Last night I started seeing a strange issue with using Android's repo on my Ubuntu machine:
$ repo sync info: A new version of repo is available
object e76efdd7b342577c40aa271fa5ded9d66a783a9b
type commit tag v1.12.4 tagger Conley Owens <cco3@android.com> 1380645867 -0700
repo 1.12.4
gpg: Signature made Tue Oct 1 12:44:27 2013 EDT using RSA key ID 692B382C
gpg: Can't check signature: public key not found error: could not verify the tag 'v1.12.4'