the times | Saturday September 5 2020 1GM 19
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The message did not contain much: just
a few small files randomly taken from a
physicist’s laptop.
Frankly, if the Russians wanted to in-
tercept and read it no one would have
minded. But neither they nor the CIA
would have been able to. The world’s in-
telligence agencies could, in fact, have
waited a century and applied the finest
supercomputers of 2120 to the problem
— and still been none the wiser.
Because this message, sent from the
centre of Bristol to locations beyond the
city’s suburbs, was quantum encrypted.
Scientists at Bristol University said
they had set up a quantum network,
using the laws of quantum physics to
make a significant step towards truly
uncrackable communications. At
present, most encrypted traffic on the
internet is sent using codes based on
the maths of prime numbers. They
work because encrypting using the
numbers is easy, but decrypting
requires calculations that are, for now,
beyond the skills of computers.
The problem is they may not be
Quantum science generates codes that won’t crack
Tom Whipple Science Editor beyond them forever. “If you have a
gaming computer, you can already
crack some of the weaker codes,” said
Siddarth Joshi, from Bristol University.
Even the strongest are likely to one day
be solvable, meaning that anything sent
now may one day be read.
This is why the most sensitive infor-
mation is still sent using “one time
pads”. In the safe of the British embassy
in Moscow, for example, there will be a
pad containing pages of random num-
bers. In a safe in Whitehall there is an
identical pad. Each time a message is
encrypted it uses up one page of num-
bers, which are destroyed at both ends.
This works but is, obviously, not prac-
tical each time you want to check your
bank balance. Neither is carrying
around a pad of random numbers a
sensible option for a spy. Quantum key
distribution is a way to create a one-
time pad without the need for a pad —
generating the numbers afresh for each
communication. It relies on entangle-
ment, which makes two particles
behave in the same way, even when sep-
arated. So if one user has one particle
they can be assured that any measure-
ment of its properties is reflected in the
second — a trick that can be used to
generate the same code in two places.
“Entanglement by itself is rather
simple,” said Dr Joshi. “If you have a
coin and I have a coin and these coins
happen to be part of an entangled pair,
then if you toss your coin and get heads
you know I do too.” In this way, you can
generate a secret key to encrypt a mes-
sage. “It is perfect security.”
Such methods have been used to
send messages before but keeping par-
ticles entangled over distance is not
simple and creating a true network is
normally costly as each person has to
be connected to each other. Dr Joshilikens it to children’s walkie talkies:
“They come in pairs, you have a trans-
mitter and a receiver.” This is fine for
two children. But if three want to talk,
each needs two walkie talkies — one for
each of the others, and so on.
By using a central hub to distribute
the particles to each pair as demanded,
Dr Joshi and his colleagues have got
round this. In a paper in the journal
Science Advances they claim that the re-
sulting system could provide a model
for a truly scalable quantum network.
Dr Joshi said that when it does it will
not just be good news for spies, but for
anyone who wants to keep their data
safe in the long-term.Reasons for solace
Quantum computers Hold promise
for drug design, more efficient
routing of goods and vehicles.Quantum navigation Supercooled
atoms could allow vehicles to
calculate their position precisely.Quantum surveying The movement
of a single atom can tell you not
only where you are but also what is
beneath you. Scientists have
developed devices that can spot, for
instance, underground pipes.patrick kidd
TMS
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TV pair broke
prince’s trust
Ant and Dec, the pushmi-pullyu of
family television, were awarded
OBEs in 2016 but had hoped to
make off with a bit more the first
time they visited Buckingham
Palace. In their new book, Once
Upon a Tyne, Ant (the one who
always stands on the left) recalls
going to a Prince’s Trust dinner
and hoping to snare a souvenir.
“What struck us was that there
wasn’t that much to nick, I mean
liberate,” he said. Not even a corgi.
All he saw was a Christmas tree on
which were hanging baubles in the
shape of crowns. Sidling up, Ant
took one off. “I’d had it in my hand
for 2.6 seconds,” he said, “when a
footman appeared behind me and
delicately but firmly whispered in
my ear: ‘Don’t even think about it.’”cometh the hour...
Woman’s Hour is looking for two
new presenters after Jane Garvey
announced on air that she was
following Dame Jenni Murray off
the programme. “Thanks for all
the comments,” she tweeted,
“especially the one that said I was
too opinionated and a man should
take over.” Don’t joke: gossip in
Broadcasting House is it will go to
Amol Rajan since it’s about the
only Radio 4 show he hasn’t done.The writer and socialite Taki
Theodoracopulos devotes his latest
Spectator column to a social
club he belongs to called
Pugs, whose treasurer is
Bob Geldof. A suitable
role for someone who
Taki suggests has
short arms and deep
pockets. “His idea
of an unnatural
act,” he says, “is to
reach for the bill.”mogg’s muddle
Jacob Rees-Mogg
appears to bemuddling his Tory grandees. “It is,
as Disraeli said, the job of the
Opposition to oppose,” the Mogg
told MPs, though I think he meant
Randolph Churchill. Labour’s
Chris Bryant, more surefooted in
his Dizziness, heckled back that
the Victorian prime minister had
also said that “a Conservative
government is an organised
hypocrisy”. This stung. “Not
everything Disraeli said needs to
be quoted,” the Mogg replied.
Only the things he didn’t say.Amid the debate about the greatest
prime minister we never had, which
began with a Times Radio poll and
continued in Daniel Finkelstein’s
column and the letters page, the
words of Tacitus seem apt. The
historian said the Emperor Galba
was “omnium consensu capax
imperii nisi imperasset” or that
everyone agreed he was up to ruling
if only he hadn’t done it. There’s a
few PMs that can be said about.dying for a sequel
As we near the 40th anniversary
of Flash Gordon, Brian Blessed is
itching for a sequel to the camp
space opera. “They must!” roars
Blessed, who played the shouty
leader of the Hawkmen, in Empire
magazine. “Me and Sam [Jones,
the eponymous beefcake] have
talked about it. I could be in an
ice-cave and he has to rescue me.
Set on Mars!” If Hollywood bites,
they must do it without Mike
Hodges, the original director. “Oh,
I hope they don’t,” he said. “They
did a dreadful remake of Get
Carter [his 1971 thriller]. I think it
stands alone.” His view was fixed
in 1980. Blessed, left, recalls the
actor Peter Wyngarde
pleading for his
character not to die
in case there was a
sequel. “Well you
do bloody die,”
Hodges replied —
and had Wyngarde
impaled on spikes
just to make sure.