Questions tagged [symmetric]
Symmetric cryptosystems assume two communicating entities share a pre-established secret key.
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How to make a "zero knowledge" cache/key-value store
I'd like to use a possibly insecure cache for storing expensive-to-calculate sensitive information. My requirements are:
If the cache ever gets compromised it should reveal nothing about its ids or ...
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Resistance to integral attacks by North Korean block cipher Jipsam1
The cipher is a modification to AES and is described on this website:
The only difference between Jipsam1 and AES-256 is the S-box. Whereas in AES the S-box is public and constant, namely
$$
\begin{...
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Is it possible to enhance white-box cryptography security by homomorphic encryption?
Background:
Let's discussed based on published symmetric white-box crypto only, such as Chow's white-box AES.
I only know basic concepts/objectives of homomorphic encryption, such as PHE and FHE. ...
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Most simple transport encryption for link-constrained environments
What is the most simple, but yet well-known "protocol" to protect a unidirectional channel over air?
Requirements
The protocol should provide common properties like privacy, integrity and ...
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Why are matrices so common in symmetric encryption?
Matrices have been used in symmetric ciphers since the Hill Cipher (before?) all the way up to modern ciphers such as Twofish and AES.
I understand matrices can be invertible, therefore making them ...
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Safely using ciphers that take small key sizes
Is it feasible to use triple encryption for block ciphers with the maximum keysize being the only significant security issue? I mean $C = E_{k_1}(E_{k_2}(E_{k_3}(P)))$ and $P = D_{k_1}(D_{k_2}(D_{k_3}(...
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Creating an SPN cipher from ChaCha20 or Salsa20's double round function
Given that ChaCha20's building blocks have been also used to construct a hash function, can the double round function from either ChaCha20 or Salsa20 be used to construct a secure SP-network cipher?
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Using machine-learning techniques for data-dependent operations in ciphers
From 'Methods of Symmetric Cryptanalysis' by Dmitry Khovratovich,
The data-dependent operations are one of the most controversial design concepts. We say that an operation is data-dependent, if it ...
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Exchanging key and input in GGM tree?
I am currently working through the exercises in A Graduate Course in Applied Cryptography by Dan Boneh. I am stuck on exercise 4.16 (page 188 in this PDF)
In the GGM tree construction for constructing ...
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Encrypt/Cipher and Decrypt/Decipher a string with a secret
In developing an app I have a simple use case in where I want to encrypt/cipher a string (it could also be a couple of bytes because it's essentially just an IP-Address). On the output I think it ...
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Key Encryption: Does it need to be Authenticated?
Alice wants to store files $m_i$ on Bob's untrusted cloud storage platform, with the additional restriction that she can only store one master key $k$ herself.
She encrypts the files with keys $k_i$ ...
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Key strength comparison: symmetric key vs RSA/DH key
I came across different reputable sources quoting different equivalent symmetric key strengths for RSA/DH keys. This NIST paper (page 67) states the following offer corresponding security strenghts (...
user80928
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Majority encryption algorithm?
Assume that I want to leave an encrypted message to a group of $n$ people in a way that they can only decrypt it if they work together in the following sense:
For some fixed $k < n$ every sub-...
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LR-Oracle Experiment in Lindell and Katz
In reference to the LR-Oracle experiment in “Introduction to Modern Cryptography” (2nd edition) by Lindell & Katz, Definition 3.23 states a scheme $\pi = (Gen,Enc_K,Dec_K)$ is CPA secure for ...
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Design criteria of block ciphers in quantum setting
Some design criteria of block ciphers are already known for the resistance against known attacks like differential, linear , boomerang, etc. Does there already exist any study of design criteria of ...
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