Questions tagged [decryption]
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Only authorized parties can decipher a ciphertext back to plaintext and access the original information.
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Is it possible to deduce the input of a hash by running in reverse? [duplicate]
If i understand correctly, hashes run a defined set of operations iteratively until the original data is all hashed.
Can you take a hash value, run it backward through the last step (or once, for an ...
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Is it possible to detect Stealthy False Data Injection attack through chaotic cryptography?
I am doing a research on detecting Stealthy False Data Injection (SFDI) attacks in a smart grid context (a related paper). Besides I am working on a chaotic cryptography (e.g. with Lorenz attraction) ...
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Does higher key sizes correspond to a higher security parameter?
If a system provide n bits of security, it is known that the best possible attack against the system would be 2^n (security parameter).
However, why are the key sizes of some cryptosystems much larger ...
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Syndrome Computation Patterson's Algorithm
Suppose in Patterson's algorithm for the correction of binary Goppa codes, we wish to compute the syndrome polynomial when the defining polynomial is $g(x) = x^{4} + x + 1$, and the error polynomial ...
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Enigma - Bombe - Understanding the relative values of ring settings to key settings
For a project, I am writing Enigma and Bombe simulators in Python.
I have coded up both and so far so good.
My Enigma simulator gives the same results as the online simulator here:
https://people....
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Decrypting AES-128 with known regularly spaced single byte value [duplicate]
How would knowing a clear byte value of the decrypted data affect a brute force attack on an AES-128 encrypted message ?
i.e. If I knew the 1st byte should decrypt to 0xff
OR I knew that every 100 ...
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What is the inverse of this variant of the Gimli SP-box?
Consider a slightly modified variant of the Gimli SP-box:
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What is the inverse of this generalised automaton (based on bitwise XOR and modular addition)?
Section 4.1 of the paper “Nonlinear Diffusion Layers” [Y. Liu, V. Rijmen, G. Leander] defines the nonlinear function $\rho$ over $\mathbb{F}_{2^m}$ as follows: $$\rho : \mathbb{F}_{2^m}^4 \to \mathbb{...
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Does BearSSL Library Support ECC Encryption/Decryption Functionality?
I'm researching cryptographic libraries for a project I'm working on, and I'm particularly interested in the BearSSL Library due to its lightweight nature. But I'm not sure if it supports ECC (...
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From Entropy's perspective how Encryption affects a Message?
How Ciphers, specifically, Substitution Ciphers and Transposition Ciphers manipulate the Entropy of Plaintext w/wo the aid of Entropy Source?
Reversely, how Decryption manipulates the entropy of ...
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Ensuring Data Security During Decryption and Re-encryption Process
Scenario:
Consider a scenario where Server 1 stores a 600-800 KB ebook encrypted with a certain private key. Server 2, a computation-purpose server, holds this private decryption key and get access to ...
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On real-time decryption of encrypted radio communications
According to Jack Watling & Nick Reynolds,
Ukrainian officers recalled one incident in which the Russian headquarters gave pre-emptive warning to its units of an artillery strike based on ...
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Vigenère cipher SECRET
Decrypt “jjjj aaa cccc ddddd” using Vigenère cipher with the key “CONVO”. I used 2 different generator and online calculator and i am getting 2 different results
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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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Why is decryption algorithm usyally deterministic?
For security against Chosen Plaintext Attack (CPA), we need randomized algorithms for encryption. But in some schemes (maybe almost all of them) take decryption algorithm deterministic. This procedure ...
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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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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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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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XTEA-based encryption to handle up to 128bit block size [closed]
As learning to be an electronic engineer, my lecturer has requested, based on the original Xtea, to develop the FPGA solution to run 128-bit block size and 128-bit key size cryptography. I have ...
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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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If ChaCha20 only has 128 bits, is it secure?
ChaCha20 also provides 256-bit encryption, i.e, 2^256 possibilities of keys. But ChaCha20 is very fast, I think it provides at most 2^256 multiplied by decrypting time. 256-bit AES provides 254-bit ...
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Why is IV in RFC8448 examples only 12 octets instead of 16?
I am working on manual decryption of application data in TLS 1.3 by going through example in RFC8448. I successfully derived and expanded key and IV, but the IV in examples is only 12 bytes long ...
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Can I use Argon2 to encrypt data?
Normally I use Argon2 to generate an encryption key, and then use AES to encrypt data with that key.
Can I just set the hash size to be equal to the data size, set the associated data to a random ...
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Padding Oracle Attack - Decrypting First Block with Static IV
I'm trying to understand the exploitability of the padding oracle attack, which enables someone to decrypt and encrypt the contents without knowing the encryption key.
Can encrypted data with the ...
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RSA - plaintext equal ciphertext
Just started learning about RSA cryptography so forgive me if I made any mistakes or misunderstandings.
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How can I decrypt a message with RSA if $e = 65536$ and $\gcd(e,\phi(N)) = 8$?
In a message exchange with RSA, an unusual public exponent $e = 65536$ is used.
Since $N$ is easily factored, I am able to derive $p$ and $q$. Consequently $ \phi(N) = (p-1)*(q-1)$.
However, since $2^...
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Where does signing/decrypting take place on a YubiKey 5 for PGP private key?
I have found similar question for PIV (and not PGP)
I assume PIV and OpenPGP would work in similar ways. I also assumes that the GPG private key never leaves the Yubikey.
If these assumptions are ...
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RSA decryption given C (Cipher Text), e, and d [duplicate]
I am given C, e, and d to decode an RSA ciphertext (or would it be SRA given this information?), and I am thoroughly confused. I have tried working backward to n by reversing modulo operators and then ...
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Differential trails in differential cryptanalysis
From section 4.4 of this book https://www.ic.unicamp.br/~rdahab/cursos/mo421-mc889/Welcome_files/Stinson-Paterson_CryptographyTheoryAndPractice-CRC%20Press%20%282019%29.pdf
I'm confused on how the ...
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Cracking 2-Key Triple DES
I've been given that an attacker has a 2-Key Triple DES Cracker that is capable of performing 10$^{24}$ encryptions per second and have subsequently been asked how long it must take before the ...
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Unable to retrieve the binary string using LWE and Lattice-based decryption
I am new to this encryption scheme, so I may not be exactly sure of its implementation.
I have a list of (u, v) ciphertext pairs to decrypt, each of them are 1-bit.
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LWE and Lattice-based cryptography: How to recover binary message $M$ from $(u, v)$ values?
I am given a set of $(u, v)$ values, matrix $A$, primary key vector, private key vector, error vector and prime $q$. I wanted to recover the binary value of each $(u, v)$ pairs using LWE decryption.
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Would it be technically possible to use hundreds of computer processors together to work on an algorithm like the Shor's algorithm and break RSA?
Would it be technically possible to use hundreds of computer processors together to work on an algorithm like the Shor's algorithm and break RSA?
I've been reading about the crazy amount of qubits ...
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Problem in matching AES CTR encryption and decryption with two different engines
I have a problem in combining encryption with a host software tool based on LibTomCrypt sources, then decryption with the hardware BEE (Bus Encryption Engine) of an i.MX RT1062 NXP processor. I am ...
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Implementing AES GCM but not getting correct output from cipher block
I'm implementing 128-bit AES-GCM (but only the encryption/AES-CTR aspect).
When I set the Secret Key, Plaintext and IV to Test Case 2, page 27 of the GCM spec (see below) I get the wrong value for the ...
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AES GCM Difference between the IV and the Secret Key?
Below is part of AES GCM diagram. However, it only shows the behavior of the IV/counter.
The GCM specification examples state both an IV and a Secret Key as two inputs.
Can someone please explain ...
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What is Inverse equivalent (decrypt) in the AES specification examples?
Referring to the AES specification:
https://nvlpubs.nist.gov/nistpubs/fips/nist.fips.197.pdf
Printed pages 35-37...
The first detailed walkthrough is encryption, the second is decryption.... I don't ...
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Reencrypting in Homomorphic Encryption
I am getting started with Homomorphic Encryption libraries. I am trying to port a codebase written in Python to Haskell. I see that there is a re-encryption operation happening in one part of the code....
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Is the XOR two block ciphers still a block cipher?
Let's say I have a block cipher $E: K \times M \rightarrow C$.
Is the function defined by $\operatorname{Enc}(k_1,k_2,m) = E(k_1, m)\ \operatorname{XOR}\ E(k_2,m)$ guaranteed to have an inverse ...
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Designing a scheme to store encrypted data on a backend
My goal is to design an encryption scheme for the application so that the backend stores encrypted data and the whole process of encoding and decoding happens on the frontend. And you can be sure that ...
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Curious about CCA attack for RSA, and Kerckhoffs's principle in general
I'm a student studying cybersecurity for the first time, and the part where our textbook explains using CCA attacks for RSAs seemed really unclear for me, so I am here seeking for clarification.
Our ...
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How to decrypt a RSA plaintext given a public exponent e and a RSA modulus n
I am doing a RSA cryptography task where I need to decrypt a ciphertext but I am only given the ciphertext ,c, a public exponent, e, and a RSA modulus, n, which has two prime factors p and q such that ...
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Possible plain text needed on a congruence modulo - based encryption
Suppose m is a positive integer converted from the plain text in bytes.
And there are two positive integers a, ...
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AES Decryption - Expand Key/First Roundkey
I am wondering how to use and expand keys during the Decryption.
Let’s say we have an initial key (128bits): 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F 70
So we get: w[0] = (61 62 63 64), w[1]=( ...
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'str' object has no attribute 'decode' when decrypt aes [closed]
so i have function to decrypt aes ctr. but when i tried to decrypt, the result i got from plaintext is type bytes. i want to get the result of plaintext using decode, because when i encrypt it, i was ...
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Block cipher decryption
I have a course work for university.
The question is:
My solution to the question is:
P||R = D(K,C)
However, in the question it doesn't say we are given R so ...
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Does file size significantly affect brute-force time?
Suppose you have two files encrypted with AES-256. One of the two files is 5MB, the other one is over 1GB. Their passwords are reasonably strong: >12 characters, letters, numbers, upper and lower ...
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How are public and private keys generated and used for encryption and decryption in a lattice based cryptosystem?
I've recently become quite interested in lattice based cryptosystems, and I wish to understand them more deeply. I have only a rudimentary understanding of the shortest vector problem (SVP), and its ...
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Zero knowledge validation to check if private element is in a set hidden on a central server
I am trying to determine how to apply ZK proofs to the asymmetric scenario below.
Say there is a list of 5000 secret elements on a centralized web server.
Users are trying to guess what those 5000 ...
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Reversing an XOR encryption/decryption function
I have a help recommended high-school project that I'm stuck with. To basically explain the problem: I have an encryption function that is used as the decryption function and I need to reverse it to ...
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