# Questions tagged [algorithm-design]

Design of cryptographic primitives (algorithms), like block ciphers, stream ciphers, random-number generators, hash functions, MACs, key exchanges, public-key encryption or signature schemes. Also tag with the relevant type of primitive. If you ask about a known existing algorithm, also tag with its name.

705 questions
Filter by
Sorted by
Tagged with
96 views

### Why didn't people redesign the key scheduling algorithm of DES to use longer keys instead of using 3-DES?

To overcome short key length of DES, Triple DES was devised. What would go wrong or why didn't people redesign the key scheduling algorithm to use longer keys?
24 views

### Asymmetric non-interactive proof of work scheme

I'm looking for a non-interactive proof of work scheme. I want for it to (1) be faster to find solutions to if you're in the possession of an arbitrary secret, like a private key, and (2) for the ...
72 views

### Scrypt KDF cipher (scrypt CLI) - known vulnerabilities and cryptanalysis?

There is a scrypt cipher that is used for example by some cryptos like LItecoin for their mining algorithm. I never heard of scrypt. I know eg SHA-256 which is well analyzed and considered as secure ...
58 views

### please explain how can i solve it? give me a solotion [closed]

To obtain pseudorandom numbers in the simplest stream cipher, a recurrence relation was used Ri = A×Ri-1 + B mod C During the analysis of the system it was possible to determine the values of A, B, C. ...
40 views

### Division of Point in Elliptic Curve: Getting Back Point

Let $P=(x_p,y_p)$ be a point on elliptic curve $E (a, b) := y^2=x^3+ax+b$, for an integer $n$, there exists a point $Q=(x_q,y_q)=nP$ on $E (a, b)$. If $(x_q,y_q)$ and $n$ are given, what is the ...
62 views

### How to store encrypted solutions of a find location game?

I'm coding a bot on Telegram to sustain a quiz game. A group of people (authors) can upload photos of streets or particular landscapes that they have found on internet, without any description, and ...
51 views

### Are there low-bit hashing or encryption functions for teaching cryptographical concepts?

I understand how hashing and encryption/decryption work at a very high level, where the functions work as a black box. Hashing scrambles the input in a non-uniquely reversible way, whereas encryption ...
178 views

### “One-Wayness” of SHA 1

I recently started learning about Hash Functions for my first time, and I've gone through and have tried to understand the SHA1 process. Brilliant does an excellent job of explaining it step by step. ...
177 views

### Is there a method to encrypt relations in between values of a cyclic value set and generate values out of this set with pseudo RNG? (all at user PC)

Is there a pseudo RNG and function $f$ with 1.) The RNG produces a value $v_0$ out of $N$ different values (set $S$). 2.) Independent of the RNG the function $f$ generates $v_{i+1}=f(v_i)$ ...
75 views

### What is AES subkey? [closed]

I saw the AES algorithm that at the end of algorithm the buffer that stored in the beginning of algorithm the encrypt/decrypt key. now is store the last subkey. What is the last subkey? Why do I ...
57 views

### What does it mean for a number to be “in the order of” a prime number?

In some papers I'm looking at there is some language that says things like "Choose a random number in the order of prime q" and I see some syntax that it is referring to that looks s = Zq (where q is ...
7k views

### Theoretically, what if I were to change some magic numbers in, say, AES?

Purely theoretically. I know it's a bad idea to try to invent your own encryption and that's not the intention here. Just a thought experiment. Say, I change some or all of the magic numbers used in, ...