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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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Copy/move file and calculate checksum (md5) at the same time

I am putting together a program that takes care of moving (large) files from one place to another. These files are usually 1gb + and are incredibly important to us. We are a data acquisition company, so data is literally our product. What I'd like…
Matthew Goulart
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Getting different LRC (Long Range Checksum) result

I'm trying to send a request to a TCP/IP terminal. My LRC function as below: public byte GetLRC(byte[] bArr) { byte LRC = 0x00; foreach (byte b in bArr) { LRC ^= b; } return LRC; } But the…
Ringo
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PMS5003 with ESP8266 - many checksum errors

I have an ESP8266 connected to PMS5003 particulate matter sensor through (hardware) UART. I'm getting many checksum errors while reading from PMS5003. Here's the library that I'm using to communicate with PMS5003: PMS5003.cpp #include…
Defozo
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Checksum error for ubuntu-14.04.5-server-amd64.iso download with Packer

I'm having the following error on the checksum key: virtualbox-iso: Error downloading: checksums didn't match expected: dd54dc8cfc2a655053d19813c2f9aa9f. I've took the key from ubuntu release site. An idea about the correct key to set as reference?
OPMendeavor
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How can I get the correct modulo value from an signed int in php?

When I do a crc32 call on a 32 bit PHP system (PHP_INT_SIZE is 4), the resulting integer value can be negative. How can I get the correct modulo value from the number, regardless if I am on a 32 or 64 bit system? function checksumChar($str) { …
chiborg
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Protocol checksum reverse engineering

I'm trying to reverse engineer a protocol's checksum. It seems to be a 4-bit nibble-based protocol. The following is a binary representation of a packet in the protocol: 1000 0001 1000 0001 0000 0001 1111 0010 1010 : 1001 1000 0001 1000 0001 0000…
nohupper
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Xcode build phase

Hey, I'm implementing MD5 checksum on my app(for preventing binary crack). I created a command line tool that will generate the hash for the binary and will add it to the .app folder. However, I didn't figure out how to add it as a build phase. I've…
Udinesio
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checksum accepted result

I am calculating checksum in a stored procedure : CHECKSUM_AGG(checksum(cid,tableid, sid, pid, vid, Tablename, ColumnKey, ColumnValue)) from #FDATA But when @FDATA has these data: 1052 2 100 100008 VIS0 form.PAN_ELIG 4401001 1 1052 2 …
aggicd
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CHECKSUM_AGG(checksum()) returns stars (**********)

I am calling id int , tableid int, seid int, ptid int, VISID NVARCHAR(50), Tname AS SYSNAME , ColumnValue NVARCHAR(50), ColumnKey NVARCHAR(50), @HashValue NVARCHAR(50) OUTPUT select @HashValue = CHECKSUM_AGG(checksum(id,tableid, seid, ptid, VISID,…
aggicd
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How to get the number generated by CHECKSUM from a mysql table?

MySql: When I execute CHECKSUM TABLE tablaa gives the result: Table | Checksum prueba.tablaa | 1290260502 If you notice, generate the number 1290260502, how can I get that number from a query? Thanks
anlijudavid
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Checksum mismatch on update: SVN v1.8.10

I am getting this error while running svn up command: svn: E200014: Checksum mismatch. I tried the solution here: SVN - Checksum mismatch while updating (which involves running command svn update --set-depth empty and svn update --set-depth…
Wamiq
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Should I cache md5 of file or is it fast enough to not need to?

I need to check md5 checksum of ~10-20 files on server every time a user logs in. Each file can be ~10MB. Should I cache md5 of these files or do it in real-time without wasting time & bothering? P. S. there will probably be up to 10k logins a day.
Gintas_
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Shell script file copy checker

I copied and re-sorted nearly 1TB of files on a Drobo using a find . -name \*.%ext% -print0 | xargs -I{} -0 cp -v {} %File%s command. I need to make sure all the files copied correctly. This is what I have so far: #!/bin/sh find . -type f -exec…
VorTechnix
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Does JSch implement SFTP inherently?

This is not a duplicate of How to perform checksums during a SFTP file transfer for data integrity? as I am more looking for the details of JSch and how it implements SFTP. If it implements SFTP, then as pointed out here, there is no need to do file…
N R
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Checksum of unsigned bytes in Java

How to convert this JS code to Java, if bytes in array "response[]" are unsigned? int i; byte crc = 0; for (i = 1; i < 8; i++) crc+=response[i]; crc = 255 - crc; crc++;
Andrey Andreev
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