Questions tagged [keys]

Private and secret keys consists of secret information used as input to various kinds of cryptographic algorithms such as encryption, signature and MAC to select the concrete transformation done by the algorithm.

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Providing tokens for anonymous survey

I want to conduct an anonymous Internet survey (e.g. “What’s your favorite fruit?” with a multiple choice answer) among a given set of people. Double answers by the same participant are not allowed. ...
Alfe's user avatar
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1 vote
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Issue with AWS Encryption SDK for JavaScript in Browser: 'Buffer is not defined' [closed]

I'm trying to implement AWS Encryption SDK for JavaScript in a browser environment within a React application. When I attempt to construct an instance of the encryption client using buildClient ...
CreativeDesign's user avatar
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PGP key pair - How to set up for multiple users to decrypt messages with Kleopatra [migrated]

This is my first project of this nature, and I am hoping this is a basic use case for PGP encryption. Please forgive my ignorance! There is a server being configured by a service provider (SP). The SP ...
Clifford Piehl's user avatar
2 votes
1 answer
58 views

Security of RLWE encryptions of secret keys

Under which conditions is it secure to publish an encryption of the secret key $s$ under itself in terms of an $RLWE_s(s)$ ciphertext? Because for some schemes this is (repeatedly) used in ...
opag's user avatar
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2 votes
1 answer
55 views

Key management problem in federated learning based on homomorphic encryption

In federated learning using homomorphic encryption, all participants in most schemes share the same pair of keys, which can easily cause key leaks and lead to data privacy leaks. After research, I ...
sunmu's user avatar
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3 votes
1 answer
105 views

What is the result of not connecting the 1st register to the xor gate in LFSR?

I designed 8 bit lfsr in vhdl. According to mathematical theory, I xor processed the outputs of registers 1, 4, 5, 6 and 8 and connected them to the input of register 1. theory says that if I give the ...
Doğukan Karakaya's user avatar
2 votes
2 answers
59 views

DES initial key generation

I am working through a textbook on crypto, currently on DES section. What bothers me is that there was no explanation about where do we get initial 64-bit key from. This question is also very hard to ...
Michael Hammer's user avatar
0 votes
1 answer
110 views

If I encrypt two plaintexts with different keys, XOR the ciphertexts and send to an adversary, what can he/she do with what I sent?

Let's suppose I encrypt two blocks of 1MiB with AES-256 in CBC mode, each one using different keys, XOR the resulting ciphertexts and send this XORed block to an adversary. Remembering that the ...
alpominth's user avatar
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0 answers
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Hashing a seed full of entropy with a cryptographic hash function and emiting a key with the same size as input: can a collision attack occurs?

I read this in the documentation of HighwayHash: By contrast, 'strong' hashes such as SipHash or HighwayHash require infeasible attacker effort to find a hash collision (an expected 2^32 guesses of m ...
alpominth's user avatar
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1 vote
1 answer
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Is it safe or reasonable to use the key parameter in a cryptographic hash function as a counter?

Not all the cryptographic hash functions have the counter parameter for making messages be different for each counter value. But many accept a key parameter. Is reasonable to use the key parameter as ...
alpominth's user avatar
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0 votes
1 answer
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How does the public key cryptography algorithm generate a public key based on the private key? [closed]

Because of the need of the project, I want to develop a simple public key cryptography algorithm, but I have doubts when generating the key pair. I have learned about the key generation process of RSA....
SN-Grotesque's user avatar
1 vote
2 answers
71 views

How is asymmetric encryption possible if you need a passcode in order to encrypt something?

Cant you look at the algorithm used to encrypt and find the private key from the public key that way? As an example, here's a simple python algorithm that encrypts an input: ...
Javier Albarracin's user avatar
1 vote
0 answers
45 views

Can new decryption keys be issued without modifying the encrypted contents? [closed]

I'm curious if there's an encryption scheme where content may be encrypted to a public key where the associated private key can generate new decryption keys for the same content. The goal is to ...
Kai's user avatar
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1 vote
1 answer
69 views

Why hashing a seed to generate a key and using chaining to get the rest of key matterial is not secure?

Here, an user says about using a seed to generate a key that is larger than the digest size: "Do not use hash chaining: that's a bad way of constructing a key derivation function from a hash. If ...
alpominth's user avatar
  • 181
0 votes
1 answer
159 views

SPKI Public Key to Compressed Public Key

I currently have a DER-encoded X.509 ECC SECP256K1 public key, also known as SubjectPublicKeyInfo (SPKI) from AWS KMS. How do I convert it to a 66 hexadecimal compressed public key string?
yijie's user avatar
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1 vote
0 answers
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Need clarifications AWS Cloud HSM architecture [closed]

My apologies for the long post. I read on AWS docs that, when keys are generated using java keytool, the certificates are stored ...
arjunballa's user avatar
1 vote
1 answer
36 views

Symmetry shares

I’m sorry if this is already answered, however, regarding symmetric key components to create a symmetric key using xor (So eg comp1 xor comp2 xor comp3 = key) If in the case of an AES KEY, which goes ...
talisman's user avatar
3 votes
0 answers
75 views

AES subkey calculation not working for subkeys beyond 0 and 1

How should I generate the remaining keys when performing subkey generation in AES encryption? I generated keys 0 and 1 first, but the other keys I generated later were wrongly generated, so what steps ...
Mohamed Mohamed Mourad Abdel W's user avatar
6 votes
2 answers
1k views

Always set the IV to 0 randomized CBC

Please explain what goes wrong if we always set the IV to 0 in randomized CBC, and use the system to encrypt two different messages m0 /= m1 with the same key k. I ...
Amirhossein's user avatar
9 votes
2 answers
2k views

How strong are Bitlocker recovery keys?

This is an example of a bitlocker recovery key; 820042-335825-646573-481530-265253-688132-339900-822810 İs that key actually strong? It does not have any letters, ...
asd's user avatar
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1 vote
1 answer
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X509 Client certificate - before - XEnroll / Certenroll / KEYGEN

IBM (now HCL) Domino has since way back a complete procedure to issue X509 client certificate as a login option to a webserver. Back in 2010-ish it worked fine in both Firefox and Internet Explorer. ...
Stefan K's user avatar
0 votes
0 answers
48 views

Client Side Encryption For Web Apps

I want to build something where web clients encrypt some data server side and store it with me. However, I am not sure how to manage the user keys - ideally they can just sign in with social to access ...
CSAMS's user avatar
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0 votes
1 answer
101 views

RSA Key Exchange Attack [closed]

I am curious what is an attack that the RSA Key Exchange algorithm is vulnerable to that Diffie Hellman Key Exchange is not vulnerable to? I know Diffie Hellman is prone to Man in the Middle attacks ...
CryptoGuru's user avatar
1 vote
2 answers
156 views

Keyspace in Encryption using Chaotic Maps

I wish to encrypt an image using Logistic map. A Logistic map can be specified with the Equation: $$x_{n+1} = r\,x_n (1-x_n).$$ Now, according to the Kerckhoff principle, the entire system's security ...
nivedita's user avatar
1 vote
0 answers
114 views

Accidentally leaked my main gpg private key!

I only use one gpg key, which I use with pass, which currently holds a ton of password stuff. I also use that key to sign my github commits and a ton of other stuff....
Hashem A. Damrah's user avatar
3 votes
0 answers
118 views

AES first and last round key whitening

I've found this question from 2014 on Key Whitening: How exactly does key whitening manage to increase security? where is said that AES applies key whitening internally by adding a sub-key prior to ...
LianoQ's user avatar
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1 vote
1 answer
57 views

Can the encryption with CTR mode be replaced by a publicly known unkeyed permutation when doing multiple encryption and keeping the IV secret?

A user of this forum answered in one of my questions and said that if the IV is kept secret in multiple encryption with CTR mode, the cost of breaking the scheme is $${2^{2 l_{key}}} 2 \cdot {2^{l_{iv}...
phantomcraft's user avatar
1 vote
1 answer
43 views

What qualifies as a key?

For my own project and the fun of it I have created an algorithm that turns plain text into cipher by interacting between entered text and a given password. My question is, in this instance, does the ...
vquest's user avatar
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1 vote
1 answer
70 views

Is BLAKE2X suitable for generating keys with any security in bits event if BLAKE2 having only 256/512-bits?

I can generate a key of any security in bits with any hash function from random source with enough entropy by using the following scheme: $$H(00||S) || H(01||S) || H(02||S) || H(03||S) || \cdots$$ /\ ...
phantomcraft's user avatar
1 vote
1 answer
88 views

Encrypting with CBC then XORing repeatedly a chunk of random data smaller than the plaintext: Is there a gain in security?

If I encrypt a 1MiB file with AES-CBC (or any other cipher) and XOR a 128KiB of (truly) unpredictable random data repeating until the end of file, will I have a security of 1048576-bits (128KiB*8)? ...
phantomcraft's user avatar
5 votes
2 answers
2k views

Is it possible to create a pseudo-One Time Pad by using a key smaller than the plaintext?

Let's suppose I want to encrypt a 10GiB file but I don't want to use a One Time Pad, just a 1MiB key taken from /dev/random (in Linux). I know that the key should not be repeated, but is it possible ...
phantomcraft's user avatar
1 vote
1 answer
49 views

Hashing a seed together with a block counter and using as a encipherment scheme: What scheme is more secure in practice?

This question is related to this (but it is not the same). Let's suppose I have a seed with an entropy of 1024-bits and hash it with a counter using a hash function with one-quarter of the seed size ...
phantomcraft's user avatar
1 vote
1 answer
55 views

Signature operation of RSASSA-PKCS1-v1_5 requires private key. Superficial limitation, or are public parameters mathematically incapable of it?

In the case of RSASSA-PKCS1-v1_5, is it simply that the cryptographic libraries and APIs are designed to only sign if determined superficially that it has a private key, or is the public key ...
fartwhif's user avatar
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1 vote
1 answer
55 views

Blom's key distribution

Having a difficult time wrapping my head around the Blom's key distribution. I found an online resource to understand this but still couldn't get it. I am attaching the screenshot from the book where ...
jammy's user avatar
  • 111
1 vote
2 answers
165 views

How much computation it takes to crack a PBKDF2's secret salt when the passphrase meterial has been leaked

Given the following code, extracted from a Bip39 implementation for Android by Zcash ...
zjmo's user avatar
  • 123
1 vote
1 answer
130 views

Standardized names of cryptographic algorithms

I am using micro-services to interact between various cryptographic technologies like HSMs, keystores, vaults, etc., that are written in different languages. Usually, each technology, or even vendor, ...
user1563721's user avatar
1 vote
1 answer
103 views

Hashing a seed together with a block counter and using as a encipherment scheme: Will this have the same security in bits as the seed used?

A user of this forum said that the whole entropy of a seed goes to the hashed result if using a counter and also that is suitable for key generation even if the internal state or digest size of the ...
phantomcraft's user avatar
1 vote
1 answer
78 views

Encrypt messages for two-participants chat

I need a chat between two users and I obviously want to make it as secure as possible. I am, by no means, a cryptography expert, so I turn to you guys for some advice. Because I like the idea of ...
SparxDev's user avatar
1 vote
2 answers
205 views

Is it possible to generate a key from a hash function, being the key larger than the hash function digest output without spliting the seed?

Let's suppose I have a 2MB photo and I want to generate a key from it, and the key should have 2048-bits of size. A hash function such as SHA3-512 would not deliver a key with with the desired ...
phantomcraft's user avatar
2 votes
1 answer
134 views

Streams Ciphers - Linear feedback shift register logic behind design

I’m just seeking a better understanding as to the logic behind design of the A5/1 cipher’s keystream generator. Why are the registers degree chosen in such a fashion (19,22 and 23 bits long ...
Julian Fusco-Wright's user avatar
1 vote
0 answers
30 views

Risk scenarios when hosting KEK in Google Cloud KMS HSM backended [closed]

For some time now, we have been assessing the risks from a GDPR perspective when data (data-at-rest) in the Google Cloud is fully encrypted using native means. This means that we create both the KEK ...
rsfeed's user avatar
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0 votes
0 answers
628 views

Generate SHA256 fingerprint from RSA public key (string only)

I have the public key, the string itself (not a file), and I am trying to figure out the SHA256 fingerprint, as in the image attached. The default key generated by PuttyGen is SSH-2 RSA with a SHA256 ...
user103636's user avatar
0 votes
0 answers
65 views

Storing keys in HSM program flash

We are using an Infineon uC TC233 for a cybersecurity based development. It has HSM but no HSM Data Flash (DF1) present. Our host side application will call HSM APIs itself for any crypto service. ...
user2699785's user avatar
3 votes
0 answers
35 views

Can initialization of the Spritz cipher state by a randomly chosen permutation securely act as a key?

The Spritz cipher is a "sponge-like" construction that the authors show can be used as a hash, MAC, stream cipher, re-seedable pseudo random number generator, and/or an authenticated cipher. ...
cookiecipher's user avatar
2 votes
2 answers
172 views

How to destroy a randomly generated key after using it?

for example, I have an encryption program like this: Input: a message, M; my public key Kpub Step 1: randomly generate a ...
Leo's user avatar
  • 69
0 votes
2 answers
760 views

In a Diffie-Hellman key exchange Find this key and compute the shared secret key k

Hi I struggling to find the answer of my schhol exam, can anyone help me . In a Diffie-Hellman key exchange the multiplicative group of integers modulo p is used with the parameters p = 59, g = 3 mod ...
Yen's user avatar
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-1 votes
1 answer
125 views

What is the importance of superencryption?

Please, can any extensively explain the importance of super encryption in relation to attacks experienced by single standard algorithms
Ubochi Chibueze Nwamouh's user avatar
2 votes
1 answer
109 views

Cryptography methods that allow for multiple keys to be used?

I'm currently working on a webapp in which I'd like all nearly all user data to be encrypted, but accessible by multiple users (ie a doc encrypted should be decrypt-able by parties A, B, C, all ...
cordmana's user avatar
0 votes
0 answers
64 views

Do PQ-KEMs kyber and KEMs approved for 4th round , need Domain Separation?

Do PQ-KEMs Kyber and KEMs approved for 4th round , need Domain Separation for deriving multiple keys from shared secret?
vladmir illusinov's user avatar
0 votes
0 answers
145 views

Is libsodium's Key Exchange system secure?

I'm building a project using libsodium's AEAD + Key Exchange system and want to write a proof justifying the security of the project. I am wondering if I can find a source detailing the exact security ...
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