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.
4,651
questions
0
votes
0
answers
20
views
Can't figure out the encryption [closed]
The ciphertext:
Fubswrulqwb lv wkh sudfwlf dqg vwxlv ri whvwlf ryhu wklv xvhvwlq ri dwhvhvhfuhv ejwhfq. Pruh jovqshq, fubswrulqwb lv deyqxbuwlqj dqg exsduqbg rqrq ykiwhk vdssrkwxmtqj dqg wkhslnkrdq ...
0
votes
0
answers
43
views
How to prove that signature hash is wrong without reveal message
Let's say we have Bob, Alice and third party.
Bob make message signature hash and upload to third party, then encrypt message with Alice pub key and send it to Alice
Alice receive message and decrypt ...
- 3
0
votes
1
answer
100
views
Possible to encrypt message without knowing recipient public key?
Assume Bob is sender and Alice is future recipient.
In ideal situation Bob know Alice public key, and encrypt message with it.
But what if Bob don't know Alice public key (he only will know Alice ...
- 3
0
votes
0
answers
37
views
which DH protocol is safer in communication with given condition?
I am trying to understand some concepts such as DH problem and its variants. I have the following question from the book I read. (note that I translated the question from my language to english)
...
user112930
1
vote
0
answers
45
views
Input/Output size of compression functions
I know that DES has 56 independent key bits, and that 3DES has 168 independent key bits by using 3 seperate 56-bit DES keys. 3DES also has a block size of 64 bits.
If I use 3DES as the underlying ...
- 11
0
votes
1
answer
44
views
Safety of using non-encrypted hashes to identify encrypted data in a key-value store
I saw posts tangentially related to this, but not this one specifically.
I'm building a content-addressable storage layer where I'd like to store the contents encrypted. The question is what is a safe ...
- 101
0
votes
0
answers
27
views
Where on Stackexchange could i post work on new factoring methods [migrated]
What board can i post work showing original framework for factoring methods, so that i can get insight from others with more expertise on why such a framework functions? I have some understanding now,...
2
votes
0
answers
79
views
Source of encryption scheme used in blockchain based IoT
I've found the following encryption scheme
UserA: $$sk_A, pk_A = sk_A \cdot G$$
UserB: $$sk_B, pk_B = sk_B \cdot G$$
Enc: UserA
$$u \in \mathbb{Z}_q^* \\
Y = u \cdot pk_B \\
S = H(U) \oplus m \\
C = (...
0
votes
0
answers
49
views
ElGamal signature scheme problem and unsure whether my calculations are wrong or that's the answer
Trying to solve problem with verifying a message through the ElGamal signature scheme and I end up getting two different values.
I'm given a prime number p=881
, e1=3,
d=60
, and a random value r=11
. ...
- 1
1
vote
0
answers
30
views
Assistance required with a suspected Nihilist Cipher text associated with a 1948 Cold Case [closed]
I have found a cipher text that shows up as a Nihilist Cipher when entered into the dCode cipher identifier. The text was found in a torn slip of paper bearing the words TAMAM SHUD, the last two words ...
2
votes
1
answer
109
views
Does combining a stream cipher and block cipher produce any vulnerabilities?
In particular, AES-CBC with Blake2b for HMAC combined with xChacha20-Poly1305.
The scheme is to encrypt with xChacha20-poly1305 first, using a key derived from a high entropy password using argon2id ...
- 21
-2
votes
0
answers
56
views
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) ...
rgholizadehr
0
votes
0
answers
83
views
Decrypt RSA knowing N, invp, and invq
im having a problem while solving a RSA problem, so i have python script to create a RSA key and cipher, from that i have n, invp, and invq. so my question is possible to decrypt the message only with ...
- 1
0
votes
1
answer
103
views
Does using multiple encryption algorithms with different keys on the same cipher text improve security?
I'm looking for maximum possible security. My current scheme is xChaCha20-Poly1305-xSalsa20-Poly1305-AES-CBC-HMACSHA-512. Does combining these algorithms increase security if implemented correctly? ...
0
votes
0
answers
38
views
Is it secure to encrypt an authentication token using another possibly hashed authentication token?
I'm working on a web app ("main") which acts as a central access hub for several other web apps ("children"). The users are supposed to authenticate in the main app, resulting in a ...
- 101
1
vote
1
answer
78
views
Is gcd(e,p−1)=1=gcd(e,q−1) similar to gcd(e,phi(n))=1?
I wonder, is $\gcd(e,p−1)=1=\gcd(e,q−1)$ similar to $\gcd(e,\phi(n))=1$ ??
- 11
0
votes
1
answer
40
views
Does the use of a passkey (FIDO) link your physical device id, eg IMEI, to that specific passkey?
Passkeys are being introduced.
From what I understand so far, a passkey involves the storage of a private key, and retention of a public key with the internet service. Eg Google, Apple, Microsoft, ...
- 103
0
votes
0
answers
46
views
In RSA Encryption, Can I choose the public exponent e > m (modulus) ? or e > φ(n)? [duplicate]
In RSA ,the encryption, Can we choose the public exponent (e) greater than m (modulus) or e > φ(n) ? I wonder about choosing public key exponents (e) because the most information on the internet or ...
- 11
0
votes
1
answer
95
views
Hybrid key exchange in TLS 1.3
In Hybrid key exchange in TLS 1.3, they mention that with a hybrid approach, we concatenate the shared secret from each method (say KEM like Kyber768 + classical ECDH X25519 = X22519Kyer768).
...
- 147
0
votes
0
answers
39
views
Is using a CPA secure public key encryption twice on two halves of the message with different keys secure?
If $\Pi=(\mathrm{Gen},\mathrm{Enc},\mathrm{Dec})$ is a CPA secure public key encryption protocol, is the following public key encryption CPA secure?
$\Pi'$:
$\mathrm{Gen'}$: Run $\mathrm{Gen}$ twice ...
0
votes
0
answers
47
views
In RSA Encryption, Can the public exponent e > m (modulus) ? and can we choose any public key without paying attention to the conditions? [duplicate]
In RSA ,the encryption, Can we choose the public exponent (e) greater than m (modulus) or e > φ(n) ?
I wonder about choosing public key exponents (e) because the most information on the internet or ...
- 11
0
votes
1
answer
94
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 ...
1
vote
1
answer
77
views
Construction of Blake2 and Cha Cha
Recently, I was reading about Blake2B and its properties regarding randomness and security, and its connection to Daniel Bernstein's CHA CHA digest. As a budding cryptographer, I find it doable to ...
- 11
2
votes
1
answer
109
views
Password Manager Architecture and Design
I'm working on a local, client-side password manager. I want to hash a master password with argon2 to store it safely in an SQLite database. This will be how a user could login and be authenticated. (...
- 123
0
votes
0
answers
28
views
Using asymmetric encryption + key rotation, is it possible to make an extra obfuscation layer?
I'm building a service, that works as the cipher and decipher for instant messages. It works by following the following steps:
The sender encrypts the text(not long, mostly chatting messages) using a ...
1
vote
0
answers
65
views
Weaknesses of AES-GCM [duplicate]
Besides the limited nonce size of 96 bits, are there any other weaknesses to the GCM mode of AES?
I am creating a password vault and am trying to narrow down my options of encryption schemes.
Also, is ...
- 11
1
vote
1
answer
160
views
Cryptography to tackle deepfake, proving the photo is original
Deepfake technology has become very difficult to tackle due to sophisticated machine learning algorithms. Now, even when a journalist or bystander provides photo or video evidence, the culprit denies ...
- 111
0
votes
0
answers
50
views
AES-ECB attack encryption audio fie
I got two audio files one is encrypted and the other file is a part of the plaintext. I want to extract all the plaintext. I am using the AES-ECB mode, the size of the block is 128 bits and the start ...
3
votes
1
answer
250
views
Is there any way to measure entropy of encryption algorithms in python?
I am new to cryptography and I am trying to find a way to measure ciphertext entropy of encryption algorithms such as AES, Chacha20, etc for a school project. Is there any way to do it on Python? I ...
- 43
0
votes
1
answer
65
views
Is it possible for XTS to use two different key sizes?
As an example could be XTS with a 512-bit key that treats the key as one 128-bit key and one 348-bit key.
As to why I'm asking it's because XTS runs on one large key that it treats like two keys. ...
2
votes
0
answers
61
views
Can someone help me in construction of a one time unconditionally secure MAC scheme? [closed]
The MAC scheme should not be using any primitives like PRG, PRF or PRP. Ok what could be possible solution if we ignore the statement "
- 21
2
votes
1
answer
110
views
Why is the adversary in IND-CCA allowed to make encryption queries?
IND-CCA is an abbreviation of "Indistinguishability under chosen ciphertext attack" and generally, an adversary carrying out the chosen ciphertext attack is given a decryption oracle only. ...
- 23
0
votes
2
answers
72
views
Is signature same as hash value encrypted with the private key in openssl?
Computing the signature of hello.txt file which has the text hello in it, here is done in two steps:
...
0
votes
0
answers
19
views
Metrics for difference/error of output and ideally output
I'm working in some homomorphic encryption for my Ph.D. but I'm not of the field... So I'm possible going to ask a really simple question that I'm struggling to find an answer on the internet.
...
- 21
5
votes
11
answers
9k
views
For Symmetric Cryptography, why is it considered more important to safeguard a key than the function/algorithm for encrypting/decrypting a message?
As stated for the question above here's an analogy:
You are a robber looking for a house to rob with two different scenarios that might occur.
1. You have a key that you know belongs to a house and ...
- 67
1
vote
1
answer
113
views
A semantically secure encryption scheme can not preserve the length of an encrypted plaintext
A semantically secure encryption scheme can not preserve the length of an encrypted plaintext.
How to prove this? or are there some methods that can be used to obtain such information from a semantic ...
- 85
2
votes
2
answers
114
views
Hard to guess ciphertext
Is there an encryption scheme where it's hard to guess a valid ciphertext without knowing the key and the scheme is CPA secure?
- 31
0
votes
1
answer
79
views
Does sending encrypted hash inside message compromise security
This might sound like a naive question (And maybe it is (It's an early morning Saturday thought, so there might be some clarity of thought missing)).
Suppose we havea protocol that sends messages as ...
- 1
0
votes
0
answers
31
views
Reorderable encryptions [duplicate]
Are there any two encryption function(s) where encryptB(encryptA(data, keyA), keyB) == encryptA(encryptB(data, keyB), keyA).
The two functions may be related or ...
- 897
1
vote
1
answer
68
views
Equality between encrypted hash of data and hash of encrypted data?
Are there any cryptographically strong hash function and encryption function(s) where hash(encryptA(data)) == encryptB(hash(data)). The functions ...
- 897
1
vote
0
answers
58
views
Proving 2-way nesting security
I recently came across the theorem about $n$-way nesting. It states that if $\mathcal{E}=(E, D)$ is semantically secure, then $\mathcal{E}$ is secure for $n$-way nesting. I'm trying to prove the ...
- 11
2
votes
2
answers
502
views
Is there still a place for obfuscation (secret algorithms) in encryption?
As far as I know, the Second World War was won on codes that used obfuscation, not open source. These were also used during the cold war. For general use (not large companies with hundreds of ...
- 21
2
votes
2
answers
1k
views
What is meant by software and hardware implementations of cryptograpic schemes? How to do it?
I have read many cryptographic papers or articles where I have came across about the software and hardware implementation for the cryptographic algorithms. I want to know how its been done. Is there ...
- 21
0
votes
0
answers
30
views
Decryption only on a specified future date?
Are there any encryption protocols or services that are time based. I.e I can encrypt something now and it can only be decrypted on or after 01/01/2100. Like a digital time capsule.
The only way I can ...
- 101
0
votes
0
answers
40
views
Java AES T-Tables Implementation
I am trying to implement an encryption function that uses the AES T-Tables implementation.
I am quite sure that my roundKeys are correct.
I also know that the initial round key addition in the ...
2
votes
1
answer
94
views
Would encrypting several layers of a filesystem be a waste?
I've been thinking about ways to improve the security of my data stored and backed up using the "3-2-1" method.
Moreover by using several layers of encryption to encrypt and decrypt a ...
- 21
1
vote
3
answers
72
views
Zero-Knowledge Proof of Encryption with a Specific Key
Short version:
Given a hash of a plaintext, a public key, and a ciphertext (but not knowing the original plaintext), is there any way to verify that the ciphertext is the plaintext after being ...
- 111
1
vote
0
answers
50
views
Is the SNI extension signed in TLS 1.3?
In TLS 1.3, and since the server signs the entire handshake messages including the server hello message, in this case, is the SNI extension of the client hello message, is it included in the content ...
- 33
0
votes
0
answers
61
views
Sagemath help: Introduction to Lattices
Hi im doing a problem from the Chapter Lightweight Introduction to Lattices in "Learning and Experiencing Cryptography with CrypTool and SageMath"
I'm curious if my implementation is wrong ...
- 1
0
votes
1
answer
61
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