Comment 0 for bug 1263540

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 <email address hidden>
sub 2048g/79164387 2004-09-12

pub 4096R/C0B21F32 2012-05-11
uid Ubuntu Archive Automatic Signing Key (2012) <email address hidden>

...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 updated/removed/added 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 <email address hidden>" not changed
gpg: key FBB75451: "Ubuntu CD Image Automatic Signing Key <email address hidden>" not changed
gpg: key C0B21F32: "Ubuntu Archive Automatic Signing Key (2012) <email address hidden>" not changed
gpg: key EFE21092: "Ubuntu CD Image Automatic Signing Key (2012) <email address hidden>" not changed
gpg: Total number processed: 4
gpg: unchanged: 4

I asked about the "resource limit" message on the gnupg-users mailing list...
http://<email address hidden>/msg23300.html
Based on Werner Koch's (the dev) answer...
http://<email address hidden>/msg23302.html
...the secure apt related programs might be making gpg use more than the maximum number of keyrings that it can handle.