Thanks for this - I got some by myself, but was grateful for some help with others! I was disappointed though that this wasn't a video of the three of you together solving this live!
The Enigma machine is symmetric, which means that enciphering and deciphering is the same. So with the same settings, if you type in "abcd" you get "yudy", and if you type in "yudu" you get "abcd". Since it also never encrypts a letter back to itself, this was one of the main flaws in the design that makes the Enigma fairly simple to crack. "Simple", if you have an enigma so you know how the rotors are constructed, and enough computing power to simulate a few douzen or about 1000 enigma machines at once. I could go on about this for hours, probably.
Also, the enigma did not group characters, it was just that five letter groups are a good size for telegraphing random strings and had been used for quite some time before (and after).
Nice to see GCHQ’s CyberChef used to implement the Enigma Machine. CyberChef is a fantastic tool and very useful for all sorts of data manipulation tasks. Well worth a bookmark if you work in IT.
I thoroughly enjoyed this video. I had attempted the puzzles and I believe I managed to solve 5 of them, but became thoroughly stuck on the rest. Bravo to the CTC team for their brilliant solve!👏👏
My logical path for the six number sequence puzzle: The 5 (from the bank notes) can't be used, as regardless of which trio (which must sum to 25) it is in, the 20 can't go with it as that would sum to 25 before counting a third number, and 10 cannot go with it, as that would require a second 10 in the trio to make 25, repeating a number. (Now to show they cant be in opposite trios) The big number can't go with the 5 since a 10 needs to go in the other trio, meaning (with 10,7,8) the big number would need to be bigger than 18 and smaller than 20 (for the 25 sum to work), and 1,5,19 doesn't work since along with the 7, that's 4 primes. The big number can't go in the opposite trio from 5 as the other 2 numbers in the 5's trio must sum to 20, meaning the big number would have to be greater than 20, leaving nowhere to place a second bank note number. Once the 5 was painstakingly eliminated (meaning 10 and 20 were definitely in) it was obvious 20 would be the big number so the 10 needed to go with numbers
With the combinations 10/7/8 and 1/5/19, there are only three primes (7, 5, and 19). 10 and 8 are composite, and 1 is neither prime nor composite. This combination can be eliminated for a different reason, though: In order for the largest prime (19) to be placed in last position, you would need 1 and 5 to be placed in positions 2 and 4 in some order. But position 3 is meant to be the smallest number of the group, but 1 is already reserved for either position 2 or 4, so that fails.
@@psiphiorg Of course! How could I forget 1 isn't prime! I think when doing the puzzle I had already worked out 19 couldn't go in the puzzle by trial and error, but when writing up the logic path I needed to rule it out, and obviously I didn't think about it hard enough! Thanks for the correction :)
[spoilers] That was great fun! I ended up having to backsolve puzzle 7 because I was waaaay overcomplicating it XD when they use words like "bequeathed" I was looking for some sort of pangram or something. IMO that puzzle was too far along in the hunt for its relative difficulty. Glad to know I wasn't the only one momentarily thrown off by the seeming -ED in Morse for puzzle 2. For puzzle 10, I was very confused for a while; I knew Mjolnir as Thor's hammer from Norse mythology, and thought that must be the answer (what else would have that letter pattern??), but I couldn't get the M from Latifah. Finally, I just googled Fjolnir and found that it was, in fact, a Norse king! Funnily enough, it was FATHERING->FARTHING that clued me in to the final extraction step; it's not a particularly difficult anagram and FATHERING is just such a weird word.
For Puzzle 10, having worked out the correct positions of the chess pieces, I also got FJOLNIR by putting the letters of the answers to the questions into the coloured squares horizontally, but I hadn't recognised this as a word, just some random characters. Having put the letters to the answers to the questions going down vertically, I came up with the letters TIOUCNA which I rearranged to get the word CAUTION. With that incorrect answer to one of the puzzles, I would have never been able to solve the overall puzzle, but I am pleased that I managed to correctly solve 5 of the puzzles, including puzzle 11 (the binary one).
I am amazed at how Mark and Simon's team were able to solve the final puzzle, but I also see its complexity as a serious weakness of the overall puzzle hunt. That puzzle 12 is orders of magnitude harder than any of the other puzzles which came before it -- very imbalanced. I would have given up on puzzle 12, not expecting the solve path to be so complicated based on what had come previously. But, again, kudos to Mark, Simon, and Neil for being able to find the solution. Very impressive.
Had to stop at nº5. Family comes first. Now to resume before watching the video. So far it has been at about LMG 3 star. Hope it continues to be that easy! -- (Edit) Nope. Gets harder and harder. Had to watch the video in the end. Great puzzle.
Well of course the beginning part of the binary thing is random, that part is the year. If you're expecting people to Google for the exact dates of events you're limited to what years you can use, because the chances of there being an exact date on something diminish immensely as you go back in time. They figured out which month and year they needed to make the art work and then back solved for dates that fit it.
I got puzzle 8 pretty quick by trying to prove whether you need a five. If you use ten and twenty, that leaves the other four numbers to sum to twenty. That makes it obvious that twenty is the biggest number, and therefore you need three primes all of which must be less than ten and not five. There are only three such primes, making it trivial to find the last unknown number, eight. After that, all that's left is to determine the order and check that it works.
Solved problems 1 to 7 (with help from Google ;) ). For problem 8, I was trying to get the letters from the full title of his paper, namely, "On Computable Numbers, with an Application to the Entscheidungsproblem", which didn't work! Didn't even know where to start in problem 9. Solved problem 10, but dismissed the answer as a none-word. Extracted the dates for problem 11, but didn't think of converting to binary. An interesting array of puzzles.
I don’t know if anyone has spotted this, but the answer the puzzle one Eugenia is a welsh word and when it is translated into English you get the translation eugenics.
"Plug hat?" Never heard the term. Looking it up… no wonder, it's a generic term for a stiff hat with a narrow brim. Nonsense. We call top hats "top hats."
I fell down on this one as HIgh Hat was the one I went with, as in Puttin' on the Ritz. I had to guess the answer to that puzzle but it is my grand daughter's name!
@@maverickstclare3756 first, and probably last. I've never heard of it called a "plug hat" in any context from any source, either in person over the past 20 years, or in media from the past 60 at least. It's a tophat. Well no, that's a lie. I have seen one instance of it being called a plug hat, and that was in a movie set in the early 1900s.
I happen to be in timezone GMT+8:00 so it’s Friday here when i received Thursday’s edition of CTC this morning, and now I received this earlier this evening. Lot’s of weird stuff.
The Norse name it sounded like you were saying to seem to be the name of Thor's hammer, but in the comments someone pointed out it started with an F whereas Thor's hammer I believe starts with an m...
@@charliee.7833 I read that in the comment, what my question was about was the name of Thor's hammer... I'm not sure of the spelling, but I believe it was almost the same with an m instead of an F at the beginning. Is this true?
It did indeed from 1817 to 1914. Weirdly, before that it had a nominal value of 22s 6d. My source is Chambers Dictionary, which I don't necessarily trust, but it had clearly been used in the challenge's creation. Mark
Puzzles are nice and all, but I still dislike when the GCHQ tries to interact with the public. Snowden, and the fairly recent snoopers charter are still fresh in my mind.
At 25:00, the sign-in book is full of top secret people. So the fourth must be Maxwell Smart, agent 86. You can see he has given his first name as 86.
That's smart.
Thanks for this - I got some by myself, but was grateful for some help with others! I was disappointed though that this wasn't a video of the three of you together solving this live!
The Enigma machine is symmetric, which means that enciphering and deciphering is the same.
So with the same settings, if you type in "abcd" you get "yudy", and if you type in "yudu" you get "abcd".
Since it also never encrypts a letter back to itself, this was one of the main flaws in the design that makes the Enigma fairly simple to crack. "Simple", if you have an enigma so you know how the rotors are constructed, and enough computing power to simulate a few douzen or about 1000 enigma machines at once.
I could go on about this for hours, probably.
Also, the enigma did not group characters, it was just that five letter groups are a good size for telegraphing random strings and had been used for quite some time before (and after).
A fitting tribute to a brilliant mathematician whose only crime was being made redundant after the war was decided. Well done to GCHQ.
Even cleverer than solving this puzzle is ... setting it! Wow! Hats off for the setter(s).
GC & CS = Government Code and Cypher School, although somebody at BP suggested it was "Golf Club and Chess Society"... (before they became busy!)
Nice to see GCHQ’s CyberChef used to implement the Enigma Machine. CyberChef is a fantastic tool and very useful for all sorts of data manipulation tasks. Well worth a bookmark if you work in IT.
Missed opportunity to call it "Turing Test"
Turing called it "The Imitation Game"
SEO would not be strong if they chose that title
To coin a phrase, "Sterling Job"
Unfamiliar to the idiom, I thought it was an episode title of the series Leverage.
I thoroughly enjoyed this video.
I had attempted the puzzles and I believe I managed to solve 5 of them, but became thoroughly stuck on the rest.
Bravo to the CTC team for their brilliant solve!👏👏
My logical path for the six number sequence puzzle: The 5 (from the bank notes) can't be used, as regardless of which trio (which must sum to 25) it is in, the 20 can't go with it as that would sum to 25 before counting a third number, and 10 cannot go with it, as that would require a second 10 in the trio to make 25, repeating a number. (Now to show they cant be in opposite trios) The big number can't go with the 5 since a 10 needs to go in the other trio, meaning (with 10,7,8) the big number would need to be bigger than 18 and smaller than 20 (for the 25 sum to work), and 1,5,19 doesn't work since along with the 7, that's 4 primes. The big number can't go in the opposite trio from 5 as the other 2 numbers in the 5's trio must sum to 20, meaning the big number would have to be greater than 20, leaving nowhere to place a second bank note number.
Once the 5 was painstakingly eliminated (meaning 10 and 20 were definitely in) it was obvious 20 would be the big number so the 10 needed to go with numbers
With the combinations 10/7/8 and 1/5/19, there are only three primes (7, 5, and 19). 10 and 8 are composite, and 1 is neither prime nor composite. This combination can be eliminated for a different reason, though: In order for the largest prime (19) to be placed in last position, you would need 1 and 5 to be placed in positions 2 and 4 in some order. But position 3 is meant to be the smallest number of the group, but 1 is already reserved for either position 2 or 4, so that fails.
@@psiphiorg Of course! How could I forget 1 isn't prime! I think when doing the puzzle I had already worked out 19 couldn't go in the puzzle by trial and error, but when writing up the logic path I needed to rule it out, and obviously I didn't think about it hard enough! Thanks for the correction :)
[spoilers] That was great fun! I ended up having to backsolve puzzle 7 because I was waaaay overcomplicating it XD when they use words like "bequeathed" I was looking for some sort of pangram or something. IMO that puzzle was too far along in the hunt for its relative difficulty. Glad to know I wasn't the only one momentarily thrown off by the seeming -ED in Morse for puzzle 2. For puzzle 10, I was very confused for a while; I knew Mjolnir as Thor's hammer from Norse mythology, and thought that must be the answer (what else would have that letter pattern??), but I couldn't get the M from Latifah. Finally, I just googled Fjolnir and found that it was, in fact, a Norse king! Funnily enough, it was FATHERING->FARTHING that clued me in to the final extraction step; it's not a particularly difficult anagram and FATHERING is just such a weird word.
For Puzzle 10, having worked out the correct positions of the chess pieces, I also got FJOLNIR by putting the letters of the answers to the questions into the coloured squares horizontally, but I hadn't recognised this as a word, just some random characters. Having put the letters to the answers to the questions going down vertically, I came up with the letters TIOUCNA which I rearranged to get the word CAUTION. With that incorrect answer to one of the puzzles, I would have never been able to solve the overall puzzle, but I am pleased that I managed to correctly solve 5 of the puzzles, including puzzle 11 (the binary one).
The irony is that this is a reverse Turing Test, and by solving it you’ve proven that you are in fact machines. We’re on to you!
I am amazed at how Mark and Simon's team were able to solve the final puzzle, but I also see its complexity as a serious weakness of the overall puzzle hunt. That puzzle 12 is orders of magnitude harder than any of the other puzzles which came before it -- very imbalanced. I would have given up on puzzle 12, not expecting the solve path to be so complicated based on what had come previously. But, again, kudos to Mark, Simon, and Neil for being able to find the solution. Very impressive.
Another phenomenal video? Yes, please.
In puzzle 11, the seemingly random bits of black and white could be a homage to the dalmatian coat Cruella was trying to make.
Thoroughly enjoyable!!
Had to stop at nº5. Family comes first. Now to resume before watching the video. So far it has been at about LMG 3 star. Hope it continues to be that easy! -- (Edit) Nope. Gets harder and harder. Had to watch the video in the end. Great puzzle.
Well of course the beginning part of the binary thing is random, that part is the year. If you're expecting people to Google for the exact dates of events you're limited to what years you can use, because the chances of there being an exact date on something diminish immensely as you go back in time. They figured out which month and year they needed to make the art work and then back solved for dates that fit it.
Fjolnir is often referred to as a name used by Odin. So "Who holds the crown" alludes to the fact Odin was the king of asgard :)
Nice job - I enjoyed watching this c:
I got puzzle 8 pretty quick by trying to prove whether you need a five. If you use ten and twenty, that leaves the other four numbers to sum to twenty. That makes it obvious that twenty is the biggest number, and therefore you need three primes all of which must be less than ten and not five. There are only three such primes, making it trivial to find the last unknown number, eight. After that, all that's left is to determine the order and check that it works.
Solved problems 1 to 7 (with help from Google ;) ). For problem 8, I was trying to get the letters from the full title of his paper, namely, "On Computable Numbers, with an Application to the Entscheidungsproblem", which didn't work! Didn't even know where to start in problem 9. Solved problem 10, but dismissed the answer as a none-word. Extracted the dates for problem 11, but didn't think of converting to binary.
An interesting array of puzzles.
I don’t know if anyone has spotted this, but the answer the puzzle one Eugenia is a welsh word and when it is translated into English you get the translation eugenics.
"Plug hat?" Never heard the term. Looking it up… no wonder, it's a generic term for a stiff hat with a narrow brim. Nonsense. We call top hats "top hats."
I fell down on this one as HIgh Hat was the one I went with, as in Puttin' on the Ritz. I had to guess the answer to that puzzle but it is my grand daughter's name!
16:40 That's curious, it's almost as if those lines rhymed.
I think in an episode of Morse or Lewis GC&CS was codedly referred to as Golf Cheese and Chess Society as part of the story line.
Hey what a suprise! And it's my leave day.
You should try and do the Oddpawn challenge one day...you're so clever. Good job
I really loved it
Are there collectible un-circulated versions of the note. The UK equivalent of usmint.gov?
"The american term for tophat is-" It's tophat. We still call it a tophat. Wherever you got that information of "plug hat" or whatever, it's wrong.
Yup. That one held me up f.o.r.e.v.e.r! Luckily, the flower can be solved without it.
Merriam-Webster who note the first use of such was in 1860
@@maverickstclare3756 first, and probably last. I've never heard of it called a "plug hat" in any context from any source, either in person over the past 20 years, or in media from the past 60 at least. It's a tophat.
Well no, that's a lie. I have seen one instance of it being called a plug hat, and that was in a movie set in the early 1900s.
Superb.
hat was pretty cool!
Excellent
Are we on the wrong am-pm or is this an amazing bonus video? 😄
Mark announced this bonus video on his video yesterday.
Someone turned the clocks back too far?
I happen to be in timezone GMT+8:00 so it’s Friday here when i received Thursday’s edition of CTC this morning, and now I received this earlier this evening. Lot’s of weird stuff.
The UK switched it's day-night cycle as part of Brexit. It's just now going into effect.
The Norse name it sounded like you were saying to seem to be the name of Thor's hammer, but in the comments someone pointed out it started with an F whereas Thor's hammer I believe starts with an m...
fjolnir is a figure in norse mythology
@@charliee.7833 I read that in the comment, what my question was about was the name of Thor's hammer... I'm not sure of the spelling, but I believe it was almost the same with an m instead of an F at the beginning. Is this true?
Yes, Thor's hammer is Mjölnir, according to Wikipedia, Mark
That is a beautiful rendition of the theme tune Simon!
How hard was it to say "compound words" instead of "agglutinative language"?
Pity they didn't offer free samples for successful submissions ;)
What does the G stand for? The G stands for great game.
Or Divya G.
And his contribution to Corporate logos... specifically Apple Computer
So if you are the first to submit an correct answer to GCHQ do you get a job interview?
I managed to get 10 out of the 11 clues.
But I had no inkling at all that you had to make coins out of the clues.
Just ... wow ...
Didn't anyone else spot the 'deliberate mistake'? The sovereign had a nominal value of one pound sterling, i.e 20 shillings, not 22s 6d
It did indeed from 1817 to 1914. Weirdly, before that it had a nominal value of 22s 6d. My source is Chambers Dictionary, which I don't necessarily trust, but it had clearly been used in the challenge's creation. Mark
Here's a comment for the algorithm
🤩
I didn't get many of these :|
Puzzles are nice and all, but I still dislike when the GCHQ tries to interact with the public.
Snowden, and the fairly recent snoopers charter are still fresh in my mind.
Putting Simon on the thumbnail is click baiting.
The audio could be much better.
it's better than the audio on your channel
Seemed plenty good enough to me
The incredible brain ecologically marry because kohlrabi literally spoil circa a hilarious loss. rich, jittery avenue
Who TF is this guy?
Very important figure who was mainly forgotten due to his homosexuality (he was killed for it)