Does GPG check file integrity?

Hi,

I was under the impression that GPG checked that a file was not altered.

I see in this video

https://www.youtube.com/watch?v=DVUy-t8QSgY

at about 6:05 what seems to be a file being changed and still getting a "good" result.
How can you tell if this is happening on a received file?

Later it shows another method where the file is changed and GPG gives a "bad" result, how would you know if a downloaded file was being checked for integrity or not with GnuPG/GPG4WIN etc?

Many thanks

P.S. I would be checking downloaded files using Windows 10.

Edited by Edward549, 05 May 2022 - 08:33 AM.

Hello @Edward545

Although many would believe it's "splitting hairs", respectfully, we may wish to differentiate between authenticity and integrity. But, that could be a separate discussion.

Only if the unknown file in question has an associated armored ASCII file (.asc file) then an authentication check could optionally be undertaken. Otherwise, GPG would not be able to verify authenticity.

If the unknown file in question can be associated with some kind of a checksum/cryptographic digest/hash, then file integrity could be undertaken. Think VirusTotal.com or a SHA-256 (or equivalent) comparison.

Yet that's another subject for another discussion is digitally signed/countersigned files and think x.509 certificates, etc.

HTH

Edited by 1PW, 05 May 2022 - 09:39 AM.

1PW, Thank you for your fast answer and helpful information. I feel that added clarity to what GPG can do.