update process leads to "can't authenticate certain packages message

Please provide the output of the following commands

uname -a
lsb_release -crid
sudo dpkg --audit
sudo apt-get update

$ uname -a
Linux wunderkind 3.13.0-77-generic #121-Ubuntu SMP Wed Jan 20 10:50:59 UTC
2016 i686 athlon i686 GNU/Linux
------
lsb_release -crid
Distributor ID: Ubuntu
Description: Ubuntu 14.04.3 LTS
Release: 14.04
Codename: trusty
------------
The following packages are missing the md5sums control file in the
database, they need to be reinstalled:
 libjson0:i386 JSON manipulation library (transitional package)
----------------
Hit http://security.ubuntu.com trusty-security
InRelease
Ign http://archive.ubuntu.com trusty
InRelease
Get:1 http://archive.ubuntu.com trusty-updates InRelease [64.4 kB]
Hit http://security.ubuntu.com trusty-security/restricted i386 Packages
Hit http://security.ubuntu.com trusty-security/universe i386
Packages
Hit http://security.ubuntu.com trusty-security/multiverse i386
Packages
Get:2 http://archive.ubuntu.com trusty-proposed InRelease [212
kB]
Hit http://security.ubuntu.com trusty-security/main i386 Packages
Hit http://security.ubuntu.com trusty-security/main
Translation-en
Hit http://security.ubuntu.com trusty-security/multiverse
Translation-en
Hit http://security.ubuntu.com trusty-security/restricted
Translation-en
Get:3 http://archive.ubuntu.com trusty-backports InRelease [64.5
kB]
Hit http://security.ubuntu.com trusty-security/universe
Translation-en
Hit http://archive.ubuntu.com trusty
Release.gpg
Get:4 http://archive.ubuntu.com trusty-updates/restricted i386 Packages
[15.6 kB]
Get:5 http://archive.ubuntu.com trusty-updates/universe i386 Packages [335
kB]
Get:6 http://archive.ubuntu.com trusty-updates/multiverse i386 Packages
[13.1 kB]
Get:7 http://archive.ubuntu.com trusty-updates/main i386 Packages [663 kB]
Hit http://archive.ubuntu.com trusty-updates/main Translation-en
Hit http://archive.ubuntu.com trusty-updates/multiverse Translation-en
Hit http://archive.ubuntu.com trusty-updates/restricted Translation-en
Hit http://archive.ubuntu.com trusty-updates/universe Translation-en
Get:8 http://archive.ubuntu.com trusty-proposed/restricted i386 Packages
[3,661 B]
Get:9 http://archive.ubuntu.com trusty-proposed/universe i386 Packages
[22.0 kB]
Get:10 http://archive.ubuntu.com trusty-proposed/multiverse i386 Packages
[733 B]
Get:11 http://archive.ubuntu.com trusty-proposed/main i386 Packages [140
kB]
Get:12 http://archive.ubuntu.com trusty-proposed/main Translation-en [56.9
kB]
Get:13 http://archive.ubuntu.com trusty-proposed/multiverse Translation-en
[539 B]
Get:14 http://archive.ubuntu.com trusty-proposed/restricted Translation-en
[746 B]
Get:15 http://archive.ubuntu.com trusty-proposed/universe Translation-en
[19.7 kB]
Get:16 http://archive.ubuntu.com trusty-backports/universe i386 Packages
[39.8 kB]
Get:17 http://archive.ubuntu.com trusty-backports/multiverse i386 Packages
[1,552 B]
Get:18 http://archive.ubuntu.com trusty-backports/main i386 Packages [9,426
B]
Get:19 http://archive.ubuntu.com trusty-backports/restricted i386 Packages
[28 B]
Hit http://archive.ubuntu.com trusty-backports/main
Translation-en
Hit http://archive.ubuntu.com trusty-backports/multiverse
Translation-en
Hit http://archive.ubuntu.com trusty-backports/restricted
Translation-en
Hit http://archive.ubuntu.com trusty-backports/universe
Translation-en
Hit http://archive.ubuntu.com trusty
Release
Hit http://archive.ubuntu.com trusty/main
Sources
Hit http://archive.ubuntu.com trusty/universe
Sources
Hit http://archive.ubuntu.com trusty/restricted
Sources
Hit http://archive.ubuntu.com trusty/multiverse
Sources
Hit http://archive.ubuntu.com trusty/main i386
Packages
Hit http://archive.ubuntu.com trusty/universe i386
Packages
Hit http://archive.ubuntu.com trusty/restricted i386
Packages
Hit http://archive.ubuntu.com trusty/multiverse i386
Packages
Hit http://archive.ubuntu.com trusty/main
Translation-en
Hit http://archive.ubuntu.com trusty/multiverse
Translation-en
Hit http://archive.ubuntu.com trusty/restricted
Translation-en
Hit http://archive.ubuntu.com trusty/universe
Translation-en
Ign http://archive.ubuntu.com trusty/main
Translation-en_US
Ign http://archive.ubuntu.com trusty/multiverse
Translation-en_US
Ign http://archive.ubuntu.com trusty/restricted
Translation-en_US
Ign http://archive.ubuntu.com trusty/universe
Translation-en_US
Fetched 1,664 kB in 26s (61.6
kB/s)
Reading package lists... Done

On Sat, Jan 30, 2016 at 7:56 AM, Manfred Hampl <
<email address hidden>> wrote:

> Your question #284154 on Ubuntu changed:
> https://answers.launchpad.net/ubuntu/+question/284154
>
> Status: Open => Needs information
>
> Manfred Hampl requested more information:
> Please provide the output of the following commands
>
> uname -a
> lsb_release -crid
> sudo dpkg --audit
> sudo apt-get update
>
> --
> To answer this request for more information, you can either reply to
> this email or enter your reply at the following page:
> https://answers.launchpad.net/ubuntu/+question/284154
>
> You received this question notification because you asked the question.
>

to correct the small problem that I see in your output (missing md5sums file), please issue the command

sudo apt-get install --reinstall libjson0:i386

and cop/paste all output into the question document.

Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not
upgraded.
Need to get 0 B/1,078 B of archives.
After this operation, 0 B of additional disk space will be used.
(Reading database ... 206690 files and directories currently installed.)
Preparing to unpack .../libjson0_0.11-3ubuntu1.2_i386.deb ...
Unpacking libjson0:i386 (0.11-3ubuntu1.2) over (0.11-3ubuntu1.2) ...
Setting up libjson0:i386 (0.11-3ubuntu1.2) ...

On Sat, Jan 30, 2016 at 12:08 PM, Manfred Hampl <
<email address hidden>> wrote:

> Your question #284154 on Ubuntu changed:
> https://answers.launchpad.net/ubuntu/+question/284154
>
> Status: Open => Needs information
>
> Manfred Hampl requested more information:
> to correct the small problem that I see in your output (missing md5sums
> file), please issue the command
>
> sudo apt-get install --reinstall libjson0:i386
>
> and cop/paste all output into the question document.
>
> --
> To answer this request for more information, you can either reply to
> this email or enter your reply at the following page:
> https://answers.launchpad.net/ubuntu/+question/284154
>
> You received this question notification because you asked the question.
>

Ok, I do not see any problem about problems with authenticating.
When and where did you see such message?

Software updater does its thing...
and then says: My system is up to date _but_
an upgrade to Vile Vervet is available; do I want?

I want. The upgrade routine runs, downloads heaps of repository
information, digests that for awhile, and then I get the 'can't be
authenticated' message.

I don't get an option to say 'Go ahead & use what you've got!' -- I get an
"okay" [No, this isn't okay!] button to push.
& then I'm restored to my former 14.04 system (which still lacks the
cinnamon desktop I'd like to install here.)
=========
[I'm going to just put 15.10 on the other partition, now that my
replacement dvd drive just got delivered... but I've been running into this
14.04 online-upgrade bug for quite awhile now.]

On Sat, Jan 30, 2016 at 1:12 PM, Manfred Hampl <
<email address hidden>> wrote:

> Your question #284154 on Ubuntu changed:
> https://answers.launchpad.net/ubuntu/+question/284154
>
> Status: Open => Needs information
>
> Manfred Hampl requested more information:
> Ok, I do not see any problem about problems with authenticating.
> When and where did you see such message?
>
> --
> To answer this request for more information, you can either reply to
> this email or enter your reply at the following page:
> https://answers.launchpad.net/ubuntu/+question/284154
>
> You received this question notification because you asked the question.
>

Ok, understood.

two remarks:
1. Why do you want to upgrade to vivid at all? That version is going into end of life status next week (Feb 4, 2016).
In my opinion the better decision would be to wait until Ubuntu 16.04 is published (in April). You would be able to do a direct upgrade from 14.04 to 16.04 then

2. Please provide the full output of that 'not authenticated' message.

Sorry, yesterday I received the dvd drive I'd ordered & directly installed
15.10, whereupon I promptly returned the critter to my wife...

It was a long list of packages with nothing obvious in common (may have
used libjson? -- which was one package evidently fnurgled at the time you
suggested reinstalling it)

Unless someone else runs into the same problem, seems to be a dead issue as
you say.

On Sat, Jan 30, 2016 at 1:37 PM, Manfred Hampl <
<email address hidden>> wrote:

> Your question #284154 on Ubuntu changed:
> https://answers.launchpad.net/ubuntu/+question/284154
>
> Status: Open => Answered
>
> Manfred Hampl proposed the following answer:
> Ok, understood.
>
> two remarks:
> 1. Why do you want to upgrade to vivid at all? That version is going into
> end of life status next week (Feb 4, 2016).
> In my opinion the better decision would be to wait until Ubuntu 16.04 is
> published (in April). You would be able to do a direct upgrade from 14.04
> to 16.04 then
>
> 2. Please provide the full output of that 'not authenticated' message.
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
> https://answers.launchpad.net/ubuntu/+question/284154/+confirm?answer_id=6
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/ubuntu/+question/284154
>
> You received this question notification because you asked the question.
>

There is currently a similar problem for two other people https://answers.launchpad.net/ubuntu/+question/284214 but I do not know the root cause.