2
votes
3answers
1k views

Dictionary attack on pass-phrases on common algorithms

I don't yet perfectly understand the difference between brute-force and dictionary attack since this differentiates one attacking the key and another attacking password: apparently attacking passwords ...