The error I received when performing 'sudo do-release-upgrade' was:

Error authenticating some packages
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.
accountsservice
acpi-support
activity-log-manager-common
activity-log-manager-control-center
alsa-base
alsa-utils
apache2
apache2-mpm-worker
apache2-utils
apache2.2-bin
apache2.2-common
apparmor
apparmor-utils
appmenu-gtk
appmenu-gtk3
apport
apport-gtk
apport-symptoms
apt
apt-transport-https
apt-utils
apt-xapian-index
aptdaemon
aptdaemon-data
aptitude
at-spi2-core
avahi-autoipd
avahi-daemon
avahi-utils
bamfdaemon
base-files
bash
bash-completion
bc
bind9
bind9-doc
bind9-host
bind9utils
binutils
bluez
bluez-alsa
bluez-cups
bluez-gstreamer
bogofilter
bogofilter-bdb
bogofilter-common
brasero
brasero-cdrkit
brasero-common
bsd-mailx
bsdutils
build-essential
busybox-initramfs
busybox-static
ca-certificates
checkbox
checkbox-gtk
checkbox-qt
cifs-utils
colord
compiz
compiz-core
compiz-fusion-plugins-main
compiz-gnome
compiz-plugins
compiz-plugins-default
compiz-plugins-main
compiz-plugins-main-default
consolekit
coreutils
cpio
cron
cups
cups-bsd
cups-client
cups-common
cups-driver-gutenprint
cups-filters
cups-pk-helper
cups-ppdc
dbus
dbus-x11
dc
dconf-gsettings-backend
dconf-service
deja-dup
desktop-file-utils
dhcp3-client
dhcp3-common
dmidecode
dmsetup
dnsmasq-base
dnsutils
dosfstools
dpkg
dpkg-dev
duplicity
e2fslibs
e2fsprogs
ecryptfs-utils
empathy
empathy-common
eog
evince
evince-common
evolution-data-server
evolution-data-server-common
exim4
exim4-base
exim4-config
exim4-daemon-light
file
firefox
firefox-gnome-support
firefox-locale-en
fontconfig
fontconfig-config
fonts-liberation
fonts-opensymbol
foomatic-filters
fuse
fuse-utils
gamin
gcalctool
gdb
gdm
geoclue-ubuntu-geoip
ghostscript
ghostscript-cups
ghostscript-x
ginn
gir1.2-appindicator3-0.1
gir1.2-atspi-2.0
gir1.2-dbusmenu-glib-0.4
gir1.2-dbusmenu-gtk-0.4
gir1.2-dee-1.0
gir1.2-gdkpixbuf-2.0
gir1.2-gnomebluetooth-1.0
gir1.2-gst-plugins-base-0.10
gir1.2-gtk-2.0
gir1.2-gtk-3.0
gir1.2-gtksource-3.0
gir1.2-gudev-1.0
gir1.2-javascriptcoregtk-3.0
gir1.2-launchpad-integration-3.0
gir1.2-panelapplet-4.0
gir1.2-pango-1.0
gir1.2-rb-3.0
gir1.2-totem-1.0
gir1.2-unity-5.0
gir1.2-webkit-3.0
glib-networking
glib-networking-common
glib-networking-services
gnome-accessibility-themes
gnome-bluetooth
gnome-control-center
gnome-control-center-data
gnome-desktop3-data
gnome-dictionary
gnome-games-data
gnome-icon-theme
gnome-icon-theme-full
gnome-keyring
gnome-media
gnome-online-accounts
gnome-orca
gnome-panel-data
gnome-power-manager
gnome-screenshot
gnome-settings-daemon
gnome-sudoku
gnomine
gnupg
gnupg-curl
gparted
gpgv
grub-common
grub-pc
grub-pc-bin
grub2-common
gstreamer0.10-alsa
gstreamer0.10-gconf
gstreamer0.10-plugins-base
gstreamer0.10-plugins-base-apps
gstreamer0.10-plugins-good
gstreamer0.10-pulseaudio
gstreamer0.10-x
gtk2-engines-pixbuf
gvfs
gvfs-backends
gvfs-bin
gvfs-common
gvfs-daemons
gvfs-fuse
gvfs-libs
gwibber
gwibber-service
gwibber-service-facebook
gwibber-service-identica
gwibber-service-twitter
hdparm
hpijs
hplip
hplip-data
ifupdown
im-switch
imagemagick
imagemagick-common
indicator-messages
indicator-sound
indicator-status-provider-mc5
initramfs-tools
initramfs-tools-bin
initscripts
iproute
iptables
isc-dhcp-client
isc-dhcp-common
jockey-common
jockey-gtk
kate-data
katepart
kde-runtime
kde-runtime-data
kdebase-runtime
kdelibs-bin
kdelibs5
kdelibs5-data
kdelibs5-plugins
kdepim-runtime
kdepimlibs-kio-plugins
kdepimlibs5
kdoctools
krb5-locales
landscape-client-ui-install
landscape-common
language-pack-en
language-pack-en-base
language-selector
language-selector-common
language-selector-gnome
launchpad-integration
libaccountsservice0
libakonadi-calendar4
libakonadi-contact4
libakonadi-kabc4
libakonadi-kcal4
libakonadi-kde4
libakonadi-kmime4
libakonadi-notes4
libapparmor-perl
libapparmor1
libappindicator0.1-cil
libappindicator1
libappindicator3-1
libapt-inst1.4
libapt-pkg4.12
libarchive12
libart-2.0-2
libasn1-8-heimdal
libasound2
libatspi2.0-0
libaudio2
libaudiofile1
libavahi-client3
libavahi-common-data
libavahi-common3
libavahi-core7
libavahi-glib1
libavahi-gobject0
libavahi-ui-gtk3-0
libavahi-ui0
libavcodec53
libavutil51
libbamf0
libbamf3-0
libbind9-80
libblkid1
libbluetooth3
libbonobo2-0
libbonobo2-common
libbonoboui2-0
libbonoboui2-common
libbrasero-media3-1
libc-bin
libc-dev-bin
libc6
libc6-dev
libcairo-gobject2
libcairo2
libcamel-1.2-29
libcdt4
libck-connector0
libclutter-1.0-0
libclutter-1.0-common
libcolord1
libcomerr2
libcroco3
libcups2
libcupscgi1
libcupsdriver1
libcupsfilters1
libcupsimage2
libcupsmime1
libcupsppdc1
libcurl3
libcurl3-gnutls
libcurl3-nss
libdbus-1-3
libdbus-glib-1-2
libdbusmenu-glib4
libdbusmenu-gtk3-4
libdbusmenu-gtk4
libdconf-dbus-1-0
libdconf0
libdecoration0
libdee-1.0-4
libdevmapper-event1.02.1
libdevmapper1.02.1
libdjvulibre-text
libdjvulibre21
libdns81
libdpkg-perl
libdrm-intel1
libdrm-nouveau1a
libdrm-radeon1
libdrm2
libdvdnav4
libdvdread4
libebackend-1.2-1
libebook-1.2-12
libecal-1.2-10
libecryptfs0
libedata-book-1.2-11
libedata-cal-1.2-13
libedataserver-1.2-15
libedataserverui-3.0-1
libelf1
libevent-2.0-5
libevince3-3
libexif12
libexpat1
libflac8
libfontconfig1
libframe6
libfreerdp-plugins-standard
libfreerdp1
libfreetype6
libfs6
libfuse2
libgadu3
libgail-3-0
libgail-common
libgail18
libgamin0
libgc1c2
libgck-1-0
libgcr-3-1
libgcr-3-common
libgcrypt11
libgdict-1.0-6
libgdict-common
libgdk-pixbuf2.0-0
libgdk-pixbuf2.0-common
libgeis1
libgl1-mesa-dri
libgl1-mesa-glx
libglade2-0
libglapi-mesa
libglib2.0-0
libglib2.0-bin
libglib2.0-data
libglu1-mesa
libgnome-bluetooth8
libgnome-control-center1
libgnome-desktop-3-2
libgnome2-0
libgnome2-bin
libgnome2-common
libgnomecanvas2-0
libgnomecanvas2-common
libgnomekbd-common
libgnomekbd7
libgnomevfs2-0
libgnomevfs2-common
libgnomevfs2-extra
libgnutls26
libgoa-1.0-0
libgoa-1.0-common
libgpgme++2
libgpgme11
libgphoto2-2
libgphoto2-l10n
libgphoto2-port0
libgrail5
libgraph4
libgrip0
libgs9
libgs9-common
libgssapi-krb5-2
libgssapi3-heimdal
libgstreamer-plugins-base0.10-0
libgtk-3-0
libgtk-3-bin
libgtk-3-common
libgtk2.0-0
libgtk2.0-bin
libgtk2.0-common
libgtkhtml-4.0-0
libgtkhtml-4.0-common
libgtkhtml-editor-4.0-0
libgtksourceview-3.0-0
libgtksourceview-3.0-common
libgtksourceview2.0-0
libgtksourceview2.0-common
libgudev-1.0-0
libgutenprint2
libgvc5
libgwibber-gtk2
libgwibber2
libhcrypto4-heimdal
libheimbase1-heimdal
libheimntlm0-heimdal
libhpmud0
libhx509-5-heimdal
libicu48
libindicator-messages-status-provider1
libisc83
libisccc80
libisccfg82
libjasper1
libjavascriptcoregtk-1.0-0
libjavascriptcoregtk-3.0-0
libjpeg-turbo8
libjpeg62
libjson0
libk5crypto3
libkabc4
libkalarmcal2
libkatepartinterfaces4
libkblog4
libkcal4
libkcalcore4
libkcalutils4
libkcmutils4
libkde3support4
libkdeclarative5
libkdecore5
libkdesu5
libkdeui5
libkdewebkit5
libkdnssd4
libkemoticons4
libkfile4
libkholidays4
libkhtml5
libkidletime4
libkimap4
libkimproxy4
libkio5
libkjsapi4
libkjsembed4
libkldap4
libkmbox4
libkmediaplayer4
libkmime4
libknewstuff2-4
libknewstuff3-4
libknotifyconfig4
libkntlm4
libkparts4
libkpimidentities4
libkpimtextedit4
libkpimutils4
libkprintutils4
libkpty4
libkrb5-26-heimdal
libkrb5-3
libkrb5support0
libkresources4
libkrosscore4
libkrossui4
libktexteditor4
libktnef4
libkutils4
libkworkspace4abi1
libkxmlrpcclient4
liblaunchpad-integration-3.0-1
liblaunchpad-integration-common
liblaunchpad-integration1
liblaunchpad-integration1.0-cil
liblcms2-2
libldap-2.4-2
liblightdm-gobject-1-0
liblockfile-bin
liblockfile1
liblua5.1-0
liblvm2app2.2
liblwres80
libmagic1
libmagickcore4
libmagickcore4-extra
libmagickwand4
libmailtransport4
libmicroblog4
libminiupnpc8
libmission-control-plugins0
libmono-cairo2.0-cil
libmono-cairo4.0-cil
libmono-corlib2.0-cil
libmono-corlib4.0-cil
libmono-csharp4.0-cil
libmono-data-tds2.0-cil
libmono-data-tds4.0-cil
libmono-i18n-west2.0-cil
libmono-i18n-west4.0-cil
libmono-i18n4.0-cil
libmono-messaging2.0-cil
libmono-posix2.0-cil
libmono-posix4.0-cil
libmono-security2.0-cil
libmono-security4.0-cil
libmono-sharpzip2.84-cil
libmono-sharpzip4.84-cil
libmono-simd4.0-cil
libmono-sqlite2.0-cil
libmono-sqlite4.0-cil
libmono-system-configuration4.0-cil
libmono-system-core4.0-cil
libmono-system-data-linq2.0-cil
libmono-system-data2.0-cil
libmono-system-data4.0-cil
libmono-system-drawing4.0-cil
libmono-system-enterpriseservices4.0-cil
libmono-system-messaging2.0-cil
libmono-system-runtime2.0-cil
libmono-system-security4.0-cil
libmono-system-transactions4.0-cil
libmono-system-web-applicationservices4.0-cil
libmono-system-web-services4.0-cil
libmono-system-web2.0-cil
libmono-system-web4.0-cil
libmono-system-xml4.0-cil
libmono-system2.0-cil
libmono-system4.0-cil
libmono-wcf3.0-cil
libmono-web4.0-cil
libmono2.0-cil
libmount1
libmtp-common
libmtp-runtime
libmtp9
libmysqlclient18
libnautilus-extension1a
libneon27-gnutls
libnepomuk4
libnepomukdatamanagement4
libnepomukquery4a
libnepomuksync4
libnepomukutils4
libnih-dbus1
libnih1
libnm-glib-vpn1
libnm-glib4
libnm-gtk-common
libnm-gtk0
libnm-util2
libnspr4
libnspr4-0d
libnss3
libnss3-1d
libnux-2.0-0
libnux-2.0-common
liborbit2
liboverlay-scrollbar-0.2-0
liboverlay-scrollbar3-0.2-0
libpam-ck-connector
libpam-gnome-keyring
libpam-modules
libpam-modules-bin
libpam-runtime
libpam-smbpass
libpam-winbind
libpam0g
libpanel-applet-4-0
libpango1.0-0
libparted0debian1
libpathplan4
libpci3
libpciaccess0
libpcre3
libperl5.14
libpixman-1-0
libplasma3
libplymouth2
libpng12-0
libpolkit-agent-1-0
libpolkit-backend-1-0
libpolkit-gobject-1-0
libpoppler-glib8
libpoppler19
libpostproc52
libproxy1
libproxy1-plugin-gsettings
libproxy1-plugin-networkmanager
libpulse-mainloop-glib0
libpulse0
libpulsedsp
libpurple-bin
libpurple0
libpython2.7
libqgpgme1
libqt4-assistant
libqt4-dbus
libqt4-declarative
libqt4-designer
libqt4-help
libqt4-network
libqt4-opengl
libqt4-qt3support
libqt4-script
libqt4-scripttools
libqt4-sql
libqt4-sql-mysql
libqt4-sql-sqlite
libqt4-svg
libqt4-test
libqt4-webkit
libqt4-xml
libqt4-xmlpatterns
libqtbamf1
libqtcore4
libqtgui4
libraptor1
libraptor2-0
libraw5
libreoffice-base-core
libreoffice-calc
libreoffice-common
libreoffice-core
libreoffice-draw
libreoffice-emailmerge
libreoffice-gnome
libreoffice-gtk
libreoffice-help-en-us
libreoffice-impress
libreoffice-math
libreoffice-style-galaxy
libreoffice-style-human
libreoffice-style-tango
libreoffice-writer
librhythmbox-core5
libroken18-heimdal
librsvg2-2
librsvg2-common
libsane-hpaio
libsasl2-2
libsasl2-modules
libsdl1.2debian
libslp1
libsmbclient
libsndfile1
libsnmp-base
libsnmp15
libsolid4
libsqlite3-0
libss2
libssh-4
libssl0.9.8
libssl1.0.0
libsyncdaemon-1.0-1
libsyndication4
libtasn1-3
libtelepathy-glib0
libthreadweaver4
libtiff4
libtotem0
libudev0
libunity-2d-private0
libunity-core-5.0-5
libunity9
libupower-glib1
libusbmuxd1
libuuid1
libv4l-0
libv4lconvert0
libvncserver0
libwbclient0
libwebkitgtk-1.0-0
libwebkitgtk-1.0-common
libwebkitgtk-3.0-0
libwebkitgtk-3.0-common
libwind0-heimdal
libwmf0.2-7
libwmf0.2-7-gtk
libx11-6
libx11-data
libx11-xcb1
libxatracker1
libxcb-dri2-0
libxcb-glx0
libxcb-render0
libxcb-shape0
libxcb-shm0
libxcb-xv0
libxcb1
libxcursor1
libxext6
libxfixes3
libxfont1
libxi6
libxinerama1
libxkbfile1
libxml-libxml-perl
libxml-sax-perl
libxml2
libxml2-utils
libxp6
libxrandr2
libxrender1
libxres1
libxslt1.1
libxt6
libxtst6
libxv1
libxvmc1
libxxf86dga1
libxxf86vm1
libzeitgeist-1.0-1
light-themes
lightdm
linux-firmware
linux-headers-3.2.0-101
linux-headers-3.2.0-101-generic
linux-headers-generic
linux-headers-server
linux-image-3.2.0-101-generic
linux-image-server
linux-libc-dev
linux-server
linux-sound-base
login
lsb-base
lsb-release
mahjongg
make
man-db
mime-support
mono-2.0-gac
mono-4.0-gac
mono-gac
mono-runtime
mount
mountall
mtools
multiarch-support
mysql-client-core-5.5
mysql-common
mysql-server-core-5.5
nautilus
nautilus-data
nautilus-sendto-empathy
network-manager
network-manager-gnome
notify-osd
notify-osd-icons
ntfs-3g
ntfsprogs
ntpdate
nux-tools
nvidia-common
onboard
oneconf
openssh-client
openssh-server
openssl
overlay-scrollbar
oxygen-icon-theme
p7zip-full
parted
passwd
patch
pciutils
perl
perl-base
perl-modules
phonon-backend-gstreamer
pitivi
plasma-scriptengine-javascript
plymouth
plymouth-label
plymouth-theme-ubuntu-logo
plymouth-theme-ubuntu-text
plymouth-x11
pm-utils
policykit-1
policykit-1-gnome
poppler-utils
ppp
printer-driver-gutenprint
printer-driver-hpcups
printer-driver-hpijs
printer-driver-postscript-hp
printer-driver-ptouch
procps
psmisc
pulseaudio
pulseaudio-esound-compat
pulseaudio-module-bluetooth
pulseaudio-module-gconf
pulseaudio-module-x11
pulseaudio-utils
python
python-appindicator
python-apport
python-apt
python-apt-common
python-aptdaemon
python-aptdaemon-gtk
python-aptdaemon.gtk3widgets
python-aptdaemon.gtkwidgets
python-aptdaemon.pkcompat
python-avahi
python-central
python-crypto
python-cupshelpers
python-debtagshw
python-gi
python-gi-cairo
python-gobject
python-gst0.10
python-httplib2
python-imaging
python-kde4
python-keyring
python-launchpad-integration
python-lazr.restfulclient
python-libproxy
python-libxml2
python-minimal
python-openssl
python-piston-mini-client
python-problem-report
python-software-properties
python-ubuntu-sso-client
python-ubuntuone-client
python-ubuntuone-control-panel
python-ubuntuone-storageprotocol
python-uno
python-zeitgeist
python2.7
python2.7-minimal
qdbus
quadrapassel
remmina
remmina-common
remmina-plugin-rdp
remmina-plugin-vnc
resolvconf
rhythmbox
rhythmbox-data
rhythmbox-mozilla
rhythmbox-plugin-cdrecorder
rhythmbox-plugin-magnatune
rhythmbox-plugin-zeitgeist
rhythmbox-plugins
rhythmbox-ubuntuone
rsync
rsyslog
rtkit
samba
samba-common
samba-common-bin
samba-doc
screen-resolution-extra
seahorse
sessioninstaller
shared-mime-info
shotwell
simple-scan
smbclient
smbfs
software-center
software-properties-common
software-properties-gtk
software-properties-kde
ssh-askpass-gnome
ssl-cert
sudo
synaptic
system-config-printer-common
system-config-printer-gnome
system-config-printer-udev
sysv-rc
sysvinit-utils
tcpdump
telepathy-gabble
telepathy-idle
telepathy-mission-control-5
thunderbird
thunderbird-gnome-support
tomboy
totem
totem-common
totem-mozilla
totem-plugins
transmission-common
transmission-gtk
ttf-liberation
ttf-opensymbol
tzdata
ubufox
ubuntu-desktop
ubuntu-docs
ubuntu-keyring
ubuntu-minimal
ubuntu-sso-client
ubuntu-sso-client-gtk
ubuntu-standard
ubuntu-system-service
ubuntuone-client
ubuntuone-client-gnome
ubuntuone-control-panel
ubuntuone-installer
udev
udisks
unattended-upgrades
unity
unity-2d
unity-2d-common
unity-2d-panel
unity-2d-shell
unity-2d-spread
unity-common
unity-greeter
unity-lens-applications
unity-lens-files
unity-lens-music
unity-lens-video
unity-scope-musicstores
unity-scope-video-remote
unity-services
uno-libs3
unzip
update-manager
update-manager-core
update-manager-kde
update-notifier
update-notifier-common
upower
upstart
ure
usb-creator-common
usb-creator-gtk
usbmuxd
util-linux
uuid-runtime
vim
vim-common
vim-runtime
vim-tiny
vinagre
vino
w3m
wget
whoopsie
winbind
wpasupplicant
x11-common
x11-utils
xdiagnose
xkb-data
xorg
xscreensaver-data
xscreensaver-gl
xserver-common
xserver-xorg
xserver-xorg-core
xserver-xorg-input-all
xserver-xorg-input-evdev
xserver-xorg-input-synaptics
xserver-xorg-input-vmmouse
xserver-xorg-input-wacom
xserver-xorg-video-all
xserver-xorg-video-intel
xserver-xorg-video-nouveau
xserver-xorg-video-openchrome
xserver-xorg-video-qxl
xserver-xorg-video-vmware
xsltproc
xterm
xul-ext-ubufox
zeitgeist
zeitgeist-core
zenity
zenity-common