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December 28, 2005
Prizegiving
There will be a prizegiving at Bletchley Park on the afternoon of Friday 31st March. As always tickets are very limited, but if you would like to come email us and we will put your name on the list for the ticket lottery. The afternoon will include a tour of the museum.
Hope you are having a good holiday,
Posted by Harry at December 28, 2005 09:30 AM
Comments
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"6DYIGP8Z" is "COMRADES" - yes, also, if you remember, there was a long range message which had the main part of the message twice, if you take the length of 6DYIGP8Z... to the end and go that far back from 6DYIGP8Z, you'll find the beginning of the first repetition, which is also comrades, and that gives you the length of the header (which includes the crib) so you can try and guess the position of the crib
Posted by: Frank Hamand at January 4, 2006 04:57 PM
Will anymore information be forthcoming before the end of the challenge? "6DYIGP8Z" is "COMRADES"?
Posted by: OcelotIIX at January 2, 2006 08:04 PM
Harry could we have some more settings? Which way round the rotors are and the direction of the wiring mazes for example.
Thanks
Posted by: Need more settings! at January 2, 2006 11:02 AM
Na ignore my last comment I think I have found the problem.
Thanks
Steve
Posted by: Steven Lamerton at January 2, 2006 09:46 AM
Steven
You need to allow for the two possible permutations of the direction that the rotors move,
eg. rotor 1 towards, rotor 2 away
or rotor 2 away, rotor 2 towards
Posted by: Jonathan at January 2, 2006 08:55 AM
Well done Kati!
Posted by: Jess at January 2, 2006 12:12 AM
Yesss! Finally! Solved (with three days left, phew!).
My problem was that I had the rotors rotating the wrong way...if that helps any!
Kati
Posted by: Katriel Cohn-Gordon at January 2, 2006 12:04 AM
HELP!!
I thought that I was doing so well. After programmimg (almost) soldily since Friday I have come up with a program that brute forced all of the settings, that is:
-Which way the rotors are inserted
-Which way the wiring maze is inserted
-The start point of the rotors and reflector
-When the second rotor trips to move to first rotor
It can also reflect the reflector and I have still had no luck. Can anyone help as it is starting to worry me that I have only two full days to go as I am back at school on Wednesday and the challenge finishes on Thursday. Argh.
Thanks
Steven
Posted by: Steven Lamerton at January 1, 2006 08:55 PM
Happy New year!
Posted by: Josh at January 1, 2006 10:20 AM
I can't computer program and have made the pringle machine. It still seems very difficult and that i will have to go through a lot of different combinations. Is there any way to reduce these (apart from rotor 1 being one of the weather report numbers). Has anyone done it so far using the pringle machine and not a computer? Also is the picture of the reflector correct in the initial notes or the pringle notes. Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaah.
SOMEBODY PLEASE HELP ME.
Posted by: Miol at December 31, 2005 09:35 AM
if it can hit in one of 36 places on the 1st and 2nd rotor, then surely thats a hell of a lot of possiblities. how do i try them all? am i even meant to try them all or is there an easy way i'm not seeing?
[The operator got careless and used one of the numbers from the weather report as the rotor one setting! Harry]
Posted by: lara at December 29, 2005 06:19 PM
I can try.
You can think of the encryption / decryption as a current going through the wires in a machine. You press one letter and that letter is changed by the punchcard, goes through the wires inside the 2 rotors and at the end through a reflector which just sends the signal back through the 2 rotors by a different route and out of the punchcard (plugboard). Inside the rotors are wires which connect to different points on the next rotor.
Posted by: злейшая обезьяна с 3 глазами at December 29, 2005 04:26 PM
Iara,
The best thing to do is make the Pringle Machine.
Harry's plans are very clear...you may need to resize the plans of the punchcard, rotors and reflector to get them to fit properly round the pringle tube, but it is not too bad.
Image the two rotors as spinning wheels on a combined spindle. Hold the axle in front of you. Spin the wheel on the right AWAY from you. A complete turn of this right wheel is a complete 36 letter revolution i.e. you will see every character directly in front of your eyes just once.
Now imagine a mark on the tyre. Everytime this mark is in a certain position (e.g. perhaps at the top of the wheel), the second rotor (the one on the left) turns a little bit (one letter) but TOWARDS you.
A character is typed on the keyboard. It goes through the fixed punchcard setup...just think of this as a maze that swaps a character for its partner character as define by the punchcard...and hits the first rotor/wheel (the one on the right as you are looking). Depending on where this wheel is in its rotation, the character will hit the rotor in one of 36 places. It will travel through this wheel and emerge on the other side...as defined by the wiring setup given to us by Harry.
When it leaves the first rotor hit will hit the second rotor. Again it will hit this left rotor in one of 36 places (depending on how the machine was initally setup).
It will move through the rotor, following the wiring setup, leaving on the other side.
Here it will hit the refector. The reflector maps each of the 36 characters to a partner character. The reflector can also be in one of 36 places.
The reflector swaps the character with its partner and send it back throught the machine on its return journey...first through the left rotor, then through the right rotor and finally through the punchcard. It emerges as a new character.
Now, this new, encoded character it written down. The first rotor moves one step (away from you, as you hold the axle), and IF the mark on this rotor is in its predefined position, the left rotor moves one step towards you. So 35 times out of 36 the right rotor moves one step after the character has been encoded. THe 36th time, both rotor turn (one towards you, the other away from you).
The clever thing about all of this is that if you can get the machine back to its initial setup (i.e. the rotors and the reflector are in the orginal start positions relative to the punchcard) and then start typing in the encoded text, every character retraces its path through the punchcard, rotors and reflector, emerging as the original plaintext.
I hope this helps. Make the Pringle Machine even if you are still not sure. If you can get a friend to make an identical Pringle machine, and you both agree on the inital positions of the moving bits, then you have a pretty secure way of sending coded messages to each other.
Eleven1
thr reflector
Posted by: eleven1 at December 29, 2005 03:55 PM
harry, you're probably sick and tired of this question now, but how on earth do rotors and reflectors work? please tell me. i really want to crack this.
[Anyone want to try explaining this? Harry]
Posted by: lara at December 29, 2005 12:46 PM
Will the overall winners automatically get tickets to the prizegiving? It would be weird if they couldn't go because they hadn't put their names down :)
[The winners of the IBM, GCHQ and Trinity prizes will be invited to the event. Harry]
Posted by: Simon at December 28, 2005 09:05 PM
How many solvers yet? (You're probably getting sick and tired of this question by now ;)).
How's everyone doing?
Kati
[17 so far! Harry]
Posted by: Katriel Cohn-Gordon at December 28, 2005 10:00 AM