Questions tagged [encryption]
Encryption is the process of transforming plaintext using a cipher into ciphertext to make it unreadable to anyone except those possessing the key. Decryption is the process of transforming that ciphertext back into plaintext, using the key.
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Long Random Key and XOR - How Secure?
I have an application that encrypts files in the following manner (I think I can hear sighs already but bear with me):
Start with two byte arrays generated from random strings of lengths l1 and l2 (...
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Prove with ZKP that I have encrypted a message $v + random\_number\cdot c$ given an RSA public key?
I want to create an application in which users can cast vote to blockchain in encrypted form using RSA. The private key will be revealed only after completion of the election.
My major use case is as ...
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Is combining Elgamal algorithm and RSA algorithm for key generation and AES+RSA algorithm for encryption and decryption a novel approach?
Key generation: Key Generation
Firstly, the RSA algorithm will be used to generate a public and a private key.
Generate two random prime numbers p, q.
Select RSA public key, P k such that gcd(P k, Φ)=...
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Is this proof of RSA's correctness sufficient?
In a lecture at my university, the following proof of correctness of RSA is given (the lecture is not mainly on cryptography or even computer science):
$m^{ed} \equiv m^{ee^{-1}} \equiv m^{1} \equiv m ...
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Minimal time encryption algorithm for MQTT [closed]
What is the minimal computation time algorithm that I can use for E2E encryption in MQTT protocol which has never been used before
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How to process a message to be embedded using steganography?
Let's say we embed a text using steganography by modifying an existing cover object.
What would be the steps needed to be done on the message?
I can think of
source coding (compression)
channel ...
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Does the Windows RNG have security problems?
The Windows RNG infrastructure is specified in this article.
On page 4, it states that the PRNG called AES_CTR_DRBG is used (with 256-bit security strength).
According to Wikipedia, this PRNG has ...
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May I use the same One-time pad key two times if I encrypt it with a block cipher using two different block cipher keys?
Let's suppose I have two 2GiB files and I want to encrypt them using One-time pad (Vernam cipher), but I don't want to store two big keys.
May I use only one key for the two files if I encrypt the One-...
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How much of SHA3's internal state can be reached?
After reading that about "37% of the 256-bit outputs" of SHA-256 are unreachable when fed only 256-bit inputs [1] I'm curious & confused. The formula from the proof here considers a ...
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PCD vs Recursive SNARK vs Non-uniform IVC
I was wondering if anyone could clarify the differences between PCD vs Recursive SNARKs(like pickles) vs Non-uniform IVC(like hypernova)
They all seem very similar to me
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Fully-encrypted (non-fingerprintable) symmetric encryption algorithm?
I am a student in the process of creating a firewall circumvention program based on smuggling data inside of legitimate HTTP. I have limited cryptographic knowledge.
I need a way to encrypt my higher-...
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Does compressed data expose information about non-compressed data when encrypted together?
I know that compressing data before encrypting it can cause a compression oracle attack such as in the CRIME and BREACH attacks, but if only part of the data is compressed, e.g. non-user controlled ...
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How CTR mode is encrypted?
I referred to the explanation of encryption mode from Wikipedia, but I'm confused now, and I went to find some books about Cryptography, but it didn't solve my confusion.
The CTR mode uses Counter to ...
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Is private key generation without prior communication possible in naive RSA?
From what I have understood of naive RSA (without padding) so far, it seems that A and B must first decide on the prime factors in order for B to generate its private key to decrypt A's message.
I do ...
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Threshold encryption
Is there any (k,n)-threshold encryption scheme, such that the decryption process is non-interactive, i.e., the decryption can be processed "in a line" where each party "in the middle of ...
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Regev's learning with error
If we talk about the security of public key encryption in Regev's lwe system, if attacker would have knowledge of $(u,u'):[\mathbf u=A\mathbf r, \mathbf u'=\mathbf b^t\mathbf r + \mu q/2, \mathbf r\in\...
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Security of keys that are as long as the data
If both communicating sides end up with the same secret 3000-bit key, is it enough to XOR each byte of the messages with each byte of the secret key to make it secure?
Wikipedia says it is, but I ...
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Is Python secrets module using a unsafe RNG on Windows?
The Python secrets module claims to produce cryptographically secure random numbers. I did some research on which random number generator is used when you call the secrets module on Windows. I found ...
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Is it possible to have a shared secret between an unlimited number of parties asynchronously?
Let's say I encrypt a message with some secret and store it in a database. Later, I want to securely share that secret with someone, so that they can read the message as well. Even later, I want to ...
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What is simple asymmetric encryption that use arbitrary key?
While XOR is used as simple symmetric encryption with arbitrary custom key, what is a simple asymmetric encryption that use arbitrary custom key?
That means I want to be able to set custom private key ...
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If I encrypt a plaintext with different keys for each block, will I have the same security as a one-time pad?
Let's suppose I encrypt an 1MiB plaintext with AES-256 in ECB mode but using different keys for each 16-byte block (I know this is weird but it's just an example).
Remembering that a different 256-bit ...
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Combining decryption function with transformation in a way that can't be reversed
I have a program implementing a function $f$, and want to find a pair of functions $e$ and $h$ such that $h \circ e = f$, but $e^{-1}$ cannot be recovered from $h$.
In other words, given some $e$-...
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Why the Modulus and Exponent of the public key and the private key are the same?
Given a certificate .p12 I want to extract the public key, the private key and Modulus and Exponent both from the public key and from the private key.
I am using PHP and OpenSSL functions
As I ...
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Encrypt different inputs with different keys to obtain the same output
I'm researching to see if there is an algorithm that encrypts different inputs with different keys to produce the same output.
So let's say I have 2 messages.
...
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Genrerate n numbers based on a string [duplicate]
I wanna generate a list of numbers based on a unique string. They shouldn't be predicatble and every time to generate they are the same.
Could someone help me pleeease :)?
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How to require possession of arbitrary data to decrypt a file?
I have pairs of files A and B both of arbitrary size and contents (for any pair of files, A could be significantly larger than B or vice versa). I want to be able to 'encrypt' A in such a way that I ...
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How to extract a private key from .PFX file to .PEM file using AES-GCM as a password-based encryption?
I'm trying to extract a private key from a .PFX file to a .PEM file format. I was able to do it using Aes128Cbc in either .NET or OpenSSL:
.NET:
...
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How to prove the correct decryption of several (ElGamal) ciphertexts in a batch？
I know how to prove the correct decryption of a (ElGamal) ciphertext.
The above protocol is from the paper: Bootle J, Cerulli A, Chaidos P, et al. Short accountable ring signatures based on DDH[C]//...
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If we supply a random uuid4 hashed salt to Hashid, will it be considered secure?
Ideally, Hashids -: https://pypi.org/project/hashID/ are considered insecure and it is recommended that we should not use them for any sensitive functions. Though, is a HashId considered secure if we ...
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If encrypting with a hash function in counter mode, will the security of this scheme be at most minimal{input,output}?
It's possible to use a hash function as an encipherment scheme if used in counter mode.
Let's suppose I take a 64-bytes (512-bits) seed/key and hash it concatenated with counters, and use it as a ...
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Is AES worse than OTP, if so is there proofs
My train of thought went, OTP is very secure if key is unknown because I am guessing the original message. AES on the other hand tells me I gave it the wrong key, and if I did I can just switch using ...
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Can we extract public key from signature created by RSA?
I know it's possible with ECDSA. How bout RSA?
warnerque
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Symmetric and asymmetric encryption using the same encryption/decryption algorithm?
If we use the following notation:
$$C = E(P, K_e)$$
$$P = D(C, K_d)$$
Where:
$$E(), D(), C, P, K_e, K_d$$ are the encryption algorithm, decryption algorithm, ciphertext, plaintext, encryption key and ...
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How do I decrypt a key encrypted by my HSM under a ZMK?
I've generated a key using an HSM Thales PayShield and i have share it with a counterpart. I followed these steps:
i generated key usign KG console command
i use FK to form ZMK from clear components ...
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How to find the round key in AES 256
Can anyone explaine how to find the every 15 round key by the 64 hex digit master key of AES 256 please. I will be really greatfull
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Are asymmetric encryption and decryption same function? [closed]
In asymmetric key encryption, we have 2 functions, encrypt(m,k) and decrypt(m,k), and 2 keys, ...
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Is there a multi-key encryption and decryption algorithm that allows key revocation?
I have private data and I want to encrypt it to share it with some users who should be able to decrypt it. Therefore, I need multiple keys to decrypt it. But, I also want to be able to revoke a key to ...
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Securely computing the addition of n numbers owned by n people
Assume that we have n people each owning a secret number. Now we want to collaboratively compute the addition of all these numbers without anyone revealing their numbers. Then the result will be made ...
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Why is static-static diffie hellman needed in Noise_IK?
TL;DR: Why is there a static-static diffie hellman in the Noise_IK handshake?
Hi,
I am currently trying to understand the WireGuard VPN protocol.
As you may know, it uses the Noise_IK handshake from ...
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How many ciphertexts should attacker intercepts if he only knows the first 3 bytes of plaintext of each one?
Consider a system in which DES is used to encrypt messages in which the first three plaintext Bytes are known by the attacker. How many encrypted messages is it necessary to intercept in order to be ...
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Stuck on Decrypting with RSA and SHA256 in Encryption Task
I'm working on solving a encryption task, and I'm a bit stuck. I want to clarify that I'm only seeking hints and not direct answers since I want to solve it myself. The goal is to solve it on my own; ...
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Secure encryption in the presence of a keyservice
Imagine this scenario:
On a particular PC is a service that provides cryptographic functions -- in particular AES-CBC and ECC (ECIES/ECDSA).
The service provides access to a single key stored in an ...
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How does TLS 1.3 restrict the Diffie-Hellman parameters to ones that are known to be secure?
In previous versions of TLS, the choice of the Diffie-Hellman parameters was up to the participants. This resulted in some implementations choosing incorrectly, resulting in vulnerable implementations ...
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Threshold Paillier encryption key generation time
I have used the threshold version of Paillier encryption without a trusted dealer in an application. I have tested the key generation phase with different security key sizes such as 80, 512, 1024, and ...
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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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AES CBC with random IV but key from PBKDF2 with same salt
TL;DR: Is encrypting data with AES CBC with random IV + PBKDF2 key using the username as salt safe?
I have searched the internet, but I could not find a proper answer that encompasses the "AES ...
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Enigma Questions: Eliminating the can't encode to itself flaw? Maybe not a flaw
I am currently writing a paper in my old age for the fun of it. I feel that the enigma machine had gotten a bad wrap for some of its flaws. I decided to write a machine simulation to see if I can ...
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Forming ECC key (TLS) in X9.63 format
I am studying TLS handshaking by example a program tlse, which uses libtomcrypt library.I see that in line 5236 (link above) the program call libtomcrypt procedure ...
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Cryptography particular block length valid message
I am new at cryptography and start to learn some terms. I just saw an question in the book and didn't got a clue about this question. Could someone can explain me the answer of this question? Because ...
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Are passkeys actually hardware keys or are they just reversibly encrypted keys secured by a hardware key?
Passkeys have this complicated QR code + Bluetooth dance to enroll a new device which seems like it ought to be securely creating a key on the device in a TPM.
However the messaging around "sync&...
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