Questions tagged [hashcode]
Hashcode is a result of applying a hash function to data, usually an integer.
105
questions
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 ...
5
votes
2answers
60 views
File duplicate finder
In an attempt to clean out my picture collection I made a script to find all duplicate files
...
3
votes
1answer
66 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
55 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
120 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
88 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:
<...
0
votes
0answers
108 views
Brute-force cracker for hashed passwords
I want to crack the password hash.
This is my data which I want to display the username and the passwords.
This is my code
...
2
votes
0answers
43 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
58 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
147 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
49 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
113 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:
...
2
votes
2answers
66 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'.
...
0
votes
1answer
42 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
195 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
94 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
231 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 ...
0
votes
0answers
76 views
2
votes
1answer
111 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
105 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.
...
4
votes
1answer
34 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
182 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?
...
2
votes
1answer
172 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
1k 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
224 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 ...
11
votes
6answers
5k 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
164 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
350 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 ...
10
votes
1answer
8k 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
1k 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
749 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?
...
5
votes
1answer
3k 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
332 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
842 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 ...
0
votes
1answer
509 views
Using hash_file for image recognition
My team is writing software to be able to grade a basic skills in word/excel/powerpoint test. We are trying to figure out the best way to verify that they included a correct image in their word doc. ...
5
votes
2answers
3k views
Using GetHashCode in Equals
I have a scenario when I want to have a HashSet<ITrackableObjectData>, where ITrackableObjectData has ...
14
votes
1answer
8k views
MD5 implementation in C++11
I'm writing a C++ implementation of the MD5 hashing algorithm based on the pseudocode of this wikipedia article.
...
1
vote
1answer
939 views
encrypt/decrypt person data
Ahead of the General Data Protection Regulation (GDPR) I begin to crypt more than ever before, in fact, all I can crypt become crypt.
However, I wonder if anybody can tell me if this code is secure ...
2
votes
1answer
486 views
Using hashing to create a PRNG with seed
So I wanted to code a simple PRNG for generating terrain in a game. It has to have the following properties:
Computationally cheap
Generate semi random numbers between 0 and an positive integer.
I ...
4
votes
2answers
1k views
Simple hashing and salting algorithm
I have devised what I feel to be a simple hash/salting algo for Java, and am looking for some feedback from people more skilled than myself. Please find below my code;
...
1
vote
1answer
367 views
Implementing feature hashing using guava
I am trying to implement feature hashing in Java. For this I am trying to use Hashing functions from guava.
This is how I am doing it now:
...
3
votes
4answers
186 views
Custom Non-Crypto Hashing Algorithm
Rule of Thumb: Don't roll your own encryption--I'm no cryptographer obviously. Also note my apologies for my awful C-style C++.
For a fun little project I've written my own hash algorithm as a ...
10
votes
2answers
358 views
Python hash format converter
This program should convert a file containing Mana, Hashcat or John the Ripper NTLMv1 hashes to another file containing Hashcat or John the Ripper hashes. Do you have any suggestions on how to make ...
6
votes
1answer
793 views
HKDF Implementation in C#
Based on my prior question about HKDF here https://crypto.stackexchange.com/questions/43933/use-of-pbkdf2-when-no-access-to-hkdf and the responses I received I decided to go ahead an implement HKDF ...
2
votes
2answers
616 views
Leetcode 49: Group Anagrams - Hash function design talk
problem statement
Given an array of strings, group anagrams together.
For example, given: ["eat", "tea", "tan", "ate", "nat", "bat"],
Return:
[
["ate", "eat","tea"],
["nat","...
0
votes
1answer
179 views
Hash Table or map implementation
I'd like to get feedback on whether my hash table is correct or not. Also, any ideas on performance?
...
3
votes
1answer
918 views
Rabin Karp algorithm improvement for string contains A to Z only
I have made some improvement to Rabin Karp algorithm when the source and pattern only contain the characters from A to Z. The improvement is, I use base 26 for hashing (as there are total 26 ...
4
votes
1answer
304 views
Generating Signatures of Tree Structures using an Order-Independent Hash
I'm working with a file format which stores data as a tree. Each node in the tree is known as a Tag, and every tag has a name ...
-1
votes
1answer
274 views
Simple example of a hash table using square as key
I'm studying hash tables, and wrote the following to serve as a simple example.
Does this properly demonstrate the basic concept of a hash table?
The values are ...
