dnf install gnutar ... bf81de15: NOKEY

I am using dnf configured for *OpenMandriva Cooker*, and I have this problem bf81de15: NOKEY when trying to install gnutar. What is the procedure to do in these cases? And if it is not possible, how to omit the key?

Last metadata expiration check: 0:33:36 ago on Wed Apr  3 17:49:59 2024.
Dependencies resolved.
==================================================================================================================
 Package                  Architecture             Version                  Repository                       Size
==================================================================================================================
Installing:
 gnutar                   x86_64                   1.34-4                   cooker-x86_64                   965 k

Transaction Summary
==================================================================================================================
Install  1 Package

Total size: 965 k
Installed size: 3.1 M
Is this ok [y/N]: y
Downloading Packages:
[SKIPPED] gnutar-1.34-4-omv2390.x86_64.rpm: Already downloaded                                                   
Running transaction check
Transaction check succeeded.
Running transaction test
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by executing 'dnf clean packages'.
Error: Transaction test error:
  package gnutar-1.34-4.x86_64 does not verify: Header V4 RSA/SHA256 Signature, key ID bf81de15: NOKEY