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.
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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 ...
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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 ...
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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 ...
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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.
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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 ...
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Post-quantum asymmetric encryption algorithms
One could use Falcon-512 for establishing a private and public key for an asymmetric context. Whereas in a symmetric context, we could use firesaber/saber/variants in order to obtain a shared secret ...
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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 ...
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AES Password Based Key Derivation Iterations
I have been writing my own implementation of the Advanced Encryption Standard with cipher block chaining in python3 for the last several months, mimicking the OpenSSL command line interface. I can ...
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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 ...
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How do I encrypt a bunch of messages by different authors, shared with that group of people?
I'm still getting my head around public/private key cryptography, and I can't quite work out how to ask the right question to get an answer for this problem, but here goes!
Alice, Bob, Carol, and ...
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Computing PGP ed25519 and curve25519 keygrips?
There are public key algorithmic differences for how PGP computes fingerprints and keygrips. For the v4 protocol, fingerprints are not exclusively computed from public keys while keygrips are. RFC ...
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Key management in Java + Remembering passwords
I'm new within the area of crypto so I apologise if I am bad at explaining this. So correct me if I've misunderstood anything.
I'm currently developing a Java Fx application that includes the use of a ...
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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 ...
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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 ...
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Multiple Encryption Using GCM For Multi-Key Security
Multiple Encryption For Multi-Key Security
I have a hypothetical question about multiple encryption after reading Matthew Green’s blog on multiple encryption. For those who are familiar with GCM…I ...
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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 ...
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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 ...
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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 ...
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If PGP and GPG both follow the OpenPGP standard, are they 100% compatible in all use cases?
If someone gives me their PGP key, can I use it with GPG, and vice versa, all the time (100% interchangeable)? Or are there times when they are not compatible, when only PGP can be used with a PGP key,...
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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....
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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:
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Revoke a GPG key using previously generated revoke certificate after renewd (change expiration date)
I have few sub-questions
Do secret keys get expired, or just the public key gets expired?
Do I have to back up the master sec key each time I renew it?
For an ...
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Which solution is the more protected?
I am wondering which of these two solutions is better for security on the long run. The problem is:
Alice and Bob exchange a secret key/private key. Then they go far away from each other and never ...
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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 ...
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Cracking a key using a combination of partial keys
As part of a cryptanalytic attack I've carried out, I used a divide-and-conquer strategy to divide the secret key $k$ into several equal-sized partial keys $k = {k_1, k_2, ...}$.
The attack works ...
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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?
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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 ...
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RCON for AES 192 and 256
This is question about how many RCON values are used in AES 192 and 256.
I read the NIST Publication introducing AES and in Appendix A.2 and A.3 (Key Expansion for 192 and 256-bit keys), only $rcon_1$ ...
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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 ...
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Key generation for DH key exchange - benefits of using KMI
Context
We need to generate a key pair in order to perform DH key exchange with the other party.
Some suggest to use a KMI solution (think: AWS KMS or like) in order to generate the key pair.
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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?
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Secure AES Key Generation via Salsa20?
I am not rolling my own crypto or anything - just trying to learn about
the Dos and Don'ts of cryptography: specifically about AES encryption and
ways to generate keys for that.
As far as I've ...
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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 ...
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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 ...
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Is choosing $1$ as a public exponent valid in RSA?
I know it will not encrypt anything. But is $1$ valid as a public exponent in an RSA public key?
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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 ...
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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, ...
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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 ...
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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 ...
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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 ...
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How does biometric authentication add protection to encryption schemes?
I'm wondering since at least 2 offline password management services,Passkeep and Keepass both use biometric authentication in addition to the master password. You need to possess the physical device ...
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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....
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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 $${2^{2 l_{key}}} 2 \cdot {2^{l_{iv}...
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What qualifies as a key?
For my own project and the fun of it I have created an algorithm that turns plain text into cipher by interacting between entered text and a given password. My question is, in this instance, does the ...
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Key Length & Hashing
I need to use a hash function to generate a 128-bit key for a symmetric cipher. The specific cipher is from the eStream portofolio, called Rabbit.
I am using the SRP protocol for authentication (a ...
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Is BLAKE2X suitable for generating keys with any security in bits event if BLAKE2 having only 256/512-bits?
I can generate a key of any security in bits with any hash function from random source with enough entropy by using the following scheme:
$$H(00||S) || H(01||S) || H(02||S) || H(03||S) || \cdots$$
/\ ...
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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)?
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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 ...
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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 ...
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