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Questions tagged [crc]

Cyclic redundancy check. An error checking mechanism used for verifying data integrity in serial protocols.

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Negative of UInt8

I have this code in Objective-C and I want to write it in Java. However there is the statement (-(crc & 1)) that gives me problems. After some googeling it seems that the negative of an unsigned is generally not well defined. I didn't quite…
findusl
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How do you compute the XOR Remainder used in CRC in java?

there's a similar question [question]: How do you compute the XOR Remainder used in CRC?. I know the method which is explained in the above question. the problem is how do I implement it in java.
yogupta
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CRC16-CCITT for binary file using python

What is the maximum size of file that CRC16-CCITT calculates? If I split the binary file on blocks of 256*1024, can I add the crc result of each block to determine the CRC of the whole file? what is the criterias to choose CRC-16CCITT and…
Stack Over
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reverse engineering a checksum algorithm

I am all the time trying to determine how to reverse engineer this checksum. It should be a simple one, it is just a checksum for a firmware version of a device. Here are 5…
user16556
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What does mask variable do in this CRC checksum calculation?

The question is about code in figure 14-6 in here. The mask is calculated as: mask = -(crc & 1) Why do we & crc with 1 and then make result negative? The Figure 14-5 does not have this mask variable, why? Edit: So since this point is clear, why do…
quantum231
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Serial Communication Between Arduino and EPOS: CRC Calculation Problems

I am trying to interface with an EPOS2 motor controller over RS232 Serial with an Arduino Duemilanove (because it's what I had lying around). I got it to work for the most part - I can send and recieve data when I manually calculate the CRC checksum…
Rachael Putnam
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Create a PNG image that has the same XMODEM-CRC as an exiting PNG image

I have a problem which requires me to create a brand new PNG image, that has a same XMODEM-CRC checksum as an existing PNG image. The new image must have a PNG structure and the exising image's XMODEM-CRC is: 0xC553 I am looking for a way which i…
iYehuda
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Cyclic Redundancy Check How To?

First off, I'm not sure if this is even the right place for it but I could really use any help. So I am given an ASCII file that contains the string abcdefghijklmnopqrstuvwxyz12345-ABCDEFGHIJKLMNOPQRSTUVWXYZ12345aand I am supposed to run a CRC-15…
Yitzak Hernandez
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I need CRC Reverse Code for my CRC64 Checksum Coding

Can someone please code me the CRC64 Reverse Algorithm in C#? I am unable to code it, can't understand anything. Thanks, I have copied the CRC64 Checksum code from C++ and converted it into C# .NET. The entire code is displayed below: using…
Tush
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Convert this CRC32 algorithm to Python 3.3

I need to convert this CRC32 algorithm to python (using 3.3), but I am a python noob. I tried the built in binascii.crc32(), but the CRC was incorrect. Apparently, STMicro does the CRC32 a bit different. I found an algorithm that works, now I just…
eyesonly760
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Reverse engineer checksum/CRC for RF packets

Good day to all hackers. I've been trying to figure out a checksum algorithm for RF transmissions, but after many hours, still no luck. The device I'm trying to "hack" is "Milux RF thermostat", branded as LHZ Lucht, manufactured by Watts... it…
user1599438
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Arduino CRC32 Code Explanation searched

I've started with Arduino and the next task I set to myself is to unterstand how a CRC check could be implemented. I think I've found a decent code for that. But simply implementing...no, I want to learn. I searched a bit on CRC in general and I…
mathnow
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CRC algorithm resulting into values of less than 16 bit

For a human-friendly "checksum" value I like to generate values in the range of 0 to 99 only. The input is a string of ASCII chars (mainly a-z and 0-9). I figure I should use some kind of CRC algorithm for this, but I wonder how I get the best…
Thomas Tempelmann
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Programming the CRC algorithm manipulating Strings in Java

I'm a university student currently programming an assignment. I need to program various methods for sending and receiving messages, like for example the Hamming algorithm and Cyclic Redundancy Check. I'm trying to program the CRC method on the…
Ignacio Concha
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CRC fail when extracting sample Unity project

How do I properly extract the zip files located at https://parse.com/downloads/windows/ParseUnityStarterProject-CSharp/latest and https://parse.com/downloads/windows/Parse/latest I have tried the built in Windows zip functionality and 7zip run with…
John Smith
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