A salt is a random addition to a password to make the hashed password less susceptible to a lookup table attack

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How can I create a password that says “SALT ME!” when hashed?

How can I create a password, which when directly hashed (without any salt) with md5 will return a string containing the 8 characters "SALT ME!". The hope is that a naive developer browsing through his ...
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1answer
63 views

How difficult it is to solve a salt if knowing the original data and the hash output that uses the SHA-2 algorithm

I am reading the documentation for Kentico where it describes using hashes to validate query strings ...
2
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4answers
201 views

How does a system authenticate a user using a hash function, after it has been salted?

I don't really understand how salting works. I read the Wikipedia article, but I still don't understand how can a system authenticate a salted hash? Let's say a user chooses a password. It's randomly ...
2
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4answers
59 views

Random salt - necessary for a single user?

Based on: http://security.stackexchange.com/a/33520/42220 and http://security.stackexchange.com/a/41630/42220 I can see the benefits of a completely random salt per user. If I am implementing an ...
2
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1answer
49 views

php crypt - trailing dollar sign - extract only the salt part from hash - padding the salt

I am reading up on PHP's crypt() function. I have a few questions on it - What is the significance of the trailing '$' sign at the end of the salt string that I see in most examples. The manual ...
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1answer
82 views

Hash Security of Windows 7 Password

I need to find some materials about how Security Accounts Manager(SAM) works in windows 7+. I am confused with the storage format of hashed value. Many materials (such as, 1) tells me that it uses ...
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3answers
204 views

Is Salt, IV and Key necessary when encrypting password in a database using AES? If so, how should they be used?

Imagine I have a website with user accounts. I want to authenticate users, so I need to know if the password they provide matches the one stored in my database. To protect the passwords from prying ...
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2answers
210 views

How weak is MD5 as a password hashing function ?

A professor told us today, that MD5 is weak. I understand his chain of thought but pointed out, that IMHO MD5 is a good way to go if you would use a long (even really long) dynamic salts and static ...
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56 views

How do you overcome the problem of the salt being public and known by the attacker? [duplicate]

I believe that when adding a salt to the password you need to store the values so you can compute the hash again. But, what does happen if the attacker get the salt? How is it possible to add value ...
0
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3answers
92 views

Using a Hash as a Salt? [duplicate]

Ive done a bit of reading on the subject of Hashes and Salts and I came up with an idea for a salting scheme but I wanted to check it with some people more learned than myself. My basic idea is to ...
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3answers
255 views

What is the correct way to make a password salt?

I've made the below function to make a completely random 64 character long hash function password_salt($password){ $salt = hash("sha512", mt_rand(1,100000) . strtotime("now") . $password . ...
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2answers
56 views

How to use ESSIV to avoid seeing repeated patterns?

I'm trying to implement an encrypted file-system. The file-system consists of 512-byte sectors. I encrypt/decrypt the contents of a sector as follows: Compute the SHA256 sum of the user password. ...
95
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7answers
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Why are salted hashes more secure?

I know there are many discussions on salted hashes, and I understand that the purpose is to make it impossible to build a rainbow table of all possible hashes (generally up to 7 characters). My ...
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0answers
58 views

How do I determine whether a Linux-based router still has the default password? [duplicate]

My goal is to check if the password used by admin is the default password. I work on a Linux-based router. I know the password is stored as a hashed value in /etc/passwd. In generic Linux machines, ...
0
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1answer
121 views

Hashing Passphrase in Client-Side JavaScript Rather than Server-Side — Is it Viable?

Yet another salting-and-hashing-for-web-sites question has been left on the doormat of Information Security's StackExchange. The oft-mentioned approach for website password-handling is to use a ...
16
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3answers
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Is it safe to write the salt AND/OR the IV at the beggining of an encrypted file?

I want to encrypt a file with AES in CBC mode (maybe another mode is better for file encryption...I don't know, but suggestions are welcome!). What I usually do is that I first write a few random ...
1
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1answer
90 views

Sending Salts For Key Generation

I am working on a project that uses a combination of a web based framework (Django) and an installed app (Python) for the purpose of data entry/upload. I will have to send medical records over the web ...
3
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2answers
243 views

Why would you need a salt for AES-CBS when IV is already randomly generated and stored with the encrypted data?

I was looking at this code and came across these comments which says encrypting without a salt is insecure. Why would it be insecure when you are already using a random IV for each value? I think the ...
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3answers
322 views

Why not hashing and salting passwords?

When I was implementing my webapp, I decided to hash and salt users' passwords in order to protect them, even though I knew that there will never be a lot of them ... if any. Of course, I'm not saying ...
3
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1answer
148 views

using counter instead of salt for hashing

I'm developing own protocol for secure message exchanging. Each message contains the following fields: HMAC, time, salt, and message itself. HMAC is computed over all other fields using known secret ...
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2answers
108 views

Do I need to salt PBKDF2 when it's used for AES encryption

If I'm using PBKDF2 to stretch a password into a suitable key for use in encryption with AES, should I be using a random salt (for PBKDF2, not the AES IV)?
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1answer
87 views

Transmission of messages

I am currently developing a game which will be run in a client, they will sign up for this game online and create their account there, their information will be stored into a MySQL database. I am ...
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3answers
244 views

help me about salting passwords

Eve has just discovered and decrypted the file that associates each userid with its 32-bit random salt value, and she has also discovered and decrypted the password file, which contains the ...
6
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6answers
710 views

Is it useful to protect hashed password with encryption?

Imagine that I am hashing the users' passwords with a random, long enough, salt, using key stretching, and a secure hash. Would it be more secure to finally encrypt the hash with a symmetric key?
4
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1answer
156 views

Would re-salting passwords regularly in-/decrease security?

What are the (dis)advantages of re-salting a user's password regularly, e.g. weekly (or at their next login once week since the last re-salting)? The basic idea would be that users who regularly log ...
3
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1answer
438 views

Reverse-engineering password salts

Lets set out a scenario, a database has been dumped and all the passwords are hashed. You notice that some users seemed to have signed up twice and have the same hash. You run these hashes through ...
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1answer
190 views

Challenge, Authentication and session key

I programmed an application on Linux using C, I added an authentication and cryptography layer that's going like this : 1 -client sends connection request. -server send a random challenge to client. ...
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2answers
194 views

How can I generate a unique SALT for multiple apps sharing one user database?

Let's say that I have one Database, and several separate web applications that share the database. If hashes are to be unique and generated on the server-side, how can I ensure that I am generating a ...
10
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6answers
1k 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 ...
0
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1answer
552 views

How long would it take to brute force the AES encryption?

I'm trying to write a secure code that can keep my site users passwords as safe as possible. Now I'm fairly new to encryption and would like some professional opinions and suggestions. As well as a ...
3
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3answers
171 views

Proper storage/use of salted passwords?

If a salt is not stored along with the hashed password in the database, is it possible that the password is salted? I ask because in a system I am working on there is only a password column, but when ...
6
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2answers
329 views

Salt placement prior to one-way hash

In one-way hashing its common to prepend or append the salt to the secret and then hash it: (salt + secret) or (secret + salt). I was thinking of this metaphor as salt falling on a plate of food. It ...
0
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3answers
190 views

Need references about why public access to a password hash and salt is poor practice

What are some published industry standards about why revealing the password hash and salt are poor or bad practices from a security perspective? I am dealing with a vulnerability where anyone can ...
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3answers
957 views

Generating an unguesable token for confirmation e-mails

I'm generating a token to be used when clicking on the link in a verification e-mail. I plan on using uniqid() but the output will be predictable allowing an attacker to bypass the confirmation ...
4
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3answers
550 views

How often should I reset my salt?

I'm thinking of implementing a salt recycling scheme on my user credentials database. The motivation behind this decision is that even if the attacker manages to get his hands on the database and has ...
4
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4answers
304 views

User password as key instead of hashing it

I was reading here on Hashes and Salts and I thought about another method to do user authentication. I need your thoughts on this as I might be overlooking something. Scenario: For web application ...
2
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1answer
625 views

How to save the random salt to the database

As I understand it, salting and hashing passwords is the way to go. I also understand that to authenticate a salted and hashed password, the random salt needs to be saved. Does this mean that if I use ...
8
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3answers
792 views

Is this code snippet good enough for password hash and salt

After a few days reading up about salting and hashing passwords, I found an actual bit of code that tells how to do it. This is what I found: $blowfish_salt = ...
5
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5answers
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Is it a good idea to use an input by the user as SALT?

I have read many Q&As here on IT Security about password hashing and salting. I am building a simple registration form for our community website which will be used by our members to create their ...
3
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3answers
516 views

How can salted, hashed password storage be combined with a plaintext, nonce and hash based authentication?

My understanding is as follows: To securely store a password (e.g. in a database), you use a hashing algorithm designed for this purpose (designed to be slow, e.g. bcrypt), and you use a unique salt ...
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1answer
187 views

After salting my passwords, are they protected against dictionary attacks? [duplicate]

I use sha1() to hash my users passwords, but recently a friend told me that if someone get the hash then they could use dictionary attack and he recommended using salts. I implemented a random salt ...
-1
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3answers
181 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 ...
3
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4answers
316 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 ...
29
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7answers
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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 ...
0
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3answers
318 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 ...
20
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4answers
1k 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 ...
5
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2answers
342 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 ...
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2answers
290 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
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4answers
421 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 ...
3
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2answers
1k 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 ...