Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [key-derivation]

In cryptography, a key derivation function (or KDF) derives one or more secret keys from a secret value such as a master key or other known information such as a password or passphrase using a pseudo-random function. Keyed cryptographic hash functions are popular examples of pseudo-random functions used for key derivation.

4
votes
1answer
357 views

Use RSA keys to derive AES key

I have 2 end points where I would like to derive the same AES key. Every end point has its own RSA key pair and RSA public key from the other end point, and I would like to combine them somehow on ...
2
votes
1answer
64 views

How to encrypt sensitive files in a business application? Is it needed?

I'm currently working on a business Java application, and we store sensitive files related to our users. What is the appropriate approach to store them securely? Is it viable to encrypt/decrypt all ...
2
votes
1answer
387 views

NIST SP800-108 KDF modes comparison

According to NIST SP800-108, there are three modes that can build KDF from PRF: counter mode, feedback mode and double-pipeline iteration mode. Assume that the same PRF and input distribution are used,...
1
vote
1answer
624 views

DUKPT MAC Variant key

I'm currently implementing an interface that makes use of the DUKPT (Derived Unique Key Per Transaction) scheme to generate MAC keys. This particular interface uses a different (variant) of the MAC ...
14
votes
0answers
478 views

Memory-hard password hash in practice?

Dan Boneh, Henry Corrigan-Gibbs, and Stuart Schechter have proposed Balloon Hashing: A Memory-Hard Function Providing Provable Protection Against Sequential Attacks (in proceedings of AsiaCrypt 2016). ...
5
votes
0answers
83 views

Is correlation in vector distributions “dangerous”?

Consider the two vector distributions $\xi,\chi$ described below, each one outputting integer vectors of length $n$ with coefficients in $\{0,\dots,n\}$. Distribution $\xi$ samples each coefficient $...
4
votes
0answers
98 views

Why does the Signal protocol use AES/CBC instead of AES/GCM?

AES/GCM has obviously proved itself to be better than AES/CBC. Unless the key is re-used with the same initialization vector (see disadvantages of GCM). More information of its advantages against CBC ...
4
votes
0answers
58 views

Upgrading key derivation by adding a XOR with a known value

In general keys for password based key derivation are derived from a password hash such as the old PBKDF2 function or Argon2, possibly followed by another derivation function to derive data and ...
4
votes
0answers
327 views

Storing password or derived key in keychain?

Currently I am developing an application that stores and reads encrypted data. The data is encrypted with AES and the actual AES key is derived from the users password (and some nonce) with PBKDF2 ...
3
votes
0answers
57 views

Did “The Catena Password-Scrambling Framework” make an error in the reduction of its pseudorandomness?

I was reviewing the most recent version of the Catena paper and they made some claims that I find questionable in their reduction of the pseudorandomness of the output of Catena (p. 32). First I will ...
3
votes
0answers
129 views

ECIES: Purpose of optional shared information?

According to Wikipedia the ECIES algorithm has two optional shared information $S_1$ and $S_2$. They are used as follows: Generate a random shared secret $Z$ according to ECIES, which will never be ...
2
votes
0answers
67 views

Derivable encryption key - BIP0032 parallel

I wish to find an asymmetric encryption algorithm that supports key derivation, BIP0032 style. Meaning that I have some SEED [PRIV] and I give someone some public data [PUB], then given new public ...
2
votes
0answers
73 views

Is my deniable encryption scheme reasonable?

I was experimenting with RubberhoseFS, but since it is very hard to compile on anything modern, I decided to implement my own version, stripped of many unnecessary features. Namely, my implementation ...
2
votes
0answers
42 views

Why would one split HKDF output into multiple parts instead of expanding it multiple times

Reading the implementation details of Signal's approach on double ratchet algorithm I noticed the following key derivation procedure for using AES-CBC with HMAC: HKDF is used (...) to generate 80 ...
2
votes
0answers
30 views

Use derived keying material as key for stream cipher

Section 7.3 of SP 800-108: To comply with this Recommendation, the derived keying material shall not be used as a key stream for a stream cipher. Footnote: The level of security provided by ...
2
votes
0answers
41 views

Key update and re-keying

What is the exact difference between the key update and re-keying? Following the discussions here, I understood that the key update is the process of deriving the new session key from old key. In the ...
2
votes
0answers
349 views

Curve25519 / Ed25519 - Generate a private key from this term

I have 2 key pairs $(x_1, y_1)$, $(x_2, y_2)$. I also have $a = $random 256-bit array and $b = $256-bit of defined values from me. I know the values for $(x_1, y_1)$, $x_2$ and $b$. But I miss the ...
2
votes
0answers
61 views

Sharing salt for deterministic symmetric key derivation

I have a requirement to generate and share unique symmetric keys for a large numbers of small data objects. In many cases the storage and retrieval of the key for each object will be a significant ...
2
votes
0answers
80 views

Can proofs be relayed to derived keys?

I am aiming to find out if this problem/puzzle can be solved with cryptography at all. Say there are these two parties: Subject S which has a master private/public key pair (MPriv, MPub) and a set of ...
2
votes
0answers
204 views

The right way to encrypt sensitive data with an user password

I am developing something like 1Password and I want to be sure that method that I use is secure. Main idea of the app is storing user passwords, and is protected with a global master password. Main ...
2
votes
0answers
140 views

How does FileVault2 Recovery actually work?

I'm a crypto-enthusiast but no expert at all, that'll explain why i didn't understand. Also please consider english isn't my native language :) I am about to enable FileVault2 FDE on the new macbook ...
1
vote
0answers
50 views

Which 'info' and 'salt' parameters to use in HKDF for TLS 1.3?

all the following discussion is for HKDF in TLS1.3: Regarding the 'salt' parameter in - HKDF-Extract(salt, IKM) as written in RFC 5869: HKDF without having to protect the secrecy of the salt. In ...
1
vote
0answers
41 views

Reason for including the public key of the key agreement in the KDF

I found the following text when looking up KDFs: In comparison, the so-called DHAES mode in IEEE 1363a mandates to use the binary representation of the sender’s public key as an input parameter. ...
1
vote
0answers
41 views

Is there hierarchical key generation that completely tolerates leakage?

Is there a hierarchical key construction algorithm that achieves forward/backward privacy with any (unlimited) leakage of private non-master keys? What I mean is that if there's an unbounded number ...
1
vote
0answers
86 views

Securing MQTT communication

I am building kinda simple IoT project, but I would like to implement good security (just for educational purposes and fun). My plan is to build simple solution where one arduino board reads some data ...
1
vote
0answers
37 views

Question on inputs of PRFs and HKDF KDF

I've read a lot of information about PRNGs, PRFs and KDFs. As far as I know: PRNG: The seed for the PRNG must be a uniform string. It transforms a short real uniform string into some bits of pseudo-...
1
vote
0answers
36 views

Time-sensitive key derivation for sharing with third-party

Devices: In this system, users have one or more wearable devices (a smart watch), one of which they will most likely have on their person all the time. The devices are linked to their account by their ...
1
vote
0answers
119 views

HKDF to derive multiple keys from a strong constant master secret and a weaker changing secret

I am working with constrained nodes (type OpenMote CC2538) on a (constrained) 6TiSCH network and I am trying to design a good re-keying scheme designed to generate AES-128 keys dubbed Device ...
1
vote
0answers
148 views

Problems key AES 128 key from last round key

I have written an algorithm in Python to find the main AES 128 key from the last round key. However, it doesn't work; I can not find back my main key. I know that the general principle is to do $w[i] ...
1
vote
0answers
255 views

Can I use a random number generator with seed for key derivation?

I don't know a thing about cryptography so I'm judging by what I see in APIs docs. I want to use ECDSA or ECDH in my project. And what I know so far about key derivation in this systems is that they: ...
1
vote
0answers
35 views

Shall I use individual or common signing keys for different roles?

I have a server S to which a client system can establish connections using predefined roles R1, R2, ...Rn. For mutal exchange of data and for authentication with GCM/GMAC a set of symmetric AES-128 ...
1
vote
0answers
2k views

What is the use of key iterations?

I read about PBKDF2 on Wikipedia and seen few apps. having option to manually enter number of iterations. I am still not clear on this. (1) With what I understood, key iterations can be used only ...
1
vote
0answers
44 views

Using multiple iterations of Argon2i

Consider Argon2i used as a key derivation function (implemented by the libsodium crypto library) to derive an encryption key from a password. Additionally, when entering the password a second time, ...
1
vote
0answers
57 views

Password manager that uses a mix of long and short key derivation functions

I was reading "A Convenient Method for Securely Managing Passwords, Halderman et al., 2005". In short, the authors say to do the following: ...
1
vote
0answers
195 views

Need help with PKCS#12 3 key triple des key expansion

I am trying to decrypt PKCS8-Shrouded Key Bag inside a PKCS#12 pfx file. The oid for the encrypted data is PbeWithSHAAnd3-KeyTripleDES CBC. Iteration count and salt has been provided within the pfx ...
1
vote
0answers
103 views

Hardening of random number generators

Boxcryptor uses various CSPRNGs and apparently hashes the output using PBKDF2 to derive the final key. Even though the choice of ...
1
vote
0answers
1k views

How do I generate decryption keys for the IDEA algorithm from the 128 bit key?

I am trying to implement IDEA algorithm in C#, just to learn how it works. I have taken a 128 bit binary key and generated the 52 encryption keys using the following code: ...
0
votes
0answers
63 views

Using OpenSSL to emulate LTO 4 tape encryption

I have a mix of LTO 4 and LTO 3 tapes I would like to encrypt data on to. LTO 4 has built in encryption - load they key into the drive, and it handles the AES-256-GCM encyption transparently. LTO 3 ...
0
votes
0answers
139 views

key hierarchy management and master key

I have this equation, $E_{K_{as}}(E_{K_{bs}}(K_{ab}))$ which means $K_{ab}$ is encrypted by $K_{bs}$ then whole packet is encrypted by $K_{as}$. I think the key structure is $K_{as}$ is the master ...
0
votes
0answers
96 views

How to derive a key from an existing AES key?

Currently, the code I am staring at uses the CKM_EXTRACT_KEY_FROM_KEY mechanism. That has been disabled in our hardware module, so I need a different mechanism to ...