Get Ubuntu release keys

gistfile1.txt

Website with keys: http://releases.ubuntu.com/xenial/

# wget  http://releases.ubuntu.com/xenial/SHA256SUMS.gpg
# wget  http://releases.ubuntu.com/xenial/SHA256SUMS

[root@pto-centos pto]# gpg --keyid-format long --verify SHA256SUMS.gpg SHA256SUMS
gpg: Signature made Thu 28 Feb 2019 05:54:26 PM CET
gpg:                using DSA key 46181433FBB75451
gpg: Can't check signature: No public key
gpg: Signature made Thu 28 Feb 2019 05:54:26 PM CET
gpg:                using RSA key D94AA3F0EFE21092
gpg: Can't check signature: No public key


[root@pto-centos pto]# gpg --keyid-format long --keyserver hkp://keyserver.ubuntu.com --recv-keys 0x46181433FBB75451 0xD94AA3F0EFE21092
gpg: requesting key 46181433FBB75451 from hkp server keyserver.ubuntu.com
gpg: requesting key D94AA3F0EFE21092 from hkp server keyserver.ubuntu.com
gpg: key 46181433FBB75451: public key "Ubuntu CD Image Automatic Signing Key <cdimage@ubuntu.com>" imported
gpg: key D94AA3F0EFE21092: public key "Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com>" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 2
gpg:               imported: 2  (RSA: 1)


[root@pto-centos pto]# gpg --keyid-format long --list-keys --with-fingerprint 0x46181433FBB75451 0xD94AA3F0EFE21092
pub   1024D/46181433FBB75451 2004-12-30
      Key fingerprint = C598 6B4F 1257 FFA8 6632  CBA7 4618 1433 FBB7 5451
uid                          Ubuntu CD Image Automatic Signing Key <cdimage@ubuntu.com>

pub   4096R/D94AA3F0EFE21092 2012-05-11
      Key fingerprint = 8439 38DF 228D 22F7 B374  2BC0 D94A A3F0 EFE2 1092
uid                          Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com>

[root@pto-centos pto]#