# Tag Info

### determine if 2 byte checksum is CRC-16 based

You could try with CRC Beagle.
Accepted

Found the calculation in a newer version of the J1939 standard than I originally had access to. The manufacturer reused the following equation from SPN 4207: Checksum = (Byte1 + Byte2 + Byte3 + Byte4 ...

### Reverse engineering 16-bit checksum algorithm for 433Mhz RF remote control

I finally figured it out myself. I used the CRC RevEng utility obtained from here: https://reveng.sourceforge.io/ ..to find the algorithm was CRC-16/XMODEM with polynomial 0x1021 and initial value 0. ...
• 71

### Trying to find a checksum (possible CRC?) algorithm for CAN messages on a Porsche

The answer See the code at the end for how to calculate this, but if you're interested, here are the details explaining how I got there. Throughout this text, numbers are mostly in hex, so keep that ...
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### Checksum in CANbus Message

Assuming this is CAN, then there is already a CRC as part of the CAN Spec. Here is a writeup on the CAN CRC. There's some python implementations which build CAN CRCs you could try adapting.
• 878

### Is there a software that can reverse calculate checksums by brute force?

The OA Labs hashdb project has a general framework for this, though it's primarily aimed at strings. Nonetheless, it does have a hefty list of algorithms implemented and an easy way to run them ...

### 2-byte checksum

I do not know what type of CRC-8 this is. I tried everything and I found the solution. Please, see the code below. It works if you do not take 4 first bytes into calculation. Maybe it will help ...
Accepted

### Reverse Engineer an ultrasonic cartridge communication with the station to bypass remaining uses

I think its pretty obvious it is my first time doing this. Example: FB 05 01 03 86 00 8E BF FB: Opens comm 05 01 03: Cartridge model 86 00: The actual number. 86 = a, a = X/150, 00 = b, b = X%150, ...
• 41

### Reverse Engineer 16 Bit error checking byte calculation

So, after reviewing This following Stack Overflow Question I opened up an excel and made some tests and effectively Sum of all bytes is the calculation Hex ff 00 00 04 00 00 00 00 00 13 00 ...
Accepted

### Derive logic for 2 "check bytes" for a USB fingerprint reader

In every line the sum of all big-endian words modulo 0xFFFF equals to 0. Example (the last line): 0x4547 + 0x4953 + 0x0000 + ... + 0x9341 + 0xc0b4 + 0x3b00 = 0x9FFF6 To verify the checksum: append ...
• 185
1 vote

### Bresser Water Leakage sensor checksum algorithm

The checksum has been found! It's a CRC16/xmodem covering the 5 bytes following the CRC. See https://github.com/merbanan/rtl_433/issues/2576#issuecomment-1751134478
• 31
1 vote
Accepted

### Figuring a CRC to edit a PS1 save file

Note: I also posted this answer at the following ROMHacking.net forum post: Re: Figuring a CRC to edit a PS1 save file It looks like the "hash" function is just a simple 32-bit sum: In the ...
• 261
1 vote
Accepted

### Makita XGT battery/charger protocol checksum

Starting A5A5 and trailing FFFF should be excluded. The checksum is just a 16-bit sum of 8-bit bytes. A5A5 0018 501A 4D4C 00CC 120D 0008 0003 0002 1201 120D 0245 FFFF FFFF FFFF FFFF ^ ^ ^ ^ ^ ^...
• 185
1 vote
Accepted

### Mr Cool Remote Control Checksum Algorithm

I found this IR protocol documented in IRremoteESP8266 in the source code files ir_Midea.h and ir_Midea.cpp. The parts of the code I focused on were the struct definition and the calcChecksum function....
• 261
1 vote

### Calculate a 3 byte checksum in configuration file

I found two example line in another file: ...
1 vote

### Reverse-engineering a weird 32-bit possibly not CRC checksum

I still cannot directly comment and this is my only option to respond: here is description of other parameters from same supplier, maybe same model. Some might be transmitted via RF such as battery ...
1 vote

### Is there a software that can reverse calculate checksums by brute force?

There’s this project which has a few more variations beyond CRC: https://github.com/8051Enthusiast/delsum
• 36.6k
1 vote

### Help with working out a checksum

@dieter reichl. Thank you for the suggestion. Another solution that has been found is based on ordering the data LSBF, i.e. 0xDB9800000C11D3 Packet structure is |CS|D0|D1|D2|D3|D4|D5| Checksum ...
• 31
1 vote

### Help with working out a checksum

Ferroli and Lamborghini heat pumps are built by Gree, so why not yours, too? For some IR remote from Gree with 8Byte of data in 2 pulse trains you will find here a description of checksum calculation. ...
1 vote
Accepted

### how to calculate a byte value

solution ,first need to reverse imei array (without F in packet1) and need Addition byte by byte and output need to Addition with 31, thanks
• 31

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