2021 challenge 1

[cipher-challenge.git] / 2020 / plaintext.6a.txt

our london akela groups have been scouting for clues in areas with a large german population using
the cover of good turn day to visit a number of house sandflats known to be occupied by foreign
residents in most cases there was nothing to report which is not a real surprise as v ks group had
already vetted alot of them and found nothing to report the breakthrough came when one of the land
ladies mentioned that she was sad to see her previous resident leave so suddenly but glad that they
had be enable to recommend such a nice replacement for the flat i might have missed the importance
of this but we heard the same story at three different addresses in the east end of london all with
the same departure date and that coincided with the original arrival of the spy c list touring group
from norfolk one of the land ladies had somewhat fortuitously kept a record of the comings and
goings of her residents and was able to describe visitors to the departed tenant there had been an
increase in the number over the three weeks leading up to their departure and that date coincided
with the arrival of the spy c list touring group in the uk i circulated descriptions of the departed
tenants to our agents at the port authorities and they were able to confirm that a group matching
the description had left the country the day after the spy c list group arrived at kings cross our
agents and akela groups in essex and kent were asked to report on the spy c list groups in their
neighbourhoods and both teams sent me a list of the touring parties reconciling them against the
party of twenty that set off from lincoln we have lost another five along the way luckily the akela
group in essex had been watching for the departure from the east end and so we know that the full
twenty set off along the thames in two groups often with eight arriving in swale and seven at ca new
don the acrostic in the last telegram we intercepted spelled out the message at target rdf and iran
that past my air ministry contacts who at last agreed to brief me on their concerns rdf stands for
radio direction and finding i questioned this thinking it was an error and that they meant radio
direction finding the navigation system we use but apparently this is something new from the boffins
on the tizard committee they call it chain home and it refers to a new aeroplane detection system
that uses reflection of radiowaves to range find as well as indicate bearing from air threats they
have been experimenting with this for a while and are now building out a series of masts to give
frontline warning of air attacks the first few stations are being built in norfolk lincoln and essex
to provide a ring of defence around london and it looks like our spy c list friends are hunting for
information about this technology it is not clear if they know what it is but it is certain that we
have to stop them finding out i am also not sure what the missing party members are doing it cant be
just more spying as their cover with the touring parties allowed them as much access as they were
likely to get so something else is up i am hoping that the attached intercept will give usa clue we
analysed the encrypted telegram and found that it uses a classic adfg vx cipher it uses the same
keyword for the transposition stage of the cipher as i have used for this vi genere cipher and
knowing that it should be reasonably straightforward to crack their message but you will have to
check the details for yourself as i have to go harry has asked me to travel to caistor to setup a
command post at the rdf tower in case we need to act quickly if we can crack this one and workout
what is going on then i hope we can mount a counter to the spy c list operation before it succeeds
pearl