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What is a checksum?

How to verify the checksum of a file and why it’s important

What is a Checksum?

Basically a checksum is hash value as a result of passing a file through an algorithm, either MD5, SHA-1 or SHA-256. Each algorithm produces different results but it’s recommended that SHA-256 should be used to generate the checksum.

# Example format of Kali Linux download page
Filename | Torrent | Version | Size | Checksum Hash

Real word use case

For this example using several commands, a linux distro will be downloaded and its checksum will be validated.

$ wget https://path/to/amd64.iso
$ sha256sum -c amd64.iso
[returned hash]
---------------------------
Checkem v1.0
Written By: bshelling | bshelling@gmail.com
Application validates the integrity of a downloaded file
---------------------------
Enter the original file's checksum:
Enter the name of the file to validate:
[response]

Shelling is what they call me. A forward thinker debugging life's code line by line. Creator, crossfitter, developer, engineer

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