When I try to upgrade my ubuntu 13.04 to 13.10, it gives the following error:
It was not possible to authenticate some packages. This may be a transient network problem. You may want to try again later. See below for a list of unauthenticated packages.
Also while downloading the files, I see such errors like:
Err http://in.archive.ubuntu.com saucy-backports/restricted Translation-en_IN
I tried the link to a similar question but that does not work. I don't think I have any troubles with the keys.