Linked Questions

570
votes
21answers
113k views

XKCD #936: Short complex password, or long dictionary passphrase?

How accurate is this XKCD comic from August 10, 2011? I've always been an advocate of long rather than complex passwords, but most security people (at least the ones that I've talked to) are ...
292
votes
11answers
52k 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 ...
199
votes
6answers
26k 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 ...
280
votes
4answers
83k views

Do any security experts recommend bcrypt for password storage?

On the surface bcrypt, an 11 year old security algorithm designed for hashing passwords by Niels Provos and David Mazieres, which is based on the initialization function used in the NIST approved ...
74
votes
8answers
8k views

How would one crack a weak but unknown encryption protocol?

I was reading this interesting question: Is my developer's home-brew password security right or wrong, and why? It shows a weak home-brew algorithm developed by "Dave", and the answers discuss ...
32
votes
8answers
3k views

Why improvising your own Hash function out of existing hash functions is so bad

I'm afraid I'll have tomatoes thrown at me for asking this old question, but here goes. After reading that cooking up your own password hash out of existing hashing functions is dangerous over and ...
30
votes
4answers
36k views

Is Telegram secure?

There is a new WhatsApp-killer application called Telegram. They said that it's open source and that it has a more secure encryption. But they store all the messages in their servers and WhatsApp ...
20
votes
5answers
4k 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. ...
12
votes
6answers
2k views

Do salts have to be random, or just unique and unknown?

First of all, my motive is to avoid storing the salt in the database as plain text. As far as this question is concerned, the salt is not stored in the database. After discussion in comments and in ...
8
votes
4answers
540 views

How to evaluate the strength of a hashing algorithm?

At work the hashing algorithm we use for passwords appears to be bespoke. Obviously that's a pretty bad idea, but the management don't seem bothered. The algorithm always produces 20 character long ...
4
votes
5answers
628 views

Use the hash of the password to encrypted password

I have a app which transmit the password in clear text. I was planning to use the hash of the password (SHA-512) as the key for encrypting the plain text password. Then send the encrypted text to the ...
3
votes
5answers
3k views

Password reset links: random value or authenticated message?

Which is better? Create tamper-proof encrypted password reset token which contains the user id and the expiration time within the encrypted token. Generate a random token and store it in the ...
3
votes
3answers
3k views

Email hacking myth

I never believed that some one can actually hack an email that easy. If someone hacks an email it means he actually hacked the server and he will gain access to many emails not to mine only. Anyway ...
3
votes
3answers
1k views

How about preventing CSRF this way?

According to Cross-Site Request Forgery (CSRF) Prevention Cheat Sheet , the recommended solution to protect web site from CSRF attacking is to implement Synchronizer Token Pattern. And This requires ...
7
votes
3answers
607 views

What can a web application developer do to protect user information from powerful adversaries like the NSA or China

Some well funded intelligence services with potentially untrustworthy employees intercept and store encrypted data for years, in hopes of cracking it with future technology. What can I do to make this ...

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