# Tagged Questions

Questions on cryptography and cryptanalysis, encryption and decryption, and the making and breaking of codes and ciphers. Consider posting your question at Cryptography.SE.

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### How to attack universal hash function based on finite-field arithmetic?

As per the Recursive n-gram hashing is pairwise independent, at best paper, I want to use the algorithm described in chapter 6 and 7 (page 7 - 10). The hash works as follows: Define a random ...
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### Cryptarithm - Interesting Math Problem

This is a very interesting cryptarithm that I came across in an old textbook of mine. It is named accordingly as a tribute to the late Bob Marley (singer). Cryptarithm - Tribute to Bob Marley In the ...
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### FSR function of the component-wise product, sum, of two LFSR sequences

Let $T_1$, $T_2$ be two $m$-sequences over $\mathbb{F}_q$ of length $q^n-1$, say $T_1 = (\text{Tr}_{q^n | q}(\alpha^i))_{i \geq 0}$, $T_2 = (\text{Tr}_{q^n | q}(\beta^i))_{i \geq 0}$, for some ...
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### Apply Pohling-Hellman to calculate the discrete logarithm

I am looking at the following example of calculating the discrete logarithm with Pohli-Hellman. The group is $\mathbb{F}_{29}^{\times}$ and we given $y=10$ and $g=3$. We want to find $0 \leq x \leq 28$...
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### What are solid textbooks to learn number theory (for use in cryptography specifically)? [duplicate]

I am an undergraduate looking to have a solid background in number theory before I begin taking courses in modern cryptography. Any recommendations are appreciated!
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### hyperelliptic curve

Please help me to solve this question: Let $H$ be a hyperelliptic curve over $\mathbb{F}_{103}$ given by the equation $y^2 = x^5+1$. let $J$ be the jacobian of $H$ defined over $\mathbb{F}_{103}$. ...
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### Finding the upper bound for a number's factors length

Okay, so the title is a bit misleading but I had to keep it short.. Anyhow, if I have a number X what will the length of it's longest two factors be? For example: $X = 10000$ I want $3$ and $3$ (...
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### Does RSA use two one-way functions?

I'm trying to understand the concepts behind RSA right now. From what I've learned so far, it's pretty much all about a one-way function with a trapdoor: Raising the message to the e'th power modulo N,...