Questions tagged [key-generation]
Key generation is the process of generating keys for cryptographic purposes.
142
questions
0
votes
1
answer
14
views
Key distribution protocol involves only 2 parties, given E[k1,E(k2,m)]=E[k2, E(k1, m)]
Given an one-key cipher such that:
E[k1,E(k2,m)]=E[k2, E(k1, m)]
Is there any key distribution protocol that involves only two parties (Alice and Bob) without the key distribution center?
The protocol ...
- 1
1
vote
0
answers
19
views
Should proving key be kept as a secret in NIZK?
Hi I am quite new to NIZK. I know a trusted party (Generator) generates proving key and verifying key and then distributes them to Prover and Verifier. Apparently, the verifying key can be seen as ...
- 31
0
votes
1
answer
98
views
How proxy re-encryption works - layman perspective
Here is the use case: A uses B's public key to encrypt a message and sent it to B. In later stages, a new member C joins and B would like to let C be able to see this encrypted message (i.e., give the ...
- 47
1
vote
0
answers
53
views
What are the uses of shared cipher texts and signatures?
In Distributed Key Generation(DKG), why is there a need to actually create a master secret which can then derive into a single public and private keypair(for signatures) and a secret key(encryption)?
...
- 91
0
votes
0
answers
27
views
Enumerating values from a linear congruential generator java Random()
During my research on a java application, I discovered that the nextInt(64) function of the java.Random() class is used to ...
1
vote
1
answer
58
views
Salt value in scrypt algorithm
I see there are a lot of questions relating to handling of a salt value but nothing I have seen so far has cleared the following question.
When using a KDF such a scrypt, I believe the value of the ...
- 55
2
votes
1
answer
82
views
If the symmetric key is stolen; can I key revoke without reencrypted data?
I have a question about database security. This is a scenario I have.
The data is encrypted using symmetric (i.e., AES) and stored in a database, while the secret key is stored on the client side, so ...
- 21
0
votes
0
answers
34
views
Distributed key generation when all parties need to participate
Suppose $n$ parties where $t$ are honest want to perform a distributed key generation protocol. There are many existing schemes. In the simpler setting where all $n$ parties must be online, otherwise ...
- 325
2
votes
2
answers
391
views
Why do most authenticated encryption primitives expect an unpredictable and uniformly random key in order to be secure?
I've noticed that keys for authenticated encryption primitives like AES must be unpredictable and uniformly random in order to be secure. IV values and seeds for PRNGs also have to be unpredictable ...
- 23
0
votes
1
answer
27
views
Usage of cookies in IKE
While creating secret keys in IKE protocol, sides use cookies but I did not understand where they come from, how they are generated and why they are used. Can someone explain? Thanks.
- 27
1
vote
0
answers
14
views
Requirements of dedicated broadcast channel in Joint-Feldman protocol
I am currently reading through Secure Distributed Key Generation For Discrete-Log Based Cryptosystems, which describes a secure variant of the Joint-Feldman protocol. In this paper, in section 2 (...
- 111
1
vote
1
answer
33
views
Generating a public-private key pair from another key pair
Is the following problem a known cryptographic problem?
Find algorithms for functions $f$ and $g$, such that
$$
f(x, \alpha_{enc}) \rightarrow \beta_{enc}\\
g(x, \alpha_{dec}) \rightarrow \beta_{dec}
$...
- 113
0
votes
3
answers
126
views
AES Key vs RSA Key
I am compeletely new to cryptography and recently tried to understand it a bit more thoroughly.
My question is:
How does the Generation of keys differ in the case of AES and RSA.
I understood, that ...
- 1
1
vote
1
answer
56
views
Best practice to create an old-style installation key
All current best practices about creating and using cryptographic keys I've found, refer to creating an encrypted data out of raw data. However, there is (or at least was a few decades ago) a practice ...
- 503
0
votes
2
answers
96
views
How can I dentify the ECDHE group value used in a TLS session
In ECDHE, the group is a public value.
I want to get this value for a session. I inspected the session using Wireshark.
Under the ServerHello -> Key share extension -> Key share entry, I found ...
- 111
1
vote
0
answers
28
views
Choice of random in RSA-KEM [duplicate]
This may be nit-picking, I’m not sure so feel free to say so.
In RSA-KEM as described e.g. in Wikipedia or this answer, we choose a secret $x : 0 \leq x < n$, and send $x^e \bmod n$ for public ...
- 147
1
vote
1
answer
62
views
Generate asymmetric key pairs based on keywords such that any public key based on set containing the generating subset is valid
Let's assume we have a ton of users, and each user has a list of fruits they like - Those will be keywords. I want my users to be able to encode any data they store (Let's say, the location of their ...
- 111
2
votes
2
answers
94
views
Why is there a slight mismatch most of the time in X25519 private keys depending on functions used, but public keys always match (same seed for both)?
I'm trying to wrap my head around going from a seed to a SigningKey, and also obtaining a ...
- 97
0
votes
0
answers
39
views
Questions about Blake2x: Its state size (internal state) and its security when generating keys with size more than 256/512bits
I read the Blake2x paper: https://www.blake2.net/blake2x.pdf
It says Blake2x can be used to build a "DRBG" (CSPRNG): https://csrc.nist.gov/glossary/term/deterministic_random_bit_generator
&...
- 511
1
vote
1
answer
57
views
AWS IoT - Unique Keys per each device - Data encryption
(Probably not the right board to ask. But here goes)
I'm designing an IoT Solution with RPi as client and AWS as the server. On the client hardware, I have an Security Chip that can securely generate ...
- 11
1
vote
0
answers
69
views
Hashing function: Generate unique 3 letters Identifier [closed]
I need to create an id generation function that takes 4-digit number and returns a unique 3-letter identifier.
I already have a function that generates a 2-letter id from 3-digit number with some ...
- 111
0
votes
1
answer
42
views
Issues generating keys/cyclic group for Cramer-Shoup Cryptosystem with OpenSSL
I'm trying to implement a Cramer Shoup cryptography system in C but I've run into problems with generating the keys.
From what I have found on the wiki and in other papers, to generate keys for Cramer ...
- 21
2
votes
2
answers
296
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. ...
- 45
0
votes
0
answers
52
views
How to decompose a public key into subgroups EC?
Is it possible to decompose the public key into its own subgroups?
Suppose we know the order P with which the public key was generated ...
1
vote
1
answer
244
views
RSA key generation: why use lcm(p-1, q-1) instead of the totient ϕ(n)?
As far as I can see, generating a private key from two prime numbers p and q, having calculated ...
1
vote
1
answer
103
views
HMAC key generation and encoding
I've this piece of .NET code that is based on a Microsoft sample on how to generate a key and sign using HMACSH256.
But I've altered the key generation a little bit and also decided to use Base64 to ...
0
votes
0
answers
29
views
Is it safe to use the same seed phrase for different cryptocurrency protocols
I want to use the same seed phrase for severl cryptocoins (Bticoin, Ethereum, Nano, etc.). I understand that each protocol has its own phrase length and possibly a different way of generating the ...
- 101
0
votes
0
answers
24
views
How can I change the McEliece main parameters?
I use the Bouncy Castle Crypto API to implement McEliece in Java. I have also managed to encrypt and decrypt a message and it works without any problems.
When I use the debugger, I see that the ...
7
votes
4
answers
3k
views
Can we pick which key is private or public in asymmetric encryption? Do the keys actually encrypt and decrypt a cipher text?
Could you help me better understand how the key-pair works in Asymmetric encryption?
I'm studying cryptography at the surface level first. While reading multiple texts and talking with colleagues I'm ...
- 189
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, ...
1
vote
0
answers
77
views
Encryption of data with multiple possible decryption keys
I'm new to the Cryptography Stack Exchange, so my question might be very naive.
What encryption algorithms are out there that will allow different decryption keys to decrypt the same piece of ...
- 111
0
votes
0
answers
85
views
Design an algorithm to generate random session key
good day.
I am asked to design the a simple algorithm to generate random session key id of block length of 8 and change continuously every time it refreshes. Is there any simple algorithm to create ...
- 53
2
votes
1
answer
611
views
How is it possible to derive the public exponent from an RSA private key?
I am gonna write down formulas that I know and use to generate RSA keys.
we choose $p$, $q$
$N = p\cdot q$
$\varphi(n) = (p-1)\cdot(q-1)$
choose $e$ such as
$1 < e < \varphi(N)$
$e$ is coprime ...
- 123
0
votes
1
answer
50
views
When using prime factorization for key gen, is there a limit on the size of the prime factors?
If there is a limit, does that leave a limited number of prime numbers that can be used for key gen? And, if that is the case is the encryption system vulnerable?
- 125
1
vote
2
answers
73
views
What is this meaning disconnected from processes performing key generation or zeroization in cryptography modu
In FIPS 140-2 Part 2:Interfaces and Port in the security policy of product told :
1- "the output data path is provided by the data interfaces and is logically disconnected
from processes ...
- 29
1
vote
1
answer
82
views
How feasible is it to guess the private key of libsodium by taking into account generation time?
So suppose you are doing this locally (so no network noise), and know the exact specifics of your processor too. Is it feasible to figure out the private key (while having access to the public-key) ...
- 637
1
vote
1
answer
90
views
Gennaro & Goldfeder Key Generation Protocol
As I am going through the “Fast Multiparty Threshold ECDSA with Fast Trustless Setup” paper by Gennaro & Goldfeder, 2018, I am stumbled by the key generation protocol (Sect. 4.1, p.10):
In Phase ...
- 197
0
votes
1
answer
54
views
RSA encryption key conditions
I recently read the RSA cryptosystem but now I confused in key generation phase.
According to the Euler's Theorem, we have just one condition:
e.d = k.ϕ(N) + 1
where:
"e" is encryption ...
- 125
2
votes
0
answers
505
views
What does it mean for “1^n”(i.e., the security parameter written in unary)? [duplicate]
As it is mentioned above, I am confused about “Gen takes as input $1^n$ and outputs a key“. Does it mean that the input of Gen is 1111....111 with length of n?
- 51
2
votes
0
answers
168
views
Kleptographic attack of ECDSA key generation?
Kleptographic attacks can be designed for RSA key generation, Diffie–Hellman key exchange, DSA/ECDSA signing, etc. Is it also possible for ECDSA key generation?
More detailed: Is it possible for an ...
- 121
1
vote
0
answers
49
views
Secret key generation in the BGV scheme in HElib
This question is about secret key generation, based on section 4.7 in the design document:
https://homenc.github.io/HElib/documentation/Design_Document/HElib-design.pdf
It seems that if $m$ is not a ...
- 21
2
votes
2
answers
206
views
How many low-order bits of an RSA modulus can we safely fix to 1?
It's easy to generate an RSA modulus $n=p\,q$ of $k$ bits with $n\equiv-1\pmod{2^\ell}$, for $\ell$ up to about $k/2$: we can choose $p$ as usual, fix the $\ell$ low-order bits of $q$ to $-p^{-1}\...
- 122k
0
votes
0
answers
30
views
Symmetric and Asymmetric indistinguishabilty experiment
In each of those experiments, we have a function $Gen(x)$ who generates the key or a pair of keys respectively for symmetric or asymmetric algorithms. $x = 1^n$ : I read on other questions that is a $...
- 1
6
votes
1
answer
145
views
Schnorr groups allowing fast modular reduction, vs GNFS
I'm looking for Schnorr groups allowing fast modular reduction. Say, using the notation in DSA, with 256-bit prime $q$ and 3072-bit prime $p$, and $p\equiv1\pmod q$.
Are there standards, RFC, or other ...
- 122k
1
vote
1
answer
197
views
NTRU Euclidean algorithm the inverse of f modulo p
I am very new to the world of cryptography and have just began my research in the post quantum cryptography sector. I have been reading and trying to understand NTRU key generation and am struggling ...
- 31
0
votes
2
answers
373
views
Diffie-Hellman key generation
We all see X509 certificates with 2048/4096-bit RSA key pairs; however, it is difficult to understand how they work in the DH part of the TLS handshake.
At most, they authenticate and sign. DH 4096-...
- 35
0
votes
0
answers
56
views
SHA3_512 as dynamic SBOX generator
I'm creating a substitution-permutation cipher (for learning purposes only of course) and I'd like to implement dynamic SBOXs. The cipher will have a block size of 128, and 32 rounds. These SBOXs will ...
- 421
0
votes
0
answers
87
views
How to generate private SSH RSA key from given primes?
I have two primes and public exponent. How I can generate private key with this values and "ssh-rsa" format?
- 1
1
vote
2
answers
678
views
Recovery Passphrase Collission for BIP-39 and BIP-44
Referring to the standards of [BIP-39] and [BIP-44]: a 'master password' consisting of 12 words uniformly selected from a 2048-word dictionary corresponds to 128 bits of entropy, that is then used as ...
- 327
0
votes
1
answer
130
views
How to correctly (good practice) generate gpg keys in batch mode (unattended) WITH a passphrase
I'm writing a web interface in PHP to generate keys. I'm familiar with gpg's command line options, particularly --batch. I'm also familiar with PHP's GnuPG API.
I can't find a way to safely pass the ...
