$ wget http://archive.ubuntu.com/ubuntu/dists/trusty-updates/main/installer-i386/current/images/netboot/mini.iso
--2016-03-24 12:18:28-- http://archive.ubuntu.com/ubuntu/dists/trusty-updates/main/installer-i386/current/images/netboot/mini.iso
Resolving archive.ubuntu.com (archive.ubuntu.com)... 2001:67c:1360:8001::17, 2001:67c:1562::17, 2001:67c:1562::16, ...
Connecting to archive.ubuntu.com (archive.ubuntu.com)|2001:67c:1360:8001::17|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 34603008 (33M) [application/x-iso9660-image]
Saving to: ‘mini.iso’
mini.iso 100%[===============================================================================>] 33.00M 1.17MB/s in 29s
2016-03-24 12:18:56 (1.15 MB/s) - ‘mini.iso’ saved [34603008/34603008]
tj@hephaestion:/tmp$ wget http://archive.ubuntu.com/ubuntu/dists/trusty-updates/main/installer-i386/current/images/SHA1SUMS
--2016-03-24 12:19:24-- http://archive.ubuntu.com/ubuntu/dists/trusty-updates/main/installer-i386/current/images/SHA1SUMS
Resolving archive.ubuntu.com (archive.ubuntu.com)... 2001:67c:1562::15, 2001:67c:1562::14, 2001:67c:1560:8001::11, ...
Connecting to archive.ubuntu.com (archive.ubuntu.com)|2001:67c:1562::15|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 14002 (14K)
Saving to: ‘SHA1SUMS’
SHA1SUMS 100%[===============================================================================>] 13.67K --.-KB/s in 0.01s
2016-03-24 12:19:25 (1.31 MB/s) - ‘SHA1SUMS’ saved [14002/14002]
tj@hephaestion:/tmp$ wget http://archive.ubuntu.com/ubuntu/dists/trusty-updates/main/installer-i386/current/images/SHA1SUMS.gpg
--2016-03-24 12:19:28-- http://archive.ubuntu.com/ubuntu/dists/trusty-updates/main/installer-i386/current/images/SHA1SUMS.gpg
Resolving archive.ubuntu.com (archive.ubuntu.com)... 2001:67c:1562::16, 2001:67c:1562::15, 2001:67c:1562::14, ...
Connecting to archive.ubuntu.com (archive.ubuntu.com)|2001:67c:1562::16|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 933
Saving to: ‘SHA1SUMS.gpg’
SHA1SUMS.gpg 100%[===============================================================================>] 933 --.-KB/s in 0s
2016-03-24 12:19:28 (91.7 MB/s) - ‘SHA1SUMS.gpg’ saved [933/933]
tj@hephaestion:/tmp$ gpg --verify --keyring /etc/apt/trusted.gpg SHA1SUMS.gpg SHA1SUMS
gpg: Signature made Wed 17 Feb 2016 08:32:02 GMT using DSA key ID 437D05B5
gpg: Good signature from "Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 6302 39CC 130E 1A7F D81A 27B1 4097 6EAF 437D 05B5
gpg: Signature made Wed 17 Feb 2016 08:32:02 GMT using RSA key ID C0B21F32
gpg: Good signature from "Ubuntu Archive Automatic Signing Key (2012) <ftpmaster@ubuntu.com>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 790B C727 7767 219C 42C8 6F93 3B4F E6AC C0B2 1F32
tj@hephaestion:/tmp$ mkdir netboot; mv mini.iso netboot/
tj@hephaestion:/tmp$ grep '\./netboot/mini.iso' SHA1SUMS | sha1sum -c
./netboot/mini.iso: OK