SHA256: Secure Hash Algorithm

[last updated: 2022-10-10]
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• In order to guarantee that files you download from the web are valid, without errors or tampering,
  there are cryptographic algorithms that can be applied to the file by the authors, that create a hash value that uniquely identifies the totality of the file.

  The hash value or "digest" is a multi-character string (perhaps 50-75 characters) that is published and distributed by the program authors along with the program/file that you want to validate.

• SHA256 is a popular algorithm used for a lot of Linux programs.
  The SHA256 hash value will typically be published in a text file, named something like: [filename]-SHA256.txt
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• Verify downloaded file:
  $ sha256sum [file or program name]

• The sha256sum command is bundled with the Linux OS.
  When it's executed as above, it generates a hash value for the downloaded file.
  You can manually compare the generated hash value with that in the ...SHA256.txt file.
  If the generated hash matches the one published in the text file from the program authors,
  then the downloaded file is validated.

• Verify integrity/authenticity of the downloaded hash file:
  ... using ...txt.gpg ...

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