I know the last comment is a month old now, but google is still driving people here for an answer. I found this on the web: http://www.namhuy.net/3116/how-to-fix-gpg-error-no_pubkey-in-ubuntu.html
$ sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 40976EAF437D05B5 Run this command for each hex key you need to download. replace "40976EAF437D05B5" with the appropriate key. I had to do it three times, but it worked for me. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apt in Ubuntu. https://bugs.launchpad.net/bugs/1263540 Title: Apt-get reports NO_PUBKEY gpg error for keys that are present in trusted.gpg. Status in APT: New Status in “apt” package in Ubuntu: Confirmed Bug description: Ubuntu 13.10 apt 0.9.9.1~ubuntu3 'apt-get update' has started showing several warnings like the following, even though the keys are present: W: GPG error: http://us.archive.ubuntu.com saucy Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32 'apt-key list' shows the keys in question in its output... pub 1024D/437D05B5 2004-09-12 uid Ubuntu Archive Automatic Signing Key <ftpmas...@ubuntu.com> sub 2048g/79164387 2004-09-12 pub 4096R/C0B21F32 2012-05-11 uid Ubuntu Archive Automatic Signing Key (2012) <ftpmas...@ubuntu.com> ...and its output begins with the following: gpg: keyblock resource `/etc/apt/trusted.gpg.d//webupd8team-y-ppa- manager.gpg': resource limit I see the same gpg message when I manually update/remove/add the keys in question. E.g.: $ sudo apt-key update gpg: keyblock resource `/etc/apt/trusted.gpg.d//webupd8team-java.gpg': resource limit gpg: keyblock resource `/etc/apt/trusted.gpg.d//webupd8team-y-ppa-manager.gpg': resource limit gpg: key 437D05B5: "Ubuntu Archive Automatic Signing Key <ftpmas...@ubuntu.com>" not changed gpg: key FBB75451: "Ubuntu CD Image Automatic Signing Key <cdim...@ubuntu.com>" not changed gpg: key C0B21F32: "Ubuntu Archive Automatic Signing Key (2012) <ftpmas...@ubuntu.com>" not changed gpg: key EFE21092: "Ubuntu CD Image Automatic Signing Key (2012) <cdim...@ubuntu.com>" not changed gpg: Total number processed: 4 gpg: unchanged: 4 I asked about the "resource limit" message on the gnupg-users mailing list... http://www.mail-archive.com/gnupg-users@gnupg.org/msg23300.html Based on Werner Koch's (the dev) answer... http://www.mail-archive.com/gnupg-users@gnupg.org/msg23302.html ...the secure apt related programs might be making gpg use more than the maximum number of keyrings that it can handle. To manage notifications about this bug go to: https://bugs.launchpad.net/apt/+bug/1263540/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
