GPG ERROR NO_PUBKEY: WARNUNG: Die folgenden Pakete können nicht authentifiziert werden! [geschlossen]

Ich habe gerade einige seltsame Fehler in Bezug auf GPG-Schlüssel angestarrt. Ich habe nämlich gerade hinzugefügt ppa:ubuntu-toolchain-r/testund wollte updaten und danach habe ich folgendes bekommen:

W: GPG error: http://extras.ubuntu.com trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192
W: GPG error: http://archive.canonical.com trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32
W: GPG error: http://qgis.org trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 030561BEDD45F6C3
W: GPG error: http://dl.google.com stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A040830F7FAC5991
W: GPG error: http://dl.google.com stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A040830F7FAC5991
W: GPG error: http://archive.ubuntu.com trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32
W: GPG error: http://archive.ubuntu.com trusty-updates Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32
W: GPG error: http://archive.ubuntu.com trusty-security Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32

Ich habe versucht, es auf zwei Arten zu lösen ( hier bereitgestellt )

for key in 40976EAF437D05B5 3B4FE6ACC0B21F32 A040830F7FAC5991 030561BEDD45F6C3 16126D3A3E5C1192  ; do sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys $key ; done

aber das hat nicht geholfen (die gleichen Fehler kamen immer wieder mit den gleichen Schlüsseln), also habe ich versucht, dies zu tun:

sudo add-apt-repository ppa:webupd8team/y-ppa-manager
sudo apt-get update
sudo apt-get install y-ppa-manager

aber ich habe das, was meine Augen geöffnet:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  launchpad-getkeys libvte-common libvte9 python-keyring python-launchpadlib
  python-lazr.restfulclient python-lazr.uri python-oauth python-secretstorage
  python-simplejson python-vte python-wadllib xclip yad
Suggested packages:
  python-gdata python-keyczar python-kde4 python-testresources
  python-secretstorage-doc
The following NEW packages will be installed:
  launchpad-getkeys libvte-common libvte9 python-keyring python-launchpadlib
  python-lazr.restfulclient python-lazr.uri python-oauth python-secretstorage
  python-simplejson python-vte python-wadllib xclip y-ppa-manager yad
0 upgraded, 15 newly installed, 0 to remove and 29 not upgraded.
Need to get 915 kB of archives.
After this operation, 4,515 kB of additional disk space will be used.
Do you want to continue? [Y/n] Y
WARNING: The following packages cannot be authenticated!
  libvte-common libvte9 python-keyring python-lazr.uri python-simplejson
  python-wadllib python-oauth python-lazr.restfulclient python-launchpadlib
  python-secretstorage python-vte xclip
Install these packages without verification? [y/N]

Führen Sie den Befehl aus:

sudo apt-get update

Führen Sie für jeden 16-stelligen Schlüssel, der als fehlend gemeldet wird, Folgendes aus, wobei der Schlüssel ersetzt wird:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys ABCDEFGH12345678