Questions tagged [crc32]
A cyclic redundancy check (CRC) is an error-detecting code designed to detect accidental changes to raw computer data, and is commonly used in digital networks. (wiki) A CRC32 algorithm typically takes in a file stream or character array and calculates an unsigned long codeword from the input. One can transmit this codeword and re-calculate it on the receiver end, then compare it to the transmitted one to detect an error.
crc32
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Can a CRC32 calculation be derived in terms of CRC16 calculations?
I need to calculate a 32-bit CRC but the microprocessor I am using only has a 16-bit CRC peripheral. Would it be possible to still use this 16-bit peripheral as part of my 32-bit calculations, and ...
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Library to do crc32c hashing in React Native/Expo-go for GCS data integrity check?
I am sending some data from my react native app to store it on GCS bucket using signed url.
However, I don't want to risk writing my own implementation for crc32c hashing and making mistake. Is there ...
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What is 'magic number' (0xdebb20e3) in pkzip's APPNOTE?
In section 4.4.7 (CRC-32) of APPNOTE.txt you can find
The 'magic number' for the CRC is 0xdebb20e3.
However, the regular polynomial (0x04C11DB7) of CRC-32 works fine. Bit-reflected, it is 0xEDB88320....
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How to get the same CRC32 like cksum?
I took the source code of cksum and copied the polynomial. This gives the same as the predefined IEEE variant defined in the Go standard library.
package main
import (
"fmt"
"...
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how to decrypt stream based zipcrypto with password?
This is my test of Zipcrypto decryption with known password, It's my own exercise on what i have learned so far , but the code produces bytes different from expected plaintext and i can't figure out ...
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What's the magic number 0xa282ead8 seen in many CRC implementations?
I see the magic number 0xa282ead8 in many CRC implementations, like
https://github.com/kubo/snzip/blob/master/crc32.h
I don't understand CRC calculation very well. What's the effect of this number and ...
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Replicating C# CRC32 generator in JavaScript
I'm trying to convert a specific implementation of a CRC32 generator made in C# into JavaScript for a static website.
It combines two strings into one, converts that into one, generates a CRC out of ...
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what is the purpose of second argument in PKZIP CRC32()?
I am trying to find a way of improving the attack PKZIP encryption but some things aren't clear and for today its this one:
key0 = crc32 ( key0, pt );
This is the CRC32 i know as standard it takes ...
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Why do i get more 256 false positive in PKZIP Decryption key verification?
I have been trying to brute force Key2 of ZipCrypto with first byte of CRC and last byte of encryption header to see how long would it take but i got more than 2000 valid keys.
From the APPNOTE, Key2 ...
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How to get updates from gitlab API if topics changed?
updated_at or last_activity_at don't have any effect on changing a topic. But i really would need to have this info.
Is there a way or do anyone have an idea how i can notice if topics are changed ?
I ...
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CRC32 checksum in Excel
Can anyone help me with my project. I need to create a crc32 checksum in excel. My project is to detect an error if the data of ph value is being edit.
In excel there is to column which is ph value ...
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What is the CRC32 Collision probability of All possible ASCII strings of variable length ranging from 1 to 7
I am trying to find the CRC32 collision probability among all possible ASCII strings of variable length ranging from 1 to 7. Here an ASCII character can range from ASCII 32 to ASCII 126. I tried to ...
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common setup for python crc (6.1.1) and stm32 hardware CRC unit?
I'm sending data from python code to stm32g0xx mcu.
I'm using stm32 hardware CRC computing unit and https://pypi.org/project/crc/ as the other side.
Unfortunately I can't catch the common setup for ...
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Why crc32(0) = 1696784233
why
from zlib import crc32
import numpy as np
x = crc32(np.int64(0))
print(x)
the output is 1696784233, how is this possible since I thought CRC gives the reminder of some generative ...
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Compute POSIX CRC in batches
I have the following C function that computes the POSIX CRC (non reflected CRC, starts with 0, appends length of the data to the data for CRC computation) of an entire buffer.
Reference:
https://pubs....
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