Questions tagged [hash]

Question 1

I am hashing a bunch of strings made up of a finite number of known keyword strings (n many keyword strings). Here I want to generate a perfect hash s.t. each ...

Question 2

When using the CGen tool to convert the SHA-256 algorithm into Conjunctive Normal Form (CNF), the input and output bits are represented by DMAC literals. However, I am specifically interested in ...

Question 3

Given the consistent hashing ring system, i.e., with $S$ serves, $C$ clients and a random hash function $h$, how can we choose the number of virtual nodes per server $V$, so that the probability that ...

Question 4

For $n$ elements, a two-level hash table contains an $O(n)$ top-level hash table whose entries are hash tables also. Each table samples from a 2-universal family. To hash an element $x$, we first hash ...

Question 5

I want to generate numbers in the range $0 \leq n < 2000$ in a random order. The risk of using "generic random number generator" $\mod 2000$ is that it will cycle sooner in that range, or ...

Question 6

Daniel J Bernstein's "Multiply 33 and add" simple hash is surprisingly hard to find the original reference to. Googling provides descriptions in language implementations such as PHP ...

Question 7

Is there some algorithm that can transform any string input (of any length) into a shortest possible coherent/unique numeric identifiant. By "coherent", I mean that the same input will ...

Question 8

I was learning the Polynomial Hash function in python, the one used in Rabin Karp Algorithm This is the implementation I was taught: ...

Question 9

Lets assume that the load factor of a hash table of size $n$ became inappropriate. The process of re-hashing involves choosing a new hash function. A good choice of a new function will make the cost ...

Question 10

I had a difficult assignment in my Data Structures and Algorithms class. We need to implement a program that computes a function f(n) based on the following known values of n and f(n): n : 9689 ...

Question 11

Suppose I have integers that follows a power distribution: $P(n) \propto 1/(n + 1)^\alpha, n \geq 0$ What hash function is a good choice to avoid collisions. The usecase is keys in an ...

Question 12

Given a cryptographic hash, $ \text{hash}(A || B || C) $, and the last block added to the hash, $ C $, can you determine $ \text{hash}(A || B) $? In other words, can you roll back the last round of a ...

Question 13

I have two 64-bit numbers a and b which have a few properties: only 49 out of the 64 bits are used (15 bits are always 0), and ...

Question 14

Given an array with the size of $n$ of integer numbers. Our goal will be to analyze the expected running time of an algorithm that uses a hash table to find (if exists) a pair $(a,b)$ subject to $2<...

Question 15

Do any streaming hash functions exist that provide the same result if the input is reversed? That is to say, is there some hash function, $h$, such that: $$ h(h(h(h(0, x_1), x_2), ...), x_n) = h(h(h(h(...

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Questions tagged [hash]

Can the constants of FNV1A be computed for a specific set of strings to make it a perfect hash function?

Identifying the DMAC Literals Representing Internal Processes (Message Schedule, T1, T2, etc.) in SHA-256 CNF Conversion Using CGen Tool

How virtual nodes affects consistent hashing ring?

Two-Level (Perfect) Hash Tables in Practice

How to make a pseudorandom generator that has the longest possible period in a range?

Where was DJBX33A first published?

Transform any string into the shortest coherent/unique numeric identifiant

Understanding Polynomial Rolling Hash Function by Modular Arithmetic

How bad re-hashing can cost?

Using XOR operation, a MOD operation compute a function f(n)

Hash function for use with hash table, given power distributed integers

Can you unwind a cryptographic hash function's last round?

A good way to hash two numbers with known properties together

Find a pair $a,b$ with a range condition in Hash table

Reversible streaming hash function

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