Questions tagged [hashing]
Challenges that involve summarizing a large amount of data in a single, much smaller number.
26
questions
27
votes
30answers
3k views
Output with the same length always
With challenges like Output with the same length as the code and Create output twice the length of the code, I thought of a separate, but similar challenge.
The task is to produce an output. It can ...
1
vote
4answers
288 views
Nearest hamming cycle period in MD5
This riddle was inspired by that thread. Consider that you are super-hacker and try to break MD5 hashing algorithm by looking for a hash collisions for a given hash string which your friend gave to ...
15
votes
8answers
2k views
Rotation invariant fingerprinting
Imagine we have some polyomino and would like to uniquely identify them, however the polyominos can be rotated, so blindly hashing them won't give us the same fingerprint for a piece and a rotation ...
16
votes
14answers
1k views
Arbitrary Length Hashing
Consider you have a hash function \$\mathcal{H}\$ which takes strings of length \$2n\$ and returns strings of length \$n\$ and has the nice property that it is collision resistant, i.e. it is hard to ...
13
votes
15answers
2k views
Logic Gates Manually
Make a program that simulates the basic logic gates.
Input: An all-caps word followed by 2 1 digit binary numbers, separated by spaces, such as OR 1 0. The gates <...
34
votes
18answers
4k views
26 Singers, 26 Letters
According to RollingStone, below are the 26 greatest singers of all time:
...
-5
votes
1answer
424 views
Implement the MD5 algorithm! [closed]
Your challenge is to output the MD5 hash of your input. The specification of MD5 can be found here. Crypto builtins are NOT allowed. Shortest code wins. Psuedocode:
...
11
votes
9answers
1k views
What characters are more common in my MD2 hash?
The challenge is simple
Write a script that, when given a string input, will hash the string using the MD2 hashing algorithm, and then return either a positive integer or negative integer output ...
19
votes
3answers
720 views
Meta radiation hardener
Background
On this site, we occasionally have questions requiring programs to be "radiation hardened"; this means that the program has to be able to survive the deletion of one or more bytes, no ...
7
votes
3answers
544 views
Geohash Generator
XKCD Comic:
Goal:
Given a date, the current Dow Opening, and your current coordinates as a rounded integer, produce a "geohash."
Input:
Input through any reasonable means (STDIN, function argument,...
35
votes
9answers
2k views
Help me recognise my monster
Background
The computer game NetHack dates from 1987, before the use of graphics in computer games was widely established. There are lots of monsters in the game, and potentially a lot need to fit on ...
18
votes
4answers
1k views
Implement SHA-256
Given a sequence of bytes, output the SHA-256 hash value of the sequence.
The SHA-256 Algorithm
The following pseudocode is taken from the Wikipedia page for SHA-2.
...
14
votes
9answers
1k views
Compute CRC32 Hash
Credits
This challenge originated from @miles.
Create a function that computes the CRC32 hash of an input string. The input will be an ASCII string of any length. The output will be the CRC32 hash ...
73
votes
24answers
4k views
Tweetable hash function challenge
In this code-challenge you will write a hash function in 140 bytes1 or less of source code. The hash function must take an ASCII string as input, and return a 24-bit unsigned integer ([0, 224-1]) as ...
17
votes
5answers
3k views
Mine for 2016 in Bitcoins! PCG.SE New Year's Puzzle 2016
In the Bitcoin protocol, 2016 is a very special number. The "difficulty" of finding a hash to create a new block is adjusted every 2,016 blocks to approximate changing once every two weeks.
This ...
2
votes
0answers
671 views
Make a program that outputs its own MD5 hash [duplicate]
Challenge: make a program that outputs a MD5 hash of its source code.
You should not use tricks that would be considered cheating in a quine sense (discussed here).
Using built-in functions and ...
12
votes
20answers
3k views
Cryptographic hash golf (robbers)
This contest is over.
There are no remaining crackable answer in the cops challenge.
Companion thread of Cryptographic hash golf
As a reminder, here are the rules for robbers from the main ...
34
votes
23answers
4k views
Cryptographic hash golf
This contest is over.
Due to the nature of cops-and-robbers challenges, the cops challenge becomes a lot easier when the interest in the associated robbers challenge has diminished. Therefore, ...
10
votes
6answers
447 views
Implement a Variable Length Hash
My friend and I have this game that we play with words. It is a fun pastime and it involves "canceling out" letters in a word until there is nothing left. I am really tired of him being so much faster ...
6
votes
6answers
2k views
Decode MD5, Brute Force
The Challenge
Create a program that brute-force* decodes the MD5-hashed string, given here:
92a7c9116fa52eb83cf4c2919599c24a which translates to ...
7
votes
4answers
4k views
Un-hash the Java Hash
Hash Un-hashing
The basic goal of this challenge is to exploit the high probability of collision in the Java Hash function to create a list of plausible inputs that created an outputted hash. The ...
-1
votes
3answers
660 views
Hide your hash function
So you are tasked with creating an open source password authentication system but you want to reveal as little about the implementation of the hash function as possible. Can you write a function that ...
63
votes
20answers
8k views
Hash collision: “NO” means “YES”
This Code Golf was inspired by the recent Daily WTF article You Can't Handle the True!, which features a string comparison written as:
...
7
votes
10answers
1k views
Write a hash function for Morse Code [closed]
Your goal is to write a hash function, that accepts morse code character and returns a hash code that you get to define.
You can be sure, passed string will be:
One of the Latin characters (A-Z) ...
13
votes
7answers
2k views
Morse code to standard output
This question involves taking input in Morse code as . (period) and - (minus symbol), with spaces to separate the input. Your task is to convert the code to standard output. You can assume that the ...
15
votes
5answers
993 views
Implementing the SHA-1 hash algorithm
The goal of this code-golf is to create a program that takes a string as input, and you have to output the SHA-1 hash value as a hexadecimal number. You can find the pseudocode for SHA-1 here
Other ...
