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.
273
questions
1
vote
1
answer
79
views
Deliberate error in decryption by modifying the encryption
Are you aware of any cryptosystem in which the following is doable:
The sender of information can deliberately manipulate the encryption process such that some controlled error is produced in the ...
- 11
0
votes
0
answers
29
views
Is it possible to execute a plaintext attack on a slidefair cipher
there.
Ive got the cipher text: GKFJMNMJLRHLJKSMPFLMYCS
And an answer: EEADIHHHJFEFHENGLZGKWQP
The person that encrypted this ...
0
votes
0
answers
31
views
How to break a Vigenère cipher with a partial plaintext and key?
I have an question regarding Vigenère decryption. Is it possible to break a Vigenère with a partial answer key?
Ive got the cipher text: GKFJMNMJLRHLJKSMPFLMYCS
And ...
0
votes
0
answers
42
views
Proof of Decryption in a Chinese Remainder Theorem-Based Encryption Scheme
I've been studying a cryptographic scheme that uses the Chinese Remainder Theorem (CRT) for decryption. Here's a brief overview of the encryption and decryption process:
Setup:
Alice chooses two ...
- 1
1
vote
1
answer
64
views
lattice RLWE encryption and decryption process
I am here trying to solve an issue that I face a lot during solving RLWE.
The issue is that I am not able to retrieve the original message after the decryption process.
I use the following encryption ...
- 33
2
votes
2
answers
176
views
Cryptography elements requested for a plot in a story
experts. I am working on a story that involves a terabyte portable drive that has been encrypted by Person 1 and needs to be decrypted by Person 2 (Person 1 is deceased by that point).
Person 1 and ...
- 21
0
votes
0
answers
60
views
Parallel block cipher in CTR mode and variable number of threads: how to deal with internal state and permit decryption?
I'm implementing a parallel block cipher (Morus, to be precise) in CTR mode and I'd like to make it flexible with respect to the number of threads. It is not difficult per se, as I can partition the ...
- 101
1
vote
1
answer
187
views
Can the RSA public key be used for both encryption and decryption?
My understanding of RSA Cryptography is that the Public Key is used for data encryption and Private Key is used for data decryption. But on this website(https://www.devglan.com/online-tools/rsa-...
- 113
1
vote
3
answers
140
views
Why do we need more security than the private key distribution?
I'm new to cryptography and have question about private key distribution. If we are able to send private keys to the encoder, then it means that we are able to send private keys to someone, which ...
- 113
0
votes
0
answers
56
views
What is a generalized algorithm to find five $z$-bit words for the inverse of $\theta$ function in the Keccak-$f$ permutation?
This implementation of the inverse of the Keccak-$f$ permutation contains five 64-bit words (called “inversePositions64” in the code) for the inverse of $\theta$ function:
...
- 1,367
1
vote
1
answer
80
views
"Appendable" encryption scheme
Are there any encryption schemes that could be classified as "appendable"?
By appendable I mean being able to add new data to the end of already encrypted data, without needing to decrypt ...
- 11
0
votes
1
answer
84
views
Question about error-Correction Code on Paper titled 'A New Public-Key Cryptosystem via Mersenne Number"
I've been implementing a cryptosystem outlined here, which relies on Mersenne Numbers, as part of my coursework in a Cryptography class.
In this cryptosystem, both encryption and decryption require ...
- 11
0
votes
0
answers
74
views
Reaching the bound of Boneh and Durfee Attack
According to the paper, theoretically,we can get $\delta=0.292 \lt 1-\frac{1}{\sqrt{2}}$,but how to set the lattice and implement it in sagemath? I generated some data
by
...
- 1
0
votes
0
answers
42
views
Decrypting Message Using One-Time Pad with Repeated Key [duplicate]
I'm trying to decrypt a message that has been encrypted using a one-time pad with a repeated key. The encryption technique involves using the same key twice. We know the message was encrypted with $k =...
0
votes
2
answers
209
views
Is it possible to perform reverse rsa encryption ? (using the public key for decrypting and the private key for encrypting)
Simple question, but I couldn’t find an answer as I know about signing but don’t want it.
The aim would be to encrypt someone’s bet parameter as a short message using the private key and use the ...
- 240
0
votes
0
answers
126
views
Homomorphic Decryption with the Encryption (ciphertext) of Secret key for Bootstrapping purpose
The section 3.1 of the GHS11 mentions that:
Given the $q_L$-ciphertext $c = (c_0, c_1)$ (that encrypts a polynomial $a \in F_2[X]/F(X)$), we postprocess it to get $c^\prime = (c_0 + c^*, c_1) \text{ ...
- 11
3
votes
2
answers
1k
views
Can I change the radio frequency according to my encryption algorithm?
I know that information can be changed by changing the frequency of electromagnetic vibrations.My question is, can I change the frequency according to my encryption algorithm? That way I can get a ...
- 33
0
votes
1
answer
63
views
Cartesian Product Notation for Encryption and Decryption
I'm learning about encryption $(E)$ and decryption $(D)$ algorithms and am wondering what the following notation means, specifically the cartesian product for $E$ and $D$.
$k$ represents key, $P$ ...
- 103
2
votes
1
answer
413
views
Decrypting 3 Binaries | LFSR
I have three binary arrays each one representing the pixels of an image. For example, if the picture size is 100 pixels X 100 pixels. Then the binary array would be 100×100×8×3 bits. These files are ...
- 21
1
vote
2
answers
367
views
Is it faster to decrypt than to encrypt in all cryptography systems? [closed]
I am using a cryptography system in which the Feistel structure and permutation cipher are combined. I am amazed by the result; decryption is so much faster than encryption. My system is working ...
0
votes
0
answers
234
views
Speed comparison of encryption algorithms
I am trying to compare various encryption algorithms in terms of encryption duration, decryption duration, information entropy, NPCR, UACI, and correlation coefficients.
I used a Lena 256x256 ...
- 1
0
votes
0
answers
118
views
Finding bit positions of '1' in DES Encryption
In DES encryption, the IP table is shown. If the input
given in hexadecimal is "0020 0940 0000 F008", which
are the bit positions of "1" after the IP stage ?
0
votes
0
answers
102
views
Finding plain text given two cypher texts of the same plain text with two different public keys
I want to find the plain text from two cyphertexts of RSA, encrypted with two different public keys. I know that: for $E((n,e),m) = c_0$ and $E((n,f),m) = c_1$ , $c_0^x \cdot c_1^y \bmod n = m \bmod n ...
- 1
-1
votes
1
answer
120
views
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 ...
0
votes
1
answer
108
views
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 ...
0
votes
1
answer
146
views
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 ...
0
votes
0
answers
122
views
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....
0
votes
0
answers
23
views
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 ...
- 1
0
votes
1
answer
157
views
What is the inverse of this variant of the Gimli SP-box?
Consider a slightly modified variant of the Gimli SP-box:
...
- 1,367
1
vote
1
answer
169
views
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{...
- 1,367
0
votes
1
answer
72
views
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 (...
- 1
0
votes
2
answers
154
views
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 ...
- 153
1
vote
1
answer
85
views
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 ...
- 51
3
votes
1
answer
696
views
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 ...
1
vote
0
answers
42
views
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
2
votes
3
answers
637
views
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.
...
- 123
0
votes
1
answer
68
views
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, ...
- 9
2
votes
0
answers
40
views
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 ...
- 143
1
vote
0
answers
96
views
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 ...
- 11
1
vote
1
answer
145
views
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 ...
0
votes
1
answer
230
views
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 ...
- 371
0
votes
1
answer
61
views
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 ...
- 123
1
vote
1
answer
473
views
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 ...
- 11
2
votes
1
answer
1k
views
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 ...
- 23
1
vote
1
answer
140
views
RSA - plaintext equal ciphertext
Just started learning about RSA cryptography so forgive me if I made any mistakes or misunderstandings.
...
1
vote
0
answers
659
views
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 $2^...
- 33
5
votes
1
answer
517
views
Where does signing/decrypting take place on a YubiKey 5 for PGP private key?
I have found similar question for PIV (and not PGP)
I assume PIV and OpenPGP would work in similar ways. I also assumes that the GPG private key never leaves the Yubikey.
If these assumptions are ...
- 53
0
votes
1
answer
174
views
Differential trails in differential cryptanalysis
From section 4.4 of this book https://www.ic.unicamp.br/~rdahab/cursos/mo421-mc889/Welcome_files/Stinson-Paterson_CryptographyTheoryAndPractice-CRC%20Press%20%282019%29.pdf
I'm confused on how the ...
0
votes
0
answers
784
views
Cracking 2-Key Triple DES
I've been given that an attacker has a 2-Key Triple DES Cracker that is capable of performing 10$^{24}$ encryptions per second and have subsequently been asked how long it must take before the ...
- 101
0
votes
1
answer
107
views
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.
...
- 31