Questions tagged [hashcode]
Hashcode is a result of applying a hash function to data, usually an integer.
120
questions
0
votes
0answers
64 views
A simple Java integer integer hash set - follow-up 2
(See the previous version.)
Now I have this:
com.github.coderodde.util.IntHashSet:
...
6
votes
4answers
1k views
A simple Java integer hash set
(See the next version.)
The following data structure implements a hash table based set for int values:
...
0
votes
1answer
33 views
Optimizing PowerShell string hasher method
I am building a PowerShell class based tool that works with XML files of as much as a few hundred Kb size, and as many as a hundred of these files. I have extensive validation code that is time ...
2
votes
0answers
125 views
Fnv1a hashing of C# Guid
I have the following implementation of the Fnv1a hashing for a string, which should be correct:
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2
votes
1answer
322 views
constexpr hash function
Here's a constexpr hash function, that will pack a string into the largest unsigned integral type available. So, what do you think?
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2
votes
0answers
36 views
Basic login by username logic with SQL Server
My goal is to make a very simple library with the authentications basics: create a user and save its hashed password, change its password, have a method to check if the password is correct for login.
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6
votes
2answers
93 views
Iter 2: Reusable, robust c++ std::hash<mpz_class> for GMP's big integer type
This is the 2nd iteration of a code review. The 1st iteration (completed) is at
Iter 1: Reusable, robust c++ std::hash<mpz_class> for GMP's big integer type
1. Goal
My intention is to ...
2
votes
1answer
23 views
Checking hierarchical config files for hashed id and informing the user of changes
Our testing suite is configured using a type of hierarchical config file similar to .ini or .toml files. Each 'block' is a test ...
5
votes
1answer
116 views
Iter 1: Reusable, robust c++ std::hash<mpz_class> for GMP's big integer type
This Q&A was iteration 1. Now there is
Iter 2: Reusable, robust c++ std::hash<mpz_class> for GMP's big integer type
1. Goal
My intention is to provide a fast hashing algorithm to hash ...
2
votes
0answers
37 views
SHA-256 implementation in JS (core codes)
As told by experts, I am re-posting the code review request with the code.
Brief Description:
from outside sha256() will be called with parameter having UTF-16 character set.
then after prepareData()...
1
vote
2answers
201 views
HashMap Implementation (dictionary) in Python
I attempted making a hashmap in python, and it was harder, due to some limitations but this is my version of dictionaries in python. Are there any way to simplify or do the same thing in less code ...
4
votes
1answer
187 views
Securely hash passwords
Since hashing algorithms isn't something to mess around with as a beginner. Several howto's explain that one should use already made solutions.
Examples of such pages:
https://crackstation.net/...
9
votes
3answers
2k views
Simple hashing algorithm
TL;DR: The algorithm receives a string as input, allocate another string to be the final digest, and start working on them. For each char on the digest (a null character on a first moment), it XORs it ...
2
votes
1answer
43 views
Custom code for MD5 in js [closed]
I wanted to write my own code for md5 in javascript and learn its inner mechanics. (I know it is not trusted anymore, deprecated, ... but I'm just learning).
I didn't want to just copy the code that ...
3
votes
1answer
87 views
CliwPw - Yet Another Python3 Password Manager
I wrote a (very) simply Python3 password manager to familiarize myself with Sqlite3, and for fun. I am aware that there are already a variety of password managers out there, but I wanted something ...
1
vote
1answer
168 views
InternedString as alternative to regular String
I need to use large strings as a dictionary keys, and I want to optimize the repetitive GetHashCode() and Equals() calls in it.
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8
votes
3answers
2k views
Tiny URL creator
Coding challenge:
Convert a given long URL into a Tiny URL. The length of this Tiny URL
should be fixed and the same for all URLs. You should return the full
URL if given a shortened URL.
I am ...
6
votes
3answers
135 views
File duplicate finder
In an attempt to clean out my picture collection I made a script to find all duplicate files
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3
votes
1answer
91 views
Hashing array of strings as Merkle tree in one function
I want to hash an array of strings into one hash as shown on scheme on the image below. But I do not want to implement some class based Merkle tree. It's just a simple function. Is this a good ...
6
votes
1answer
149 views
Irreversibly hash email addresses while preserving format/entropy
I'm looking to irreversibly hash valid email addresses which have been parsed from mail log data as part of a machine learning project. I need to ensure that the processed data has been scrubbed of ...
7
votes
2answers
451 views
Finding collisions of the first few bits of a SHA-1 hash
My objective is to find a hash collision of my modified hash function. Assuming my modified hash only outputs the first 36 bits of SHA-1. As we know, SHA-1 is a 160-bit hash value, hence, we only need ...
4
votes
2answers
254 views
F# wrapper to generate SHA256 signature for a file
I've created the following module to allow me to generate a SHA256 signature for a file. (In real life this is used to verify an image file hasn't been amended). The cut down code looks like this:
<...
2
votes
0answers
52 views
Database code for Python-based URL shortener
I had implemented a URL shortener with Python and a database. Please review the database part of the code. The idea is to create an MD5 hash of the URL in question and then store it in a database. The ...
3
votes
0answers
259 views
Locality Sensitive Hash (similar to k-Nearest Neighbor), in Python+Numpy
I've tried implementing Locality Sensitive Hash, the algorithm that helps recommendation engines, and powers apps like Shazzam that can identify songs you heard at restaurants.
LSH is supposed to run ...
3
votes
3answers
152 views
Find MD5-hash whose hexadecimals starts like digits of π
I saw a programming puzzle. Find a string containing letters from a to z such that its MD5-hash starts like 314159265359. I am a junior programmer so I would like to know if I can solve the problem ...
2
votes
1answer
64 views
Password generator + storage console app
This is my code to generate and store password localy hashed in txt file.
I would like to kindly ask you whether you could review my code. Btw it is coded as console app. I am currently working on ...
1
vote
1answer
133 views
Hashing interview puzzle
I've stumbled upon this pretty old article about a hashing interview question, and here it is converted to Swift in a more generic way:
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2
votes
2answers
91 views
Checking hash and passwords with a wordlist, more efficient
I have done a small code in which with a wordlist (out68.lst) I get the passwords from the hashes in the file 'shadow3'.
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0
votes
1answer
44 views
Make password/hash verification algorithm more efficient
I am trying to guess the paswords from the etc/shadow file(it has 43 user/passwords). And I have been given some hits about the passwords:
Length is between 4 and 8 characters
There can be only 2 ...
2
votes
1answer
1k views
SHA-1 and MD5 BruteForce in Python 3.7
I've made a python program that can brute-force both MD5 and SHA1 hashes, and I would like know if I could make the program faster or any way I could improve it.
I'm still a beginner in python and in ...
0
votes
1answer
112 views
HashMap Implemention in Java
I just finished implementing a HashMap in Java, with methods:
add(String key, Integer value)
get(String key)
...
2
votes
1answer
835 views
Using Java to implement a hash table (dictionary) with only arrays
I'm new to hash codes/hash tables, so I'm very unsure of my implementation. I want to create a hash table, but I can only use arrays. Specifically, I want to be able to insert things like a dictionary ...
2
votes
2answers
158 views
2
votes
1answer
180 views
Password encrypting tool
I wrote a tool that takes a domain name and a password, concatenates them, hashes the result with sha512, and returns the result encoded in base64 truncated to 32 characters. The main idea behind this ...
0
votes
1answer
150 views
Hash function in C for sets and associative arrays
I wrote a non-cryptographic hash function in C, which I am hoping might be suitable for use in an implementation of hash sets or hash maps.
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4
votes
1answer
44 views
Small script to verify hash of a downloaded file
You know how whenever you download a file you should really compare the hash of the download to the one provided on the website? This makes absolute sense, but it's a pain to do it letter for letter, ...
4
votes
2answers
220 views
Find duplicate files in Linux
This code finds duplicate files in Linux.
I assume that MD5 hash will return unique hash number.
What can I improve in this code?
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2
votes
1answer
594 views
HMAC algorithm implementation
I wanted to understand the HMAC algorithm. So, I implemented it as a Jupyter Notebook with all intermediate steps being output to console. My objective now is to improve it so it may serve as a ...
5
votes
1answer
2k views
Salted hash generator
I've had a go at creating a small class in C# that can generated salted hashes from text. I would like to know how this could be improved (in terms of code style) and whether or not this code is ...
5
votes
1answer
350 views
Python function to hash a python function
I'm working on a sort of distributed build system. The system allows execution of snippets of scripts as build steps. I need to be able to hash these snippets of code in a way that comments and doc ...
14
votes
6answers
9k views
Calculate fingerprint for an object
I need to store serialized objects in a database and I want to avoid duplicates. In order to be able to tell wheter an object is already stored, I have to compare them somehow. My idea was to ...
4
votes
1answer
186 views
Updating data file records
I learnt to code a long, long time ago.
Concerns
Existing approach is messy and will be hard to maintain. System errors are not trapped and the error messages could be better implemented. Final ...
0
votes
2answers
580 views
C# Hash Code for triangle class [closed]
I have a custom class to handle some triangle calculations that I am doing. For the most part I am happy with it, however, there is one aspect that I don't really trust. That is my implementation of ...
15
votes
1answer
20k views
Self-contained SHA-256 implementation in C
I have been looking for a SHA-256 implementation in C with no dependencies (preferably self-contained in a single C-file) with a permissive license but found none to my liking.
Since the Wikipedia ...
1
vote
1answer
3k views
C++ Hashing Passwords - simple algorithm using rand()
I'm studying algorithm's and got to the point of hashing.I was excited about it and I created a little hashing function which will depend on user input and generate passwords. The passwords had to ...
6
votes
1answer
2k views
Basic one way hash to store a password C#
I am storing a password in a database (school coursework so nothing too complicated but I want to challenge myself), I am using a one way hash function, is this suitable? It works I just feel there ...
-1
votes
1answer
1k views
Reading bytes from file to compute its SHA256 hash
I need to get text hash (sha 256), so I need to convert file to its type representation. Is this a fast way to get a byte representation of a file?
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5
votes
1answer
7k views
Check website for update
I have written a program in Python that checks websites for updates (it checks in anything on the website changes) and notifies the user. The idea is downloading the webpage, stripping HTML tags off ...
1
vote
0answers
422 views
MD5 implementation with SSE2
My implementation of MD5 (hash function) works correctly, though it has terrible performance. As a laboratory work, I must write the algorithm myself and implement the brute force.
full code with ...
5
votes
4answers
1k views
Fast case-insensitive hash-code for specific codes
I'm trying to fix another bottleneck identified with a profiler (dotTrace). This time it's a case insensitive hash-code.
Currently I'm using the ...