Questions tagged [password-hashing]

Irreversibly converting user-selected passwords into authentication tokens that can be safely stored e.g. in a user database. Typically done with a salted password-based key derivation function (PBKDF), ideally with a memory-hard mixing stage to thwart brute-force attacks using parallel hardware.

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Do I need a salt for Scrypt if the data is client-side?

I have a web app, in which I am encrypting user data client side. Each client has their own password, which is used to derive an encryption key (via Scrypt) for encrypting their data. Since the data ...
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Why are leaf nodes hashed in merkle tree?

I was reading the following on Wikipedia, it appears that the leaf nodes are hashed. What are the benefits of this? Why is it done?. I fell like they are done so that they can be transferred securely. ...
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How do high hash rates affect hashed password security?

Given the increase in hash rate since the rise of numerous block chains, I wonder how this affects the security of many hashed password systems. Is a standard linux ...
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Match bcrypt hash with plaintext

I have a bcrypt hash: $2b$10$kn7yEh2nYiDqDYNY.hjiZOtASBKT9uO4KozbFWDW2XLYnW58nkpq and a list with given plaintext passwords. How can I get the password from the ...
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Do you use a salt when encrypting a password or just when hashing a password?

A password is used to connect to a database. This password is kept in a file. This password (therefore) needs to be encrypted. A program to access the aforementioned database needs (of course) the ...
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How long would it take all of the supercomputers or cloud computing on Earth to bruteforce a significantly long password?

I was arguing with a colleague who thinks that SHA256 (password + 64 character static salt) is "insecure." My argument is that nothing in cryptography is "secure," it's all a ...
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Is this method of salting effective?

So this is my first post on this forum, so bear with me if I sound stupid. I am creating my own web application with JavaScript and MongoDB. I am storing all user information in a Mongo table, and ...
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Can ECDSA signature signing and verification process replaces password hashed based login system?

ECDSA or DSA in general was to sign a message or data using private key and verify it using public key, if the attacker/imposter doesn't have the private key then they couldn't sign the message ...
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What is the purpose of hashing the identifier in the secure remote password (SRP) protocol?

In the secure remote password protocol version 6a, the identifier for the user, I, is hashed along with the salt and the password on the client. While I understand ...
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How do salt and initialization vector differ?

Reading through the NodeJS API docs I came across IV for the first time. From what I can tell it has the same role as a salt in password hashing? Are they equivalent?
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Parallel random-access machine resistance in memory-hard functions

I'm trying to add memory-hardness to a hash function. A link to the specific line where that part of the implementation starts can be seen here. The basic approach is this: (1) Concatenate a string of ...
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Industry standard recommendations for memory usage defaults for a password hashing function?

I've been looking around for any studies done on this topic with respect to memory-hard password hashing. I'm inclined to simply impose no extra overhead by default, to be honest, but I'd really like ...
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Why is SHA256/SHA512 not broken for shortish passwords

I don't get why SHA-256/SHA-512 hasn't been broken, at least for shortish (10-12 character) passwords It is perfectly plausible to pre-compute a password/hash-pair table using numerous very fast ...
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Salt length in SHA-512 version of Unix crypt command

SHA-512 crypt specs reports that SHA-512 crypt uses 128bit salt. The FreeBSD/Linux password generation code builds the salt using 16 bytes random data (128bits) and then it translates the random data ...
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What weaknesses would SHA256 hash array building and hashing the result have for password storage?

You allocate a 1MB array. Salt the password (this is the only time the salt is used other than being stored at the end) and hash the password with SHA256 8 times. Place 31,250 copies (125,000 was ...
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Is this password-cracking challenge possible?

Taking a graduate computer security class, part of our current assignment is to crack 50 Unix md5crypt password hashes, due on Thursday, October 8th (in eight days.) I've managed to crack 49 out of ...
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What can be deduced/extracted from this local hash extracted from Windows Machine?

I'm new to cryptography. I've been experimenting with getting Windows hashes to see whether it's possible to reverse engineer. The following hash is what I got from my test laptop. What can you ...
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Could a fixed RSA encryption be used instead of a salt to prevent rainbow table attacks?

It's common to use a salt before hashing a password in order to prevent an attack by rainbow tables. Would it also work to encrypt the password for instance by RSA encryption - by a permanent RSA ...
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Difference between server salt and client salt?

Basically I am trying to understand the difference between server salt and client salt. I know that the client salt is used to make encryption harder for hackers, but I can't seem to grasp the concept ...
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101 views

How long would it take to calculate the hash of a password by hand?

Suppose one had no computer (or rainbow tables), but had access a pen and paper as well as all the necessary documentation for modern (best practice, not outdated) hashing algorithms and mathematical ...
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How do I calculate Base64 conversion rate?

Basically I need to have a base64 encoded signature that has to be 96 characters long. However, I do not know what length I need to have the signature at so when I encode it, it can be that exact size....
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Choose Argon2i or Argon2id for secure password hashing on a website? [duplicate]

I make a website with authentication. I have studied a lot of answers to these questions, but I still don't understand what is better and safer to use for a website: Argon2i or Argon2id? I know which ...
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How secure is a password generator that runs SHA256 on a passphrase

I was looking into how password managers work and it seems to me that they all store the passwords (albeit encrypted). How secure would a scheme be where the password manager always generates the ...
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How do NTLMv2 hashed passwords work?

We have an application which embeds NTLMv2 password hashes into its configuration. In attempting to assess the security of this practice, I'm not finding much straightforward information about how an ...
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AES with a longer key instead of key expansion? [duplicate]

What are the disadvantages of using AES-256 with 240-byte key (which scrypt/bcrypt/argon2/pbkdf2 can easily output) instead of an expanded 256-bit key? The only disadvantage I can think of is "no ...
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Does having a hash of a password jeopardize the security of plaintext that was encrypted with that password?

A malicious actor wants to decrypt ciphertext that was encrypted with a password. He also possesses the hash (bcrypt/PBKDF2) of that password. Does he have any significant practical advantage in ...
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Relation between Zoom id,password and join URL [closed]

We all are using zoom application for joining/hosting meetings in this corona virus period. As we create a meeting, a new id, password and a url is generated. Some real examples follow- Id: ...
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Hashing-Simple Hash and Merkle tree [closed]

Does the output hash of simple hash and Merkle hash are same for same data>>??
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Short term for “Purposely-slowed hash”

When Argon2, Balloon, scrypt, bcrypt¹, PBKDF2… are used for a password, we can call them password hash (for password storage) or password-based key derivation function (for use in encryption). But ...
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how many iterations of SHA3 (keccak256) hashing would be required to provide reasonable protection for the following data structure?

((A , B , C) , (D , E , F, G, H)) Where: A is 0x0-0xF, (1 of 16) B is 0x00-0xFF (1 of 256) C is an 8 digit integer D is a one of a list of one hundred words padded to 12 characters E is a one ...
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Argon2id benchmarks

Recently I've decided to publish a simple app that I am using for maintaining and storing sensible encrypted data on the cloud. https://www.microsoft.com/store/apps/9NSGBQSJ2HD6 The hashing is done ...
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Do we still need Multi Level Password Hash if Brute Force is not a matter

I am developing a web application where user can SignUp and all that kind of stuff. I was doing some research about Hashing and Storing passwords in Database and came across this article. In this ...
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Does pepper *require* an HMAC?

Assume you are already given a properly-salted, password hash $X$ from some slow PBKDF (e.g., like Argon2id). Now, you want to apply some large (~256-bit) secret "pepper" $S$ to it before storing it ...
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Length extension attack in the middle help!

is it possible to insert the command that you want to execute in the middle of the md5 hash token already known?
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How to bruteforce password from HMAC-SHA256 hash (if you have the key)?

Short of creating one's own script / program, is there an existing, readily available way of iterating through a list of potential passwords to find which one corresponds to a hash (HMAC-SHA256), ...
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How to pad a 448 bit message for SHA256?

I recently implemented a very simple SHA256 hashing program in C++, since the SHA256 hash function's block size is 512 bits or 64 bytes, and messages less than that size have to be padded as per the ...
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Signal Key Stretching Regarding Their Blog Post

I just read this blog post (Signal - Technology Preview for secure value recovery) by Signal and something is not quite clear to me. In section "Stretching beyond a KDF" they generate a ...
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How passwords are fed to key derivation functions?

Suppose I want to encrypt data, send it over the network, and decrypt it on the receiver side. I know the elegant way to do this is by using a symmetric key to encrypt the data and an asymmetric key ...
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Choosing between hash functions instead of providing a salt for a password hash

I am working on some programs that require the users to store their passwords in my databases. However, due to the fact that I am not sure whether salt should be stored in databases due to my ...
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How slow is the hash used for Mac FileVault encryption?

Certain password strength estimators (for instance, zxcvbn) give estimates that vary with the speed of the hash and the assumed resources of the attacker. I am curious what hash is used by the MacOS ...
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How to securely store and validate a 4-digit PIN used on a mobile device?

I want to be able to securely (1) create and (2) validate a PIN, typed by a user primarily in a mobile app. There is no 'typical' password, although there is another 2nd factor. The starting point ...
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Two party protocol using only hash function

I have been told by my professor to compare two passwords as we do it in Yao's two-party protocol but without using any crypto functions. We are only allowed to use a hash function. The passwords are ...
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Cracking hashes: With vs without knowing the salts

Let's assume the following situation: The attacker has extracted 1000 password hashes from a website (vuln.com) along with all their usernames and hashing ...
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Password hash salt

I'm asking this question to have a professional opinion about this, and to check if my assumptions are correct. The question derives from few comments I exchanged on SO: Problem with login I can login ...
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Losing entropy after re-hashing a hash

Suppose you have a string AAA that was hashed with SHA1 to produce 606ec6e9bd8a8ff2ad14e5fade3f264471e82251. If I rehash ...
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Risks hashing salt + 5 - 8 number pin with PBKDF2

I have been tasked with putting a simple sign in experience in place where the user types in their ID and a 5 to 8 numeric value as the password or PIN as it is called here. I am using ASP .NET Core ...
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Is there a PAKE algorithm that is fully resistant to a server data leak?

I'm looking to build an authorization system with a completely "public" server which involves two assumptions: The server's data is public The server is incorruptible and uncrackable i.e. nobody can ...
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Argon2 or scrypt instead of PBKDF2 with AES

Is using scrypt or argon2 a better key stretching technique with AES compared to PBKDF2 or bcrypt with regards to a quantum computer brute force attack. The brute force attack I'm referring to is ...
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Why are good passwords required if we use good hashing algorithms?

Again and again are we adviced to make good passwords: At least 12 chars, numbers, signs, upper and lowercase. But why is that really needed? I can see the need, if the system uses a hashing ...
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Clarification of NIST Digital Identify Guidelines and “Pepper” in Password Hashing

For password hashing the NIST Digital Identity Guidelines state In addition, verifiers SHOULD perform an additional iteration of a key derivation function using a salt value that is secret and ...

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