andreas@corrino:~/iso$ curl -LJOO http://se.archive.ubuntu.com/mirror/cdimage.ubuntu.com/xubuntu/releases/15.04/release/SHA256SUMS{,.gpg}
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 195 100 195 0 0 487 0 --:--:-- --:--:-- --:--:-- 488
100 198 100 198 0 0 1288 0 --:--:-- --:--:-- --:--:-- 0
andreas@corrino:~/iso$ gpg --no-default-keyring --keyring /usr/share/keyrings/ubuntu-archive-keyring.gpg --verify SHA256SUMS.gpg SHA256SUMS
gpg: Signatur gjordes tor 23 apr 2015 12:59:28 CEST med DSA nyckel-id FBB75451
gpg: Korrekt signatur från "Ubuntu CD Image Automatic Signing Key <cdimage@ubuntu.com>"
andreas@corrino:~/iso$