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Questions tagged [checksum]

A checksum or hash sum is a fixed-size datum computed from an arbitrary block of digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage. The integrity of the data can be checked at any later time by recomputing the checksum and comparing it with the stored one.

A checksum or hash sum is a fixed-size datum computed from an arbitrary block of digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage.

The integrity of the data can be checked at any later time by recomputing the checksum and comparing it with the stored one. This process doesn't guarentee the data hasn't been corrupted, but is a good indication.

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Tcp checksum oF Retransmission packet SDN network (openflow protocol)

I have created a SDN network in the mininet and i started to push a tcp flow between 2 hosts by using iperf command . I use wireshark for some analysis. I found that when the packet is retransmitted for any reason, the checksum of the…
Abdelhay Gamal
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Check code from byte array

For my bluetooth communication I need a check code / checksum from a byte array. The bluetooth communication protocol says: "The instruction of check code: check code=(0 - expect the sum of byte in whole byte)" I already got a working method in…
Patricks
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Can anyone advise how I can get the TCP / IP packet checksums verified?

I have a packet that I have manually created for a SYN/ACK but I get no reply from the server. This is all wireless/GSM stuff so I cannot use a sniffer. I have calculated the TCP and the IP header checksums manually a few times and they seem…
berntd
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Checksum computation: Reading file while writing

I'm trying to compute checksum of a transferred file. Traditional way is to receive and write the file to disk and then read again from disk and compute checksum. Alternatively, I can write and read simultaneously to optimize the process. I observed…
earslan
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Tcl - Creating a Sha256sum of a Tar.gz file

Having difficulty getting this code to work: I have a list of files I want to archive as a tar.gz file and then create a checksum of the files set chan [open myfile.tar.gz w] zlib push gzip $chan tar::create $chan file1.txt file2.txt file3.txt…
Nicholas Tree
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Directory checksum

I have directory with 80 files, I want to check the checksum of the directory. I want to verify that the content of the directory is match to the latest version. I working with real time system so It need to be efficient. I found some file checksum…
LIOR
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Two the same files, different size

I have been playing with the files' sizes a bit as I use CheckSum to prevent from creating duplicates of the same file. CheckSum works absolutely fine, exactly as I would expect it to work. The problem I face is a fact that the same files have…
Szymon
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Config File Checksum guessing (CRC)

I'm currently "hacking" an old 3d Printer, built in 1996. There is Software running on an old Windows PC. I need to modify some parameters which are not accessible from the front end, so I wanted to modify the config files. But if I modify…
Alex
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Checksum Python

I tried to make a checksum function but my tests returned None instead of the expected output. Can you point out where I went wrong and how to correct it? I am trying to get a numerical sum out of a bunch of strings in the test code. def…
Matthew Miller
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What is the fastest method to compare two large files in Java

Currently we have a nightly automation run that does a comparison between a resulting test file produced by our software and a baseline file. This comparison is is done several times and the files are large. The file comparison is the bottle neck…
Huckleberry
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Checksum for HEX string Python

Here is HEX string: 57 F1 0F 9A A8 B7 00 08 0B 19 10 00 00 00 00 00 11 0B 15 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 A8 and B7 is a checksum that i need to calculate In C it calculated like that (100% worked): void…
Павел Кузиков
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Recognising hash/checksum

Hello everyone, In one of projects I've found that data encrypts with algorithm I have never meet before. It converts input string to 10-symbol numeric string. It's definitely not one of popular hashes (md5, sha1, etc) or check sums (crc16, crc32,…
mbte
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why is Sqlite checksum not same after reversing edits?

obviously editing any column value will change the checksum. but saving the original value back will not return the file to the original checksum. I ran VACUUM before and after so it isn't due to buffer size. I don't have any indexes referencing the…
Bengineer
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React renders different values on client and server leading to checksum mismatch

I am very new to react.Problem statement :The selected value is picked from json respose from the backend.The subscription with selected =true in json must remain selected on intial load and across navigations on the screen irrespective of…
Prabhu
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How can I check file integrity after the file is converted?

I am new in data integrity check. I have an application which handles retrieving PDF data from database and save locally. Afterwards, the app need convert the PDF file into PNG pages and upload the PNG pages as stream up to Cloud. My question is if…
Hao Zhou
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