error: blackarch: signature from “Levon ‘noptrix’ Kayan (BlackArch Developer) ” is invalid (SOLVED)

When trying to update Arch Linux with BlackArch repositories with the command

sudo pacman -Syu

an error occurred:

error: blackarch: signature from "Levon 'noptrix' Kayan (BlackArch Developer) <noptrix@nullsecurity.net>" is invalid

The error message says that the signature of one of the BlackArch developers is not valid.

Method #1

To solve this error, just delete the /var/lib/pacman/sync/blackarch.db.sig file:

sudo rm /var/lib/pacman/sync/blackarch.db.sig

Then run the update like this:

sudo pacman -Syyu

The error no longer occurs:

I don't know exactly what caused this problem, perhaps a file corruption due to a network problem during a system update.

After updating the information from the package repositories, the /var/lib/pacman/sync/blackarch.db.sig file was recreated and the error no longer occurred. That is, there is no need to worry that your Linux will lose any functionality.

Method #2

If the previous method did not help, then try temporarily changing the mirror to blackarch.org/*. The BlackArch mirror can be set in the file /etc/pacman.d/blackarch-mirrorlist or /etc/pacman.conf. Open this file and put the first line:

Server = https://www.blackarch.org/blackarch/$repo/os/$arch

File is corrupted (invalid or corrupted package (PGP signature))

The error in question may be accompanied by another problem, a message about a damaged file:

:: File /var/cache/pacman/pkg/trufflehog-1:v3.59.0.r10.gf09bce3f-1-x86_64.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n] 

The package manager prompts you to remove this file. If you delete this file without resolving the problem with an invalid signature, which is discussed first, then the newly downloaded file may again be considered damaged.

In case of a message about a damaged file and an incorrect signature, you must follow the steps indicated above. After that, in my case, the message about the damaged file did not disappear automatically, ones need to delete the file and start the update again so that the file can be downloaded again. After this, all errors were resolved and the system was updated.