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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Using last characters of hash as salt [duplicate]

In a recent discussion somebody mentioned the following hashing scheme: passHash = sha256(password) saltedHash = sha256(passHash+passHash.substr(-10) finalHash = sha256(secret+saltedHash) The ...
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1answer
98 views

Save password on user-side for autologin

If a user wants to login to a system/server, it's recommended to have the hashed&salted password saved in a database, along with its salt. So the user wants to login, types in the password, ...
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1answer
46 views

Publicly Available API + Sensitive ID/Key Transmission Over HTTP

I've run into a predicament... I'm developing a mobile application that utilizes a server for various things. One portion is that it stores an id/key pair related to accessing and processing ...
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2answers
82 views

Is it unsafe to hash one password with more than one salt?

I'm asking my question here since I was not able to find an answer anywhere. I have written a piece of software which stores pretty delicate passwords. I have used BCrypt as hashing algorithm with an ...
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1answer
104 views

MySQL Authentication Hash Cracking

I'm currently conducting research regarding MySQL server remote authentication. I've captured unencrypted, not compressed authentication packets between the client and the server, where username is in ...
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2answers
76 views

How does salting increase security? [duplicate]

I'm currently going through a course on software security. I've recently been introduced to the idea of password salting, where a random value is concatenated to a password prior to being hashed and ...
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3answers
56 views

How to secure Password and Salt on a deployed application

I have a question regarding one step of protection more than salt/hash. I work on an application that is distributed to many clients and then deployed on their networks. If I set a password on one ...
2
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2answers
107 views

Breach informing

I am a staff member of a large fanfic site, but not the head administrator with control over the site itself. Recently, we had a security breach and the databases were copied, which included the ...
9
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3answers
4k views

How often do two users use the same password

If no two users use the same password, then in theory salting the password hash is not needed. How often, in practice, do two users have the same password?
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8answers
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Convincing my manager to use salts

My manager says we don't need to salt our passwords because people are not likely to use the same password because they all have different native languages, in addition to the websites they are active ...
0
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2answers
132 views

When I reset my password for my Microsoft account, how do they know what password I've used before?

Assumption used: all password that I've used have been salted with some random elements before hashed and stored somewhere in their database. If my previous password exists only as salted-hashes in ...
1
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1answer
166 views

Any reason I shouldn't be salting and hashing before putting through bCrypt?

I've been reading up on password storage and such, and have come to the conclusion that I need to be using bCrypt. I've got an implementation working correctly, but I'm wondering the best way to move ...
3
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2answers
118 views

MySQL ENCRYPT salt is not random?

I know there's little reason to still use ENCRYPT() nowadays, what with bcrypt being almost ubiquitous and MySQL providing better hashes such as SHA1. But while dabbling with ENCRYPT() on MySQL ...
3
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2answers
144 views

Search on encrypted data of multiple users

I want to implement a search over encrypted data. I found a blogpost, which explains 3 methods. One method is to use deterministic encryption, which I'm trying to implement. But my use case is a ...
53
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3answers
18k views

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 ...
2
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1answer
88 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
300 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
85 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
136 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
140 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 ...
1
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3answers
635 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 ...
2
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2answers
707 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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2answers
80 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
108 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
396 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
88 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. ...
124
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8answers
10k views

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
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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
197 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 ...
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3answers
2k views

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 ...
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1answer
104 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
704 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 ...
3
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3answers
429 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
153 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
171 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
89 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
256 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 ...
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6answers
809 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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2answers
212 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
608 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
245 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
208 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 ...
11
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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 ...
0
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1answer
583 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
189 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 ...
7
votes
2answers
375 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
232 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
2k 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
687 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
votes
4answers
384 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 ...