Questions tagged [crc]

Cyclic redundancy check (CRC) is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to raw data.

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141 views

figure out the CRC bytes [closed]

I am trying to write some code to figure out a CRC on the following byte sequence for an AI algorithm class project, and would like to seek some suggestions from this forum. For example, the ...
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1answer
234 views

Trying to figure out the CRC or checksum for a Fluke 233 wireless display multimeter

Downloaded and compiled CRC_reveng, but it's not finding any solutions. Maybe I'm over-thinking this? Not knowing too many other tricks that might be performed on the data or CRC before or after it's ...
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271 views

Puzzling 16bit checksum/CRC reverse engineering problem

We're having a hard time figuring out how the checksum/CRC is calculated for this serial communication protocol we're required to reverse engineer. This is a communication protocol used back in the ...
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0answers
559 views

find CRC algorithm, having some input and output data pairs

I'm trying to discover the algorithm of a lost software, there is an equipment that requiest some data, and validates the data using the "KEY", if you change any parameter of the data then you need a ...
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1answer
283 views

Reversing checksum calculation of embedded communication

I need to find relations last byte with others. Tried these solutions, but it didn't work. My tries: * When I write all datas as binary, 1's count not equal but last byte same for some datas. * When ...
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1answer
673 views

Reverse engineering of some checksum algorithm

I am trying to reverse some communication protocol between transmitter (controlled by PCF7952 chip) and receiver on 433 Mhz frequency I know how to prepare the "right" package which would be received ...
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1answer
1k views

Finding out checksum algorithm

I have old serial communication protocol and having some trouble finding out about checksum algorithm that has been used. I've tried several CRC16 algorithms and none of them seem to work. Tx message ...
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1answer
1k views

Reverse engineer 4-bit CRC in LG IR packet

I am reverse engineering IR protocol of LG air conditioner. AC generally send the whole current state of remote on each key press. Data sent is 28 bits long, last 4 bits seem to be the checksum. I ...
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2answers
2k views

Bypassing CRC check

I am trying to reverse a software which loads its own dll-file filled with protection stuff. I was able to successfuly locate the functions of interest. Then I patched the first function and test the ...
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3answers
1k views

Hash algorithm written in C decompiled with IDA

I have been working on rewriting a program, although it uses a hash to fingerprint the file, I have used IDA to find the function doing the hash and what it is doing to the file before it sends it to ...
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1answer
595 views

Reversing checksum algorithm

I am writing a program to control an old camera over serial. I have no access to the protocol or source code of the demonstration program that i have, but i can generate some correct checksums by ...
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0answers
2k views

Reverse Engineering a 8 bit CRC checksum

I am trying to create a communication interface using C Language to an Air conditioning system, after analyzing the data packets I have identified that the data packet is consist of an 8 bit CRC (I am ...
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2answers
544 views

Single step exception at the beginning of an unrelated function

I'm reversing an application and I know for a fact it employs CRC checks, so if I modify the code, for instance hooking something, it'll be detected. The application uses a DLL which I replaced with ...

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