Governments today are rank amateurs it seems
If the Authorities present DNA 'evidence' to a jury, what jury won't convict on that basis alone?
Very few, I'd wager. Very few jurors will sufficiently well informed to argue about the validity of the findings themselves or follow the Defence's technical rebuttal - "It was his/her DNA and we found it at the crime scene" is enough for most to convict and the rest of the evidence (and the case itself) is merely a tedious waste of their time from that point on.
Yet most juries will understand more about DNA than they will about hashing, elliptical curves, salting, rainbow tables, assymetric functions and lots of other mindnumbing mathematical stuff that just makes their heads swim.
So, if David Kelly commited suicide,
by (oh, so characteristically) sticking a needle in his arm,
in the middle of a field,
miles from home,
just after he was about to divulge important information,
that might have spelled trouble for some high ups,
and no-one says "Hang on a minute!"
I'm sure TPTB can arrange to plant fake information on a fake device that is claimed to belong to someone.
Or simply state that they got the information from such device but that said device was destroyed in the process.
Or even just present the still encrypted device and say "Here. We got this off it, but we can't tell you how because 'National Security' - you'll just have to take our word for it."
Why do they even bother trying to intercept people's communications?
If you're TPTB and you don't like someone, just fit them up.
Who's ever gonna be in a position to do more than write a 'conspiracy theory' and ask awkward questions that need never be answered anyway (because 'National Security')?
Seriously, robber barons these days - Ghengis Kahn wouldn't recognise them!