

The apt packaging system has a set of trusted keys that determine whether a package can be authenticated and therefore trusted to be installed on the system. For example: $ sudo apt-get upgradeĮ: Some packages could not be authenticated If these errors aren’t fixed, apt will have problems when installing or upgrading packages. W: GPG error: 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: 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: trusty-security Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32 There are times when running apt-get update in Ubuntu will result in error messages such as the following: $ sudo apt-get update
