[sane-devel] SANE public key is not available: (pj.world@gmx.com)

[pj . world]

Hi, I am using LinuxMint20 and trying to update to the latest SANE by using "sane-project team" link: https://launchpad.net/~sane-project/+archive/ubuntu/sane-release

 

First command in terminal: sudo add-apt-repository ppa:sane-project/sane-release

 

You are about to add the following PPA:
 Ubuntu SANE packages from SANE Stable Source (https://gitlab.com/sane-project/backends/-/releases).

Please send scanner related questions to the SANE mailing list:
sane-devel at alioth-lists dot debian dot net.

If you need the more recent scanner driver from git, you can use my other PPA: https://launchpad.net/~sane-project/+archive/ubuntu/sane-git.
 More info: https://launchpad.net/~sane-project/+archive/ubuntu/sane-release
Press Enter to continue or Ctrl+C to cancel

Executing: /tmp/apt-key-gpghome.4XgmtlN5t8/gpg.1.sh --keyserver hkps://keyserver.ubuntu.com:443 --recv-keys B5904B171A07B33815710C02DDEAC554C101175B
gpg: key DDEAC554C101175B: public key "Launchpad PPA for sane-project" imported
gpg: Total number processed: 1
gpg:               imported: 1
gpg: invalid key resource URL '/etc/apt/trusted.gpg.d/home:pzz.gpg'
gpg: keyblock resource '(null)': General error
gpg: key 23E07629B9E3C9E4: 1 signature not checked due to a missing key
gpg: key A6616109451BBBF2: 12 signatures not checked due to missing keys
gpg: key 3B4FE6ACC0B21F32: 3 signatures not checked due to missing keys
gpg: key D94AA3F0EFE21092: 3 signatures not checked due to missing keys
gpg: key C8CAB6595FDFF622: 2 signatures not checked due to missing keys
gpg: key 871920D1991BC93C: 1 signature not checked due to a missing key
gpg: Total number processed: 8
gpg:       skipped new keys: 8

 

Second command in terminal: sudo apt update

 

Get:12 http://ppa.launchpad.net/sane-project/sane-release/ubuntu focal InRelease [18.0 kB]
Err:9 http://ppa.launchpad.net/sane-project/sane-git/ubuntu focal InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY DDEAC554C101175B
Err:12 http://ppa.launchpad.net/sane-project/sane-release/ubuntu focal InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY DDEAC554C101175B
Reading package lists... Done
W: GPG error: http://ppa.launchpad.net/sane-project/sane-git/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY DDEAC554C101175B
E: The repository 'http://ppa.launchpad.net/sane-project/sane-git/ubuntu focal InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://ppa.launchpad.net/sane-project/sane-release/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY DDEAC554C101175B
E: The repository 'http://ppa.launchpad.net/sane-project/sane-release/ubuntu focal InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

I tried adding the fingerprint B5904B171A07B33815710C02DDEAC554C101175B through Update Manager and receive the following error:

Failed to download repository information check your internet connection.

W:GPG error: http://ppa.launchpad.net/sane-project/sane-git/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY DDEAC554C101175B, E:The repository 'http://ppa.launchpad.net/sane-project/sane-git/ubuntu focal InRelease' is not signed., W:Updating from such a repository can't be done securely, and is therefore disabled by default., W:See apt-secure(8) manpage for repository creation and user configuration details., W:GPG error: http://ppa.launchpad.net/sane-project/sane-release/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY DDEAC554C101175B, E:The repository 'http://ppa.launchpad.net/sane-project/sane-release/ubuntu focal InRelease' is not signed.

 

1. Is there a recommended way I can import this unsigned key? I have also tried importing the GPG signature with "apt-key add" and no joy.