A salt is a random addition to a password to make the hashed password less susceptible to a lookup table attack
-1
votes
3answers
120 views
Salting in encryption (rather than hashing)
I am aware of the benefits of adding a salt to values that are hashed using a one-way function. Is adding a salt to a value that is being encrypted (using symmetric encryption) considered to be good ...
22
votes
7answers
3k views
Is salting a hash really as secure as common knowledge implies?
(I did search on this topic, but I found no complete question/answer that addressed it, or even good portions of questions that might be relevant.)
I'm implementing a salt function for user passwords ...
2
votes
4answers
165 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 ...
2
votes
0answers
53 views
Knowing a valid salted hash for an unknown secret, is it possible to compute another valid hash? [migrated]
H(s,r)=d is a function that hashes the string s with a salt r, giving the result d.
Hashing functions are not injective, so there isn't a reverse function H'(d,r)=s.
Therefore to prove that d is a ...
0
votes
3answers
98 views
Why one time passwords using nested hash chain are not used?
I am wondering, why web sites do not use one-time passwords generated by hash chain. By that I mean that a client chooses a secret and after being salted, he applies some secure hash function F() on ...
25
votes
8answers
2k views
Why would salt not have prevented LinkedIn passwords from getting cracked?
In this interview posted on Krebs on Security, this question was asked and answered:
BK: I’ve heard people say, you know this probably would not have
happened if LinkedIn and others had salted ...
17
votes
4answers
971 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 ...
-2
votes
2answers
200 views
How to secure passwords when site is opensource [duplicate]
Possible Duplicate:
How to securely hash passwords?
How can I store passwords to have them secure? Right now the site use md5 md5, I was thinking about sha1+salt but if the source code for ...
8
votes
1answer
2k views
Wheres the salt on the openssl aes encryption?
Im interested in knowing how and where openssl inserts the generated salt on an AES encrypted data. Why? Im encrypting data in Java classes and need to guarantee that i can use openssl to decrypt them
...
4
votes
2answers
217 views
How less secure is an encryption if we know something about the original data?
I have a number of files encrypted with a key derived from a password. In line with standard practice, I use a random salt and password and do many PBKDF2 iterations to obtain an encryption key and ...
1
vote
2answers
112 views
How high is the entropy of this salt-generating code? (No code-reading actually necessary)
What is the best method?
Assumption: I have a function that generates a number of medium-high entropy bytes
Step1:
I generate 3 of these medium-high entropy bytes.
Step2:
I hash these bytes using a ...
3
votes
4answers
187 views
Is it safe to have the salt equal to IV?
If I'm using AES-256 CBC to encrypt, getting the 32 byte key using multiple iterations of the PBKDF2 function with a 16 byte salt, is it safe for me to let IV be equal to the salt?
(Edit: The salt is ...
2
votes
3answers
603 views
Can the salt for PBKDF2 be a hash of the user-entered password?
I want to derive a key from a password in a client application that will be used as a master key that decrypts a data key. As far as I understand the salt should be private knowledge. Would it be ...
2
votes
2answers
252 views
Why doesn't Microsoft implement salt on users passwords in Windows?
Pretty straightforward - So we use rainbow tables to get passwords of users out of hashes. So why won't Microsoft implement salt on the passwords in Windows to be hash(password+salt)?
Won't this ...
0
votes
0answers
34 views
Database hash for password field [duplicate]
I'm using a mysql database and am looking for a cryptographic hash method for a password with salt added to it. What would be the best hash method for this problem?
0
votes
1answer
117 views
Determine hashing algorthim only with known input and output
Given the input:
test
A system generates the following output hash:
0x001F41B6A0534D3B851D69EFE6237F550100000010D5F4FC65E64BCFDBF2590212E4411C44942C6C734C00ACFE13B958DCAB3614
I do not know ...
1
vote
1answer
189 views
I've heard that salt is not meant to be secret, but what if I made it secret? [duplicate]
Possible Duplicate:
Password Hashing add salt + pepper or is salt enough?
How to store salt?
Ok I have been studying a lot about password hashing lately. And I have a few questions. So I ...
2
votes
1answer
116 views
Can a salted hash be an effective MAC?
An HMAC is basically a "keyed hash". Only the correct message and the correct key will produce a particular hash digest efficiently.
Conceptually speaking, the same can be said for a salted hash; ...
1
vote
3answers
439 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 ...
2
votes
3answers
100 views
Clarification on an email about a security breach
I got the following email from a forum I was subscribed to:
It is our duty to inform you that there has been a security breach on
the server that Doom10 was being hosted on. It doesn't seem like ...
6
votes
2answers
707 views
With PBKDF2, what is an optimal Hash size in bytes? What about the size of the salt?
When creating a hash with PBKDF2, it allows the developer to choose the size of the hash. Is longer always better? Also, what about the size of the random salt? Should that be the same size as the ...
16
votes
4answers
524 views
In hashing, does it matter how random a salt is?
I recently had a comment made to me in an online discussion after I'd stated that randomness in a salt doesn't matter -- and I got the following response:
Salts may not have to be "secure," but ...
1
vote
2answers
448 views
should i use urandom or openssl_random_pseudo_bytes?
I am developing a site in php 5.4 and i was wondering which is better to use to gen a random salt for password security?
$salt = sha1(openssl_random_pseudo_bytes(23));
or
$seed = '';
$a = ...
9
votes
2answers
352 views
Password Salts and Randomness
Alright, so I understand that users are the kind of beasts who like to use one password and make it short and easy to remember (like "doggies"). If I understand correctly, that's one reason we use ...
15
votes
7answers
383 views
To salt, or not to salt? [duplicate]
Possible Duplicate:
Why is using salt more secure?
Why would salt not have prevented LinkedIn passwords from getting cracked?
Recently I decided that I wanted to learn more about web ...
6
votes
3answers
496 views
How to authenticate a salted password?
If only the password hash is stored and the user inputs the original password, how does the program know that it is correct? I guess it could check all the possible salts but if there are 32bit salts ...
17
votes
7answers
2k views
Why don't people hash and salt usernames before storing them
Everyone knows that if they have a system that requires a password to log in, they should be storing a hashed & salted copy of the required password, rather than the password in plaintext.
What I ...
34
votes
4answers
11k 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.
...
16
votes
5answers
400 views
Hashed password storage with random salt
Ever since I've been making sites that require a user to log in with a username and password I've always kept the passwords somewhat secure by storing them in my database hashed with a salt phrase. ...
2
votes
4answers
406 views
iOS app - hash user password in-app or on-server?
I'm working on an iOS app that will also have a web component. When a user creates an account, their password will be salted and hashed. I already have the hashing algorithm working on the web-side.
...
2
votes
1answer
170 views
Is there a better way to take advantage of current 'approved', 'proven', and memory/cpu-expensive algorithms while using salts and peppers?
I've read about the concepts presented in these two questions:
Pre-hash password before applying bcrypt to avoid restricting password length
Would it make sense to use Bcrypt and PBKDF2 together?
I ...
10
votes
3answers
456 views
Does the salt need to be unique or not predictable?
I always thought that salts is simply used to prevent rainbow tables to be used. Other have suggest they should be unique on a per account basis. Currently i have been using a config file to use as ...
5
votes
3answers
316 views
I don't see how “-salt” in the openssl command line tool enhances security at all
I do this to encrypt a single file:
openssl aes-256-cbc -a -salt -in file.txt -out file.enc
and then type in some regular plaintext password.
I do not understand how -salt enhances the security of ...
121
votes
7answers
8k 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
3answers
183 views
Password Security: Encrypting salt [duplicate]
Possible Duplicate:
Password Hashing add salt + pepper or is salt enough?
I'm new to security and trying to understand why encrypting or hiding a salt is not considered useful. I've read ...
1
vote
1answer
369 views
cracking MD5 with salt using JTR
In a legal, learning context at school, we have to understand security in Linux in the /ect/shadow file and the anaconda-ks.cfg.
These two files contains often different kind of hash and the password ...
6
votes
3answers
251 views
Is it secure to use bcrypt-generated salt in cookie to serve as token in place of a password?
I have a (hobby) web site that runs only on SSL. The site does not deal with finances, social security numbers, or anything of that level of importance. However, I'd like to secure it as much as ...
5
votes
3answers
338 views
bcrypt: random salt vs computed salt
I'm pretty new to the whole password hashing business, so I might be missing something obvious.
I was looking at the bcrypt algorithm, in particular BCrypt.Net, and I was wondering if it wouldn't be ...
4
votes
4answers
571 views
Is encrypting a salt value with a password/plaintext a viable alternative to straight up hashing?
The basic problem, as far as I can tell, is that hashing's flaw is that the password is in the hash. Asymmetric encryption's flaw is that the password is encrypted and can be reversed.
The posts ...
3
votes
3answers
486 views
optimal way to salt password?
A good way to salt password?
I have read a few answers related to salting password. But I started to get confused.
I came across few functions people used to generate salt like:
mcrypt_create_iv()
...
5
votes
2answers
255 views
PKCS#5 Salt privacy? [duplicate]
Possible Duplicate:
Password Hashing add salt + pepper or is salt enough?
In the official documentation of the PKCS5 V2.0 standard, we can read "The salt can be viewed as an index into a ...
-1
votes
1answer
184 views
Global salt vs salt-per-password [duplicate]
Possible Duplicate:
Password Hashing add salt + pepper or is salt enough?
Any risk in using the same salt for several hashes on a user?
It's known that all password hashes need to be ...
28
votes
7answers
7k views
How can crackers reconstruct 200k salted password hashes so fast?
I'm researching for a small talk about websecurity and I found one article about the formspring hack, which made me curious. They claim to have used SHA-256 + salt
We were able to immediately fix ...
15
votes
4answers
1k views
Why is using salt more secure?
Storing the hash of users' passwords, e.g. in a database, is insecure since human passwords are vulnerable to dictionary attacks. Everyone suggests that this is mitigated via the use of salts, but the ...
9
votes
2answers
2k views
What are the most common password salting methods?
I learned that the Sun guys used the login name as salt for password hashing. Is this a common approach?
What are the most common salt values?
8
votes
1answer
283 views
Any risk in using the same salt for several hashes on a user?
Right now I'm storing a salt and password_hash on the users table (pretty standard stuff).
The need arose to get a secure hash of another field for a user. Is there any risk in reusing the same salt ...
33
votes
7answers
2k views
“Real” Salt and “Fake” Salt
During a Q&A period at DEFCON this year, one member of the audience mentioned that we're using "fake salt" when concatenating a random value and a password before hashing. He defined "real salt" ...
6
votes
2answers
1k views
How big salt should be?
I will be using scrypt to store passwords in my application. As such, I'll be using SHA-256 and Salsa20 crypto primitives (with PBKDF2).
Having that in mind, how big salt should I use?
Should it be ...
8
votes
6answers
549 views
Does prepending a salt to the password instead of inserting it in the middle decrease security?
I read somewhere that adding a salt at the beginning of a password before hashing it is a bad idea. Instead, the article claimed it is much more secure to insert it somewhere in the middle of the ...
9
votes
3answers
772 views
What is a good enough salt for a SaltedHash?
Since I'm hashing all passwords with each their own salt, is there a benefit to the salt being really random, or would an incremental counter or a guid be good enough? Also, is there a benefit of ...
