Stack Overflow
Stack Overflow

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.

1882 questions
0
votes
1 answer

Verhoeff Checksum function for PostgresSQL

I've found a Verhoeff Checksum function for PostgresSQL at: https://github.com/HIISORG/SNOMED-CT-PostgreSQL/blob/master/Verhoeff.sql CREATE OR REPLACE FUNCTION verhoeff_generate ( input numeric = NULL::numeric ) RETURNS smallint AS $$ DECLARE _c…
Nikk
  • 7,384
  • 8
  • 44
  • 90
0
votes
0 answers

For Loop running infinite C

I am making a checksum error verifying program using C language but I have encountered an infinite loop while executing the program and I don't have any clue why I am getting this. So what I have done in this program is that I am going to first…
Parth Bissa
  • 11
  • 2
0
votes
1 answer

What is the most "bit-efficient" error detection method?

To detect a number of n_errors errors in a code of n_total bits length, we must sacrifice a certain number n_check of the bits for some sort of checksum. My question is: What is the method, where I have to sacrifice the least number of bits n_check…
Nos
  • 215
  • 2
  • 9
0
votes
0 answers

Checksum. Check if the word didn't get distored

I have the following 8-bit word with the checksum added (checksum is the last one) 1 1 0 1 1 1 0 1 **1** I need to check if the word got distorted. I've checked the crc algorithm on wikipedia and I saw that I need a divisor to divide the word with…
Terminat
  • 1,199
  • 5
  • 21
0
votes
3 answers

Calculating a Hash for Entire Optical Media Disc using PowerShell

I'm trying to find a way to create a checksum/hash of CD or DVD using PowerShell. I know Get-Filehash works very well on files, but I can't figure out how to do it for optical media. I was thinking I might be able to use Get-Content to get the…
Nathan
  • 766
  • 2
  • 9
  • 19
0
votes
1 answer

How to avoid buiding a new wheel if nothing has changed

I am building wheels for a pure Python project. The project needs to run in a Docker container, which goes through some heavy build processes after copying the wheel into it. I would like to take advantage of the Docker build cache, but in order to…
kojiro
  • 74,557
  • 19
  • 143
  • 201
0
votes
1 answer

Does a RFID Tag ID (TID) have a CRC?

I was looking at the GS1 Tag Data Standard and noticed the EPC has a CRC-16. However, the unique tag ID (TID), specified in Section 16, does not. Is that the case there is no checksum on the Tag ID? If so, what is the suggested method to ensure the…
Tom
  • 554
  • 5
  • 22
0
votes
1 answer

Is there any solution to compare the two hdfs cluster's result of one table with the same sql

for some reason ,we do a move from the old cluster to the new one .But our new cluster doesnot work well at first ,so we find some problems and fix it . But in the time that I spend on fixing , some etl works ,and sqls may produce some wrong data…
bulbcat
  • 13
  • 2
0
votes
1 answer

DPDK TX checksum offload for TCP has fixed offset from correct checksum

I try to compute checksum for IP and TCP via DPDK checksum offload. The code does the following: ipv4_hdr->hdr_checksum = 0; mb->l2_len = eth_hdr_len; mb->l3_len = ipv4_hdr_len; mb->ol_flags = PKT_TX_IPV4 | PKT_TX_IP_CKSUM |…
HypoGump
  • 51
  • 1
  • 10
0
votes
1 answer

Calculating a 8-bit internet checksum

How would I compute the 8-bit internet checksum of this data? From what I've found so far, to compute the checksum you would add the sums of each of the data parts and then use the 1st compliment on this result sum. But when I try this I…
NewDev90
  • 379
  • 2
  • 21
0
votes
1 answer

Runtime memory (EXE, DLL) corruption

I have app (compiled in delphi) which checks checksum of in memory loaded modules which this program uses (dlls and exe). I am checking for code (text) section and relocation table section of dlls and exe. Sometimes over time I got different…
Giraffe Lion
  • 1,641
  • 1
  • 11
  • 6
0
votes
0 answers

Checksum in MySQL different

Is there any reason why identical tables in MySQL 5.0 might have different checksums, and if so, is there any way to fix this? I have two replicated databases that inexplicably have a different checksum. The first time this happened it disappeared…
Matt
  • 1,928
  • 24
  • 44
0
votes
1 answer

Finding the CRC / Checksum in a control unit message

I have a list of messages from a control unit that i'm trying to replicate. I have the body of the message correct, however, i can't seem to work out what CRC or checksum is being utilised. 00 FE 0F 32 A8 80 84 90 00 FE 0F 32 A8 80 84 54 00 FE FF 31…
RNtech
  • 1
  • 2
0
votes
1 answer

Find used CRC-16 algorithm

I'm struggling to reverse engineer a section of data associated with a CRC-16 checksum. I know the polynom used to calculate the original checksums is 0x8408 but nothing else, I don't know initial value (if any), final XOR value (if any), if the…
Spacebrain
  • 87
  • 12
0
votes
0 answers

Incorrect and variable IP packet checksum value

GOAL: crafting a packet from zero and send it. PROBLEM: after I enabled "validate checksum" on wireshark I noticed that the expected checksum value should be 0xa85d but the checksum function I'm using computes a different value each time. Why the…
Maicake
  • 1,046
  • 10
  • 34
1 2 3
…
99 100