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.
Err http://in.archive.ubuntu.com saucy-backports/restricted Translation-en_IN
我尝试了the link to a similar question，但这不起作用。我认为按键没有任何麻烦。
Important Security Notice
This answer will disable an critical security feature in Ubuntu. It will stop Ubuntu checking packages are the the same as they were when they were built.
This could mean your updates are compromised or corrupt.
This could mean there’s just a bug in the way Ubuntu’s release upgrades are handled.
I’m not saying you should never do this, I’m just asking you to be aware of what you’re doing. And put things back after you upgrade. Don’t leave
— Oli, Ask Ubuntu mod.