Questions tagged [argon2]

Argon2 is a password hash or password-based key derivation function, which won the password-hashing competition in 2015.

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Designing a scheme to store encrypted data on a backend

My goal is to design an encryption scheme for the application so that the backend stores encrypted data and the whole process of encoding and decoding happens on the frontend. And you can be sure that ...
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2 votes
1 answer
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Benefit of salt in KDF like Argon2

I don't understand why I need a salt for Argon2 if Argon2 is only needed as a KDF for a password which is then called AES. At the end neither the password nor a password hash is stored. Only the data ...
3 votes
1 answer
117 views

Using Argon2, can I improve the salt join the password Argon(password,password+salt)?

I'm creating an application where I'm going to use Argon2, I'm going to have a password, and I'm going to use as salt: email+name+date of birth, you must think that my salt is silly because name and ...
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1 vote
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Django password hashes in database

can someone explain to me why django saves the hash in the database asargon2$argon2id$v=19$m=102400,t=2,p=8$... and not ...
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Argon2 derive two keys from one password

This is not a duplicate, I'm asking which method is better. I generate an encoded argon2 hash string, so it'll be stored in database to verify login passwords. Saved encoded hash has salt of length ...
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1 vote
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Wrap AES 256bit key with Argon2 without losing entropy

Given a random 256bit key used for data encryption with Streaming AES GCM I would like to wrap it for backup with AES GCM. Is it safe to use ...
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2 votes
1 answer
88 views

(How) can Argon2 be used to create both a hash for authentication and a secret key?

The Argon2 specs claim that Argon2 can be used both for password hashing and key derivation. I want to generate from a single password both a hash for authentication and a secret key to use for ...
0 votes
1 answer
145 views

Verifying Password Using Argon2

I am trying to develop a Rest API using Kotlin/Spring Boot. The JSON request in it, should have a hashed password that was done using Argon2id. Getting the password hashed was pretty straight forward ...
1 vote
0 answers
138 views

What should argon2id parameters be

I plan to use it locally on mobile devices. These seems to do not offer computational power as good as on a server. So what could be a secure argon2id parameters that run around 1s since offline apps ...
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1 vote
1 answer
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Will increasing timecost , memorycost , parallelism in argon2ID increase security in general?

currently I am using parameters for argon2ID in terms of timecost , memorycost , parallelism higher than what is recommended in RFC9106 https://www.rfc-editor.org/rfc/rfc9106.html for increased ...
1 vote
2 answers
145 views

Argon2id creating key for cryptography, how acceptable is it to use the same salt for the same encryption operation?

Everyone knows Argon2id is a slow hashing algorithm, and that's on purpose, all is good. When creating an Argon2id object a lot of parameters are needed to be taken into consideration ultimately ...
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2 votes
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Could a Yubikey Provide the Optional Secret to OPAQUE When Using Argon2?

I've been studying the OPAQUE protocol, and I like it (so far). The RFC suggests using Argon2 as the Key-Stretching Function. Argon2 can take an optional "Secret value" (2, page 5). I had ...
1 vote
0 answers
54 views

Performing client independent update of hash with Argon2

I'm trying to perform a hash update with updated parameters using argon2. According to Argon spec v3 (2.2.3 Client-indepentend Update, p. 9) the client independent ...
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2 votes
1 answer
144 views

How to derive two keys from one password with Argon2id

I'd like to derive two independent 256 bit keys for symmetric encryption from a user password. I'm using Argon2id as the password-based key derivation function. I'm planning to do the following: ...
2 votes
0 answers
51 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 ...
2 votes
1 answer
468 views

Argon2 allows a huge key length in input, but does it really provide the security of the key provided?

I read the Argon2 specification. It says in 3.1 (Page #5): Secret value K (serves as key if necessary, but we do not assume any key use by default) may have any length from $0$ to $2^{32}\text{-}1$ ...
0 votes
1 answer
135 views

XChaCha20 With a Zeroed Nonce?

We know that for ChaCha20 and XChaCha20, the same key can never be used with the same nonce. But let's say I use a random 256-bit key every time... Then the nonce can be whatever because the key is ...
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3 votes
1 answer
116 views

Questions: Argon2, its internal state and security of it when generating keys larger than 256/512 bits

Let's suppose I want to use a cipher with a large key size, such as ISAAC that supports 8192 bits ogf key. I can hash with sha-256 or sha-512 and iterate until reaches the key size but I won't get ...
2 votes
2 answers
977 views

How is Argon2 used for key derivation? [duplicate]

By my understanding, a key derivation is when you take some data, say a password, and use a function to convert it into a number that can be used as a secret key in say elliptic curve cryptography. ...
1 vote
0 answers
114 views

How is the Argon2d side channel attack performed?

How should the adversary behave in order to perform a successful side channel attack against Argon2d? I'm trying to understand the scenario that Argon2i tries to resist against.
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1 answer
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How is Argon2's Blake2b different than normal Blake2b?

This post says that Argon2's Blake2b is a reduced one, which is also agreed by Argon2's specs as it states that it uses only a 2 round Blake2b. But, on the other hand, page ...
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1 answer
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How many times is Blake2b called with Argon2?

How many times is Blake2b called with Argon2? Say argon2 thisissomesalt -d -k 1048576 -p 4 -t 20.
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What makes Argon2 also slow?

So as I understand Argon2 is a memory-hard function, in other words it has to use a certain amount of memory, thus making it effective against GPUs. So would this in theory, make Argon2 useless ...
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1 vote
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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 ...
4 votes
1 answer
482 views

Why does the GPU get a comparatively bigger advantage to the CPU when using higher parallelism in Argon2id?

My understanding is that the memory bandwidth of CPUs and GPUs is roughly one order of magnitude difference4, unlike cores which a GPU has many of and a CPU a handful. That is why PBKDF2-HMAC-SHA1 ...
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1 vote
1 answer
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Am I using these key derivation functions correctly?

I am a bit confused about key derivation functions. I am trying to use the argon2 KDF from the passlib python module to do the ...
2 votes
0 answers
38 views

Does Argon2id provide less protection against side-channel attacks than Argon2i theoretically and/or practically? [duplicate]

LUKS 2 encryption uses Argon2i as the default PBKDF. As the key is used on each access, I guess side-channel attacks are a significant threat factor. However, as I'm not a cryptographer, I am not ...
0 votes
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216 views

Encrypting cryptocurrency seeds for cold storage

I’d like some feedback on an encrypting algorithm. I’m not rolling my own, but even putting together well-proved pieces may create many pitfalls. (I don’t know if I'm stretching questioning in this ...
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2 votes
2 answers
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Is salt required in Argon2

I have software that generates user login keys randomly, we store the argon2 hash on our server. The generated keys are very strong, 64 pRNG hex characters. Right now we just use an empty string as ...
1 vote
0 answers
81 views

Encryption: filename + timestamp as info for HKDF-Expand

Let's assume that a user wants to symmetrically encrypt the files in one of his folders (being able to decrypt them later). For this, I have come up with the following procedure: A random 32 byte ...
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6 votes
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Is Argon2 "sequential memory hard"?

The Scrypt paper here defines memory-hard and sequential memory hard functions as follows: Definition 1. A memory-hard algorithm on a Random Access Machine is an algorithm which uses $S(n)$ space and ...
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1 vote
1 answer
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What does "sequential memory-hard" mean?

I found this term in Scrypt's paper. I have several questions about its meaning, ranging from how to parse it, to theoretical bounds: Q1: How to parse it? Is it read ...
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Should I use 2x the number of CPU / core for Argon2id parallelism?

I've read that I should use 2x the number of CPU available from some documentation while others suggest using between 1 and the number of CPU. I realize there is no hard answer here but I'm curious ...
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2 votes
1 answer
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How to estimate the maximum computational cost bound for Key Derivation Functions (KDFs) before it becomes useless security-wise?

From my understanding of Key Derivation Functions (KDFs), e.g. scrypt, Argon2, etc, we can tune their parameters such that it eventually becomes harder for an attacker to brute force a password-to-key ...
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1 vote
1 answer
2k views

How to choose parameters for Argon2 for a password vault

I'm creating a password vault, and I plan to use Argon2id to derive the master key from the master password. For encryption, I plan to use XChaCha20 with Poly1305. To be clear: a set of multiple ...
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1 answer
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What are some of the alternatives to password based file encryption?

With the ever increasing risk of attackers compromising password based encryption by brute forcing or guessing passwords, are there alternatives to this traditional scheme of deriving encryption keys ...
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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 ...
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1 answer
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Can you correct my understanding of Argon2? [closed]

I'm a bit new to the cryptography field (completely new), and could really use your guidance. Please, correct my understanding, as defined by the following statements. The ...
6 votes
1 answer
933 views

Is Argon2id safe from the discovered Argon2i issues?

So far, as I understand it, two ways to reduce the complexity of Argon2i have been found, one of which was fixed in Argon2 1.3, and one of which is still unfixed but is not a practical problem given ...
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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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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 ...
1 vote
2 answers
460 views

Safest alternative for hashing credit card numbers to use the hash as fingerprint?

Same question asked here in 2014 but since a lot has changed since then, I would like to get feedback from experts on the latest best practices. The problem Our requirement is to provide the ...
9 votes
3 answers
3k views

Using cryptographically random password as both the password and the salt

This question is theoretical, but will help with my understanding. All of my passwords are securely generated using 64 random letters (both uppercase and lowercase) and numbers. Using the argon2i ...
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Is it safe to use a deterministic salt as an input to KDF (Argon2)?

I'm prototyping an app that uses client-side password hashing in order to hide the "real" account password from a server (the server hashes any recieved password anyway, so no plaintext records in the ...
1 vote
1 answer
2k views

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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How secure is Argon2ID with minimal parameters?

I am trying to make the login page faster by using low ram $hash = sodium_crypto_pwhash_str($password.$MAC, 1, 10240); My question is that I dont like login page ...
2 votes
1 answer
138 views

Is iterative sha256 adequate for local password manager?

I'm fairly entry-level crypto; not a cryptographer by any stretch... I am at the level of ability to implement most of the traditional packages in python; the hashlib hashes and EAS, ECDSA ...
0 votes
2 answers
158 views

Would XOR'ing two Argon2 keys add extra security?

When a user registers on the app, they need to provide a password they create and we provide them with a randomly generated passphrase (e.g. Apple Cat Ladder Fire). We then use Libsodium's ...
0 votes
1 answer
869 views

migrate bcrypt -> argon2

We want to migrate our userbase from bcrypt to argon2. I was planning on an approach that migrates all hashes immediately to argon2; "old" users would have an argon2'd hash of their bcrypt hash of ...
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Hashing high entropy key into AES format

If I have a high entropy key (ECDHE shared secret), what type of hash should I use to format this into an AES-256 key? Is Sha256 or Sha3_256 sufficient to maintain entropy or do I need to use a KDF (...
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