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.

Filter by
Sorted by
Tagged with
2 votes
1 answer
72 views

Is there a test that put into numbers how secure a password hashing is?

As the question puts it: is there a test that can be done or a software that can be used, that is able to provide numbers/data to prove how secure a password hashing is? Say for example that I want to ...
user avatar
0 votes
0 answers
28 views

User to be able to log in without stating the user's password scheme possible?

In my database, I have a PBKDF2 hash + salt for every user. My objective is for the user to be able to log in without stating the user's password (in case somebody is logging the network traffic ...
user avatar
4 votes
1 answer
306 views

"Oblivious" Argon2id? (or comparable KDF/KSF)?

Is it possible for a client to send a blinded password to a server, so that the server does key derivation+stretching on that blinded value, but the key can then be unblinded by the client? ...
user avatar
  • 287
0 votes
0 answers
38 views

Asymmetrical scheme: insecurity concerns of saving a hash of a hash of a password

please verify or explain how to do this properly. I'm letting a user create keys from the client through a secure server. I ask the user for a password on the client, then send the hashed password to ...
user avatar
  • 109
1 vote
1 answer
52 views

How to create a key for AES in a 192 bit key length from a password?

Let's say that I have a password. And it's secure. But it's a 10-character string. So If I wanted to create an AES key for the 128-bit version of the algorithm I would just hash it using MD5. Or If I ...
user avatar
0 votes
0 answers
90 views

Hashing and Password Cracking

I was playing a game on cryptography where I encountered this problem: Hashed Value of password: 24 109 76 35 22 94 83 25 106 104 73 87 56 38 56 50 10 92 58 84 44 88 24 112 125 121 125 43 122 55 106 ...
user avatar
  • 111
2 votes
2 answers
63 views

Hashing Passwords and Hash Functions

I'm a complete noob. I was reading up on hash functions. So if a bank has its user password's run through a hash function, it'll produce a unique hash for every password right? Thus, even if hackers ...
user avatar
0 votes
0 answers
38 views

Public key cryptography for logins

This is a question sparked purely by curiosity, wanting to understand a little more about cryptography and authentication. Thanks in advance to anybody taking their time to answer. Instead of salting ...
user avatar
1 vote
1 answer
493 views

Is this authentication protocol secure against both eavesdropping and server database disclosure?

Consider the following protocol from the book "Network Security: Private Communication in a Public World" by Kaufman et al. Alice knows a password. Bob, a server that will authenticate ...
user avatar
1 vote
0 answers
33 views

How does the indexing in Argon2 work?

I am reading the original paper of Argon2 authors and I can understand the algorithm except the indexing part. Can anyone explain two things: the indexing process and the mapping $J_{1}$, $J_{2}$ to ...
user avatar
0 votes
1 answer
64 views

How safe is my pseudonymization procedure?

I work for an institution where patient data is collected and I am supposed to encrypt it. At the moment I do the following steps (with R): Randomly assigning an ...
user avatar
1 vote
1 answer
76 views

deterministic password generator idea

Outside of professional carrier, I often stumble upon a need for a unique password for exp. for local database, game server, or on tons of, not so important, websites. I came up with an idea to write ...
user avatar
3 votes
4 answers
4k views

Would this be considered a secure password hash?

I think I've understood properly, but I want to make sure as this will involve money. Password requirement is a minimum of 16 characters and must contain one of each [Upper, Lower, Digit, Other] My ...
user avatar
2 votes
0 answers
36 views

composing password hash functions

Firstly I know that what I'm asking about is not practical, so let's keep it theoretical. Let $B[H](x)$ be balloon hashing with $H$ as it's underlying hash. What happens if I do $B[H1](B[H2](x))$, ...
user avatar
1 vote
1 answer
88 views

Would it be any good to create a new cryptographic hash function?

Would it be beneficial to create a cryptographic hash function for more security. A cryptographic hash function is pretty much a pseudorandom string generating algorithm and it can easily be made ...
user avatar
0 votes
0 answers
48 views

Hashed password used for encryption and for user authentication at the same time

As I am fairly new to cryptography, I would like to understand how to, in a simple way, implement a system that would achieve the following: the user would have to setup a password, which would then ...
user avatar
  • 1
-2 votes
1 answer
43 views

Problem understanding the difference between passphrase and keyfiles

Ok, so I have read a few different articles on subject and am maybe just just having problems understanding the point of view from the program I am using or maybe not IDK. Anyhow, ill get into it. ...
user avatar
3 votes
2 answers
127 views

Don't human generated passwords used with key derivation functions reduce the security of symmetric encryption?

The key size for AES is chosen as 256 because that's considered the minimum keysize which can protect against a brute force attack - i.e. $2^{256}$ tries. However, in practice, for a lot of ...
user avatar
  • 1,637
0 votes
0 answers
64 views

Are there any best practices/recommendations for/against using client-side password hashing?

I do not mean generating a hash on the client side and then storing it in the database directly. I found a few questions with similar theme, but most of those answers assumed a scenario where ...
user avatar
0 votes
1 answer
82 views

Is server-side password strength validation possible with client-side password hashing?

Let's say I wish to setup a classic username & password authentication strategy on a server. All communication is encrypted via TLS. But ideally, I still do not want the server to be able to read ...
user avatar
0 votes
1 answer
48 views

Necessity of PBKDF2 in current Setup?

I have a single password which is random bytes that encrypts a database. Right now I am using an encryption scheme of https://gist.github.com/jbtule/4336842. To summarize, we take our one password, ...
user avatar
0 votes
1 answer
92 views

Use peppers with Bcrypt (HMAC + Bcrypt)

Is it useful to combine HMAC with Bcrypt ? If it so, should I do the HMAC on the password before "Bcrypt"ing it ? or should I do the HMAC on the Bcrypt output ?
user avatar
1 vote
2 answers
191 views

How does password_verify() function gets the salt from the password stored in DB?

I am creating a simple Sign up and Sign in form using PHP. At the sign up, I create hash using password_hash() function and then store it in the DB. At the time of Sign in, initially what I did was ...
user avatar
0 votes
0 answers
27 views

Is it possible to convert hashed password from one bcypt version to another?

I have passwords hashed using bcypt version \$2a\$ (e.g. "\$2a\$06\$...") and I want to convert them to version \$2b\$ (e.g. "\$2b\$06$..."). Is it possible to do that? If yes, are ...
user avatar
1 vote
0 answers
88 views

Estimated hardware cost to crack ARGON2ID hashed passwords

I can find a bunch of information on stuff like bcrypt and script, but I am interested in estimating the cost per hash on something like Argon2id that is GPU hardened. I am trying to do the best with ...
user avatar
7 votes
3 answers
3k views

Password hash contained '\x00' in middle, resulting in ValueError from bcrypt.hashpw

I have some code that accepts a password in string format, and hash it with SHA3-512 before passing it to bcrypt for hashing. However, by some coincidence, I found a test case that produces a hash ...
user avatar
  • 173
5 votes
2 answers
804 views

7-Zip Encryption: Practical Effect of Lacking Salt

A previous discussion on Cryptography StackExchange leads me to understand that 7-Zip does not use salt to derive an encryption key from password to use its AES-256 encryption; that this is a ...
user avatar
1 vote
2 answers
184 views

Would hashing a password twice prevent naive attacks?

A common way of using MD5 or any other hashing algorithms to store passwords is to hash the password with a salt $$\text{hash}(\text{password} \mathbin\| \text{salt}).$$ This way, if an attacker wants ...
user avatar
0 votes
1 answer
127 views

How to generate different hash values for same files/messages?

I was generating HashValue for contents in the file. I want a different hash value every time I wanna generate even if the file is the same. I am using SHA256. For the same files, the hash value I am ...
user avatar
1 vote
1 answer
214 views

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 ...
user avatar
  • 421
4 votes
2 answers
446 views

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. ...
user avatar
  • 142
0 votes
1 answer
85 views

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 ...
user avatar
  • 21
0 votes
2 answers
450 views

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 ...
user avatar
  • 17
1 vote
1 answer
123 views

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 ...
user avatar
1 vote
2 answers
397 views

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 ...
user avatar
0 votes
2 answers
78 views

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 ...
user avatar
1 vote
1 answer
179 views

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 ...
user avatar
  • 91
0 votes
0 answers
49 views

What is the purpose of hashing the identifier in the secure remote password (SRP) protocol? [duplicate]

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 ...
user avatar
  • 1
2 votes
1 answer
73 views

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?
user avatar
3 votes
1 answer
46 views

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 ...
user avatar
0 votes
3 answers
624 views

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 ...
user avatar
  • 101
-1 votes
1 answer
904 views

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 ...
user avatar
  • 3
1 vote
1 answer
126 views

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 ...
user avatar
1 vote
1 answer
273 views

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 ...
user avatar
0 votes
0 answers
52 views

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 ...
user avatar
3 votes
4 answers
1k views

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 ...
user avatar
  • 159
2 votes
1 answer
326 views

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 ...
user avatar
2 votes
1 answer
143 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 ...
user avatar
  • 123
0 votes
2 answers
174 views

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....
user avatar
0 votes
1 answer
1k views

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 ...
user avatar
  • 1

1
2 3 4 5