Today pacman using signature check for packages for the security reason. If you want to disable this signature check you can read my previous posts. To enable it here's the step.
#pacman -Sy pacman
2. Generate some activity
If you still doing nothing on your pc, will long to generate, to make it fast just do this activity.
- move your mouse, do copy or paste
- type some command line related about "disk"
If you did that activity, your pacman key will generate under one minutes. See this my results on my laptops.
3. Now pacman-key is generated
you can continue to do pacman commands.
For the latest iso of archlinux, if you installing from the latest iso. The signature check is enabled by default. And when doing pacman -Syu or doing upgrading, the process is running without problem.
But if you installing archlinux from 2011 isos, you need upgrade pacman, then you must generate pacman key if you want to enable signature check. But if you still get error about GPG. You can set siglevel to never.
Enjoy archlinux rolling release.