Competitor Ciphers & Challenges

[Puzzling_Pelican]

A place to post all the ciphers, cryptography puzzles and challenges made by competitors (and alumni!) for each other, all in one place throughout this year.
If you have put together any cipher-related problems (whether using an existing cipher or one you came up with yourself) that you would like to see other competitors try to break, post them in this thread.

A few quick rules, just to help out the moderation team:

• Give each challenge a title. If you can’t think of one, use “username-<num>”. This makes it easier to refer back to individual challenges.
• Post both the challenge and its solution. When posting a challenge, split it into 2 parts: the challenge (what you want the forum to see) and the solution (so Harry, Jodie or the Elves can check how difficult the challenge is before releasing it). These should be 2 separate posts clearly labelled “<title>” and “<title> – Solution”. Only the challenge will be released initially, the solution will remain unpublished.
• Set a release date for the solution (optional). If you want the solution to be released after a particular date, write “Release date: dd/mm/yyyy” immediately after the title line in the solution post. The moderation team should be able to schedule it to be automatically published.
• Submit a proof when solving a challenge. To prove that you have solved someone’s challenge without simply posting the plaintext, [EDIT BY HARRY: the original post said “run the Python script below with your username and the plaintext. This generates a cryptographic hash which proves you know the correct plaintext without revealing it. Post this hash as your solution.” We prefer not to post user generated code here on the forum, but will post our own Puzzle Proof app on the cipher tools page as soon as we can. In the meantime enjoy the puzzles below!]
• Reply to the original challenge once solved. Once you have solved someone’s challenge, reply to their original post with the hash you generated. The creator can verify your solution by running the same script with your username and their intended plaintext and checking that the hashes match.

[EDIT by HARRY: I hope you don’t mind, but I have removed the clever script you posted here on the basis that we prefer to be in control of things like that. Instead we will post our own “Puzzle proof” app on the cipher tools page soon.]

Good luck and happy puzzle making!
Puzzling Pelican

• This topic was modified 1 month ago by Harry. Reason: To remove python script and explain why!

[Puzzling_Pelican]

Upsidedown – Bombe

To start this thread off, I wanted to re-highlight a challenge made by upsidedown last year, designed around the Turing–Welchman Bombe.
All credit goes to upsidedown for this challenge, thank you!
This challenge was originally posted in Harry’s Christmas Miscellany. However, very few people have solved it, and it appears no solutions were posted on the forums last year (mine didn’t get through the moderation pipeline before the forums closed). I think that such a well put together challenge deserves more attention from competitors.

Alumni, this will be fun for you too.

https://www.cipherchallenge.org/wp-content/uploads/2025/12/CC2025-the-bombe.pdf
https://www.cipherchallenge.org/wp-content/uploads/2025/12/CC2025-the-bombe.pdf

[Puzzling_Pelican]

My solutions || Puzzling_Pelican (upsidedown’s proof method):
4. 3e6dc4df4a31c55f8967cd5754a61472
5. a107333c5783fa12ef299ea0c021df00
6. 99bd5cad526338b5c95d56acef18ae11
7. ???? Please send clues (rot 13’d), I have been waiting half a year with 26 intermediate candidates and no progress on the 2nd part

P.S. “Instead we will post our own “Puzzle proof” app on the cipher tools page soon”: That would be amazing, thank you!

[upsidedown]

I agree with the plugboard pairings in your solutions, but I was expecting different Bombe indicators for 5 & 6. Not sure if it’s my mistake or yours, and I don’t have time at the moment to work it out. If you add AAR to your indicator for 5, and add ZZO to your indicator for 6, you get the values I was expecting. Possibly something to do with working backwards to find indicators at the start of the message? Or a problem with the step function?

7 is possible to solve, but it is rather difficult without knowing what the second cipher is. I’ve prepared a few hints (all encrypted with the same settings I used for upsidedown-2025-6). The plaintext comes from the same source as the other plaintexts.

upsidedown-2025-7 Hint 1: PSDA DCST VUHZ BPRU PKOG AFJH YVHE SCZE WVNI BTLF HLCG WAGZ PNGA TLCB JGMQ TMUN HWXI ZWWU XHEQ YZZN YWFE LXEW UWUY RQTF OUUZ NWAU TCMQ NPUI UMSL GW

• This reply was modified 1 month ago by Harry.

[Puzzling_Pelican]

Thank you for the clue. As for the indicator mismatch, I think it came from me forgetting to combine rings and indicators in my proofs (subtracting my rings is the same as adding those differences).

[Puzzling_Pelican]

I would argue that there is a 3rd cipher.
The clue helped a lot, I do not think I would have solved it without.
Thank you for this challenge, I truly enjoyed it.
Puzzling_Pelican || Plaintext without any spaces or punctuation:
fa1361a0e38d9abf37157875dc082689

[upsidedown]

Excellent, well done. Glad you enjoyed it 🙂

Yes, a third cipher is a reasonable interpretation; the 2nd and 3rd stages share a key and are ultimately quite similar, which is why I have grouped them.

[Puzzling_Pelican]

@upsidedown Just for testing the proof, here is part 7 (no spaces but all symbols, note the en-dash in the title)
NCC-PROOF-v1:b1cf087304633f345818d95c07e5923bafd28a5b3fd4eb77dc5146b1e60a15b4

[upsidedown]

@Puzzling_Pelican Yep, I can reproduce your proof. For avoidance of doubt the challenge identifier used was “Upsidedown – Bombe”

Harry: further to my other comments, maybe replacing confusable characters like em-dash & en-dash to a hyphen would be helpful? Also curly quotes to straight quotes.

[upsidedown]

@Puzzling_Pelican thanks for the kind words.

I’m interested in making my Bombe guide accessible to a wide audience, so readers: please tell me if you find any errors, or more importantly anything that’s confusing or unclear. Should you have any questions, I’m very happy to help. And I can provide hints for the included challenges on request.

If anyone is interested in learning how Alan Turing and Gordon Welchman cracked Enigma, and has some familiarity with a programming language, give my guide a go!

I have an updated version that fixes an error (in the last paragraph of page 23, “n – 1” should say “n – 2”) and a few typos which may be published soon on the resources page.

[Robb27]

@Puzzling_Pelican & @upsidedown.
Hi both! I can’t believe I missed this last year. I was busy with work, so if it was within the Christmas Miscellany, that might be the reason. I’ve downloaded the pdf and will enjoy working though it.

[upsidedown]

@Robb27 Hi, nice to see you again 🙂 Hope you like it!

[Robb27]

I have completed up to and including Scrambler … nice to see I get a mention [Edited by Harry to avoid data leak ;-)!] 😉

• This reply was modified 1 month ago by Harry.

[Robb27]

@upsidedown Challenge: upsidedown-2025-4
To check I am good to this point I have the following for challenge upsidedown-2025-4

Your MD5 method:
Using Robb27
Scrambler at the offset mentioned and resulting Plugboard pairs in the format described per your pdf
1a7f2b4cae1a3eca6eb06c3f2d05c8b6

NCC SHA-256 method:
Using Robb27
Plugboard pairs entered to the “Puzzle answer” input as letter pairings in the same order as above separated by a space, no commas or double speech marks.
PROOFv1:581054d4e5ea9ef92df3499164bcc80e241ec56916cf0d579dc5dbbcb5cca3af

[Robb27]

@upsidedown Challenge: upsidedown-2025-5

I believe I have the right plugboard settings. I can generate the same MD5 hash that @Puzzling _Pelican posted a107333c5783fa12ef299ea0c021df00.

Using the NCC SHA-256 proof tool with just the plugboard settings I get “PROOFv1:e745a32b93ae1f697cfff1eb96a35f50ea271920099135125c8544f7906efdb4” which should allow you to verify.

I think the issue discussed with @Puzzling _Pelican regarding the indicators stems from the criteria “The middle rotor didn’t turn”. With this restriction the rings and indicators are not uniquely identifiable, each of the 17,756 different settings will generate the same correct plugboard output (at least that is what I am seeing). In the pdf instructions, you use the indicator as part of the MD5 hash, so it is not surprising that the plugboard can be correct, but the MD5 hash is wrong.

I guess for the next challenge, where the middle rotors turn, then this wont be an issue? I’ll soon find out!

[Robb27]

@upsidedown Challenge: upsidedown-2025-6

Again, I believe I have the right plugboard settings. I can generate the same MD5 hash that @Puzzling _Pelican posted 99bd5cad526338b5c95d56acef18ae11.

Using my username and the same indicator setting as P_P I get:
MD5 5b3f0810ad7dcc3d7eb9467f07cc53fd.
NCC SHA-256 PROOFv1:b742c9aff08d80f6f9595c9615b07e0a2154b6aebaa4a700a606478af26a75e5

I have a BOMBE setting returned from my program using the method you describe. If I use this, instead of the same setting as P_P, along with the plugboard, the MD5 I get is 75cc0728fad74469b8f7667316c1829a. Would this be what you were expecting? If not, I may have misunderstood the BOMBE instruction.

[upsidedown]

@Robb27 I agree with your proofs for upsidedown-2025-4 & 6, and the plugboard proof you posted for 5. For 75cc0728fad74469b8f7667316c1829a, what I was expecting was that value plus ZZA (so, first two indicator letters go back one letter).

I’m not sure I follow what you’re saying about rings. This shouldn’t affect the Bombe indicators (i.e. the indicators you’d see on the Bombe drums for the first letter in the message when the Bombe stops) because within the context of a Bombe run the rings are always assumed to be zero (and it doesn’t matter what the rings are because the middle rotor doesn’t turn).

I will see if I can figure out what’s going on here; it is looking like my mistake given that you and @Puzzling_Pelican reproduced identical indicators.

The code I run to get the indicators I expect for upsidedown-2025-5 is just:

menu = Menu("icanfeel...", "GSJSEDXBP...")
Bombe(menu, ("I", "II", "III"), "B").run()

and my Bombe implementation just prints what I call the “Bombe indicators” when it finds the stop. My Bombe.run() method looks roughly like this:

def run(self):
  for pos in range(26**3):
    grund = decode_grund(pos)

    if this is a valid stop:
      print("".join(alphabet[g] for g in grund))

def decode_grund(pos):
  return [pos // 676, (pos // 26) % 26, pos % 26]

# This function gets the scrambler permutation output when 'letter' is input
# at 'offset' in the menu/crib.
def scrambler(self, letter, offset):
  # Since we assume that no middle rotor turnover
  # occurs, the top two rotors should be kept the
  # same
  pos = 26 * (self.pos // 26) + (self.pos + offset) % 26
  return self.lookup.get(pos, letter)

Does this look roughly equivalent to what you’ve written? Particularly the ‘pos = 26 * (self.pos // 26) + (self.pos + offset) % 26’ line – that’s implementing the Bombe stepping which differs from regular stepping.

[Robb27]

@upsidedown
My output file for upsidedown-2025-5 looked a bit like this (actual values replaced to not give anything away)
rotor_order rings indicators effective plugboard_pairs
indicators
I-II-III AAA MMM MMM AB CD EF GH IJ JL
I-II-III AAB MMN MMM AB CD EF GH IJ JL
I-II-III AAC MMO MMM AB CD EF GH IJ JL
I-II-III AAD MMP MMM AB CD EF GH IJ JL etc

So my answer, the effective indicator + plugboard, was the same for every ring/indicator shifted by 1 letter, hence saying “17,756 different settings will generate the same correct plugboard output”

I will send @Harry my python and ask him to forward to you. We all see the path to coding a working solution differently.

[upsidedown]

@Robb27 Thanks, I’ll take a look if it comes through. I agree that there are 26^3=17,576 ring settings that will generate the same plugboard pairings (when the middle rotor doesn’t turn) – the value I’m looking for is the indicator when the rings are (0, 0, 0). These indicators should be [actual indicators] – [actual rings], and I can confirm that the indicators I get from the Bombe stop match this calculation applied to the real indicators & rings. In order to get a valid stop you must have the same monoalphabetic substitution as the true settings at each offset in the crib, so it seems to me that the only reason we could disagree on indicators is that our indicator -> scrambler substitution mapping differs.

[harry]

@Puzzling_Pelican and @upsidedown, if you email me at [email protected] I can send you a link to test our new puzzle proof tool as promised. Thank you, Harry

• This reply was modified 1 month ago by Harry.
• This reply was modified 1 month ago by Harry.

[harry]

As promised, we have built a puzzle proof tool so that your fellow competitors can establish that they solved one of your challenges without having to publish the proof. It can be found on the cipher tools page. It would be great if one of our alumni could write up a short explainer – we have a news item about this tomorrow, but I am sure you can do better than that. One of the neat features is that the calculations are all done in your browsers, so we don’t ever have to see or store your solutions!

Harry

[upsidedown]

upsidedown-2026-1: Puzzle Proof Puzzle?

In the recent news post, I included the following proof:

PROOFv1:e88c1923b4cf0a46f856a0afe9814b8051ebd392b0970b8a6f623728ddbc8dc2

To generate it, I used my forum name, the challenge id upsidedown-2026-1, and a two-word phrase. What was the phrase? Prove your solve using a proof of your own.

[Puzzling_Pelican]

PROOFv1:fc02f31306450088aa2d5cdd99a80a4aead3799cec9a2eaaab1aa11d6d4dda04

[upsidedown]

Yep, correct. Very quick as always 🙂

[PS_HoHoHoCCH]

pretty creative!!

PROOFv1:8720394a923f623a84a1dd36712c6f69a3ef0d1581ac23fa0df7ed95e506a2c5

[Robb27]

@upsidedown
I have the intermediate text, well it included the crib correctly and in the correct place. I understand Hint 1. Without saying too much, I have looked all the way to the start. With no standard ioc and a 27 (3^3) char alphabet (which is stated in your pdf) I can only think of one cipher and it spits out rubbish, unless my implementation of it is wrong… it has been known 😉

Could I have Hint 2 please.

[upsidedown]

Certainly. Hint 2 reveals what the 2nd stage cipher is, hopefully confirming what you already know: KQBJ ZCIN WXHZ KUYZ HU

Hint 3 reveals the modification I applied to it: VQEV OQHR DGSF HPFL HMZB WBBM WKPA VWNJ WNCU OFLM SLL

[madness]

@Robb27, could you show us the intermediate text that you have? Thanks/cheers/cnacu6o.

[Robb27]

Hi @madness,
As I mentioned I believe this is correct, it has the crib “SIAZZNXRFIKNKICVIQAQEHLPDSIEUAINFMIRFIHA” mentioned in the correct place.

YMUDE.EBQQIBOMGPD.EAMSIGZCJVYYGOTZHNSKHNUMVSIHPQJEZJQZNXRDYIPDSHAHQHLRMETGQJDUFICMESGGNXLUEAPQARICNDDRGGRDEXKSGNZPPQHCG.HJHMV.BNXMZCVEHMXVBOWAMZBQRDGKHNTOMDYEUOGZEJILDDVSIFSPIHHQELAADVUDFTNXMYHZNXQAREDBAFXYIDWSIMETGQJVSIINDBAGRDYTIM.HDXTSD.XDZZNXPDGIWAESIKHHKJDVSIAZZNXRFIKNKICVIQAQEHLPDSIEUAINFMIRFIHADWYMSGDTHOXVIREZRHKDREZRIOAGPETDFXAPHPRVWZJRHAGMSIIWEVOWZPDSGDMIXMTNGCNFWRSHYIUK.DLYGJNRDVTADCNKBELILBWJIXEBYYYGLWWFJLYRTHKDOHCZF.IGKRYDVCU.REKYDMRZUICYM.LCH.YQNGHHKMKEOTKZTMXUEHCXAZUPSZMRWEFXFX.YQKARQYQQMHOGPRFOEZJZIKOTIZROATATPJSHEMYTHAABTMAASYHRITXBNIMDICZGIOFKUMTHEQCOJXDNTJEDVYEYMSIFIIVHMHHPDQPQVRIAHBYQOLXHJHMVZHCNDETGQQREEMMTCEUMI.MDZBLEDQZNXPIGZAMIBKQMIFV.GEDVVSHAPIXDZPRXBZPDZENJIJGUDEYODZCRVETGRN.PREWAGGNUDXZLAADZUDSEZNGRNWVMVYHQKQBGFTZLMBD.QARIA.ECNZBRPQPQUWYRGZCJVTAIJCFGEYMGDRANYQQBDRDXWDDRHAGPIQDRFXWBBNGRQAETGPRICEEMQBJIDWTLBNKFDD.IDDVSGDTAPHDGGMZCOXCEAIMVVSIBROWSEBEJFTZREEECGGGOWENROWTSD.XFUNANZPDSHAREDNSRFEWSQHRIMGNJIRHQJRIWEOVEDPDUDINEMMSIBHOQEQMDRHFVZDRFWXLVIXBSGODGORWEVOWSW

[Robb27]

@upsidedown / @madness
I have the plaintext, albeit with a little junk in the middle, but the start and end are meaningful. I’m a bit busy this morning, so I’ll go back over my working when I have time later so see where I have introduced the error that causes the section in the middle to be wrong. I’ll post my proof hash when I am done.

@upsidedown This has been a great challenge. Many thanks for you time in writing the document and creating the challenges to progress the reader through the different elements of the Enigma machine. Thank you also for re-mentioning on the forum as I missed it last year.

[Puzzling_Pelican]

@Robb27
What happens if the middle rotor turns one earlier or one later? Only a few chars in the middle get broken, the rest looks correct.
I think I had around 20 valid intermediates all which had that same crib in the middle. One of the (hint the one you posted is not the one I used) will decrypt correctly. Given you have the start and end, you should just be able to repeat the same for all 20 and see which looks best.

@upsidedown
I would love to see how the cipher variant actually works later, I think I broke it differently than expected.

[Robb27]

@Puzzling_pelican Thanks, I have persevered! I now have a fully decrypted, sensible plain text. It was a slightly different Engima ring and indicator setting than those used to obtain my previous intermediate text. I now see that I get about 14 or so intermediates where the crib is correct. I had stopped my function too early when it found the first match. The intermediate decrypt function was working correctly.

Challenge: upsidedown-2025-7
PROOFv1:f24b76bbd41aad9594312318bb32fb57b4f6a2ee755ea40660447e1be87b2e5f

This is what I love about the NCC forum; positive, constructive assistance and encouragement which gives that extra lift or nudge to help you work things out.

[upsidedown]

@Robb27 Excellent, well done. Really pleased that you liked the guide/challenges 🙂

[ByteInBits]

BIB CHIPHER 1

The Horns have many interests in common desides music;
they have recently been stuying the subject of ciphers,
and often amuse themselves by leaving mysterious messages
for each other about domestic matters and so forth. Last
Monday Mr. Horn had to unravel this bit of obscurity
from an absent wife, before he ccould get at the contents
of a certain cupboard:

===================================================
Sevenths in sequence, each closing on the sixth.
Follow 5, follow 4 then 8, then 2, then the others.

ELNHY O DEO OH FIE KURAW MLNR EALD TY I ULT DTH
===================================================

What do you make of it?

[PS_HoHoHoCCH]

PROOFv1:0369010a1fb06eca9809b56f5d60d342b1febda1f91071c3087a068efa4a36df

[Puzzling_Pelican]

PROOFv1:d001b2bfa0c3c0db1caca09d03df271490392430f6f24e84d3c7eb3df589de46

[upsidedown]

“BIB CHIPHER 1”, “upsidedown”: PROOFv1:6bb8a6ed0816c0779a66c7be23a7b89e6fecf7775c92dfc79aaf48dd3975ecaf

At first I went in completely the wrong direction, but on the bright side I’ve come up with an idea for a new challenge.

[Robb27]

@ByteInBits
BIB CHIPHER 1
Plaintext in uppercase including appropriate spaces for the words in the sentence to the last word. This may, or may not, trim spaces from the original cipher text.
PROOFv1:c36dca357a8b5033047778dbe43b45028992f0dca3b6d1e7c2678ed6654971cc

[ByteInBits]

To All, for BIB CHIPHER 1.
As usual please use the SHA256 method of answering with the plaintext.

Do not say how to solve it or give clues for others.
Other comments welcome.

Thanks.

[harry]

Just a reminder, we have built a solution hiding system based on SHA256 that you will find on the deciphering tools page.

[ByteInBits]

@Puzzling_Pelican

If that is for BIB CHIPHER 1 Puzzling_Pelican plaintext
or
If that is for BIB CIPHER 1 Puzzling_Pelican plaintext
I do not get a match for either.

Any one posting answers please mention which/whose decode you are posting for.

Note my mispelt CHIPHER to be used please.

[Puzzling_Pelican]

BIB CHIPHER 1 and Puzzling_Pelican
It is odd that it does not give you a match. I am able to reproduce PS_HoHoHoCCH’s proof and so believe that the plaintext I have is correct.

[ByteInBits]

@Puzzling_Pelican My bad! A typo, I had a – instead of an _ in your name sorry.
You do have the correct code

[ByteInBits]

All codes checked and passed for:

@PS_HoHoHoCCH ••••• now that was a very quick solve!
Puzzling_Pelican •• there is little that gets unsolved by you!
@upsidedown ••••••• it was nice to read your comment
@Robb27 ••••••••••• you are very good, yet another solve

Wow, very fast solves by each one of you, I hope you all enjoyed the ‘challenge’

[PS_HoHoHoCCH]

The solution is slightly reminicent of one of the questions from this year’s NSU Cryptography Olympiad (another amazing cipher/mathematics competition that is really worth checking out if anyone can’t get enough of 10B-style challenges), so maybe some subconcious long-term memory miracle led me to the answer quickly haha. Still had lots of fun breaking it regardless!

• This reply was modified 1 week, 3 days ago by Harry.

[-IndyDoodle-]

Hi this is my first time doing the Cipher Challenge, I was wondering, after Practice Chapters, if you make a mistake on the actual thing, are you out or is it just based on points/not meeting the deadline? Any answer to this would be really helpful. Thanks!

[upsidedown]

You can submit an answer as many times as you like (within reason) and the highest scoring one is counted – as long as you answer before the first deadline you will get maximum points (you get fewer points as each deadline passes). Even if you don’t manage to solve one week’s cipher, you can always have a go at the next one. Your place on the overall leaderboard is determined by the sum of your scores.

[Elf_on_the_Shift]

For each of the challenges 1 to 10 for which you submit an entry for part B you will be awarded a score, based on the accuracy of your best submission for that challenge and the order in which we receive the submissions. Accuracy is be measured using the Damerau-Levenshtein metric. Time points will be based on a schedule published alongside the challenge. Accuracy is more important than speed, so we will use the lexicographic order on the pairs (accuracy, speed) to determine your position on the leaderboard. The scores for Challenges 4B, 5B, 6B, 7B, 8B, 9B and 10B will be aggregated to determine the Championship Leaderboard for the part B competition.

[ByteInBits]

ONCE YOU HAVE SOLVED AND SUBMITTED TO THE MAIN NCC CHALLENGE HAVE FUN WITH THESE.

One year TLW posted 2 steganographic (hidden messages.)
No one posted any replys and TLW did not post the answers.

I have since solved them and I think they are worthy of a re-post, so
I present them here. Along with one of my own, #3.
They are truly of the paper and pencil type.

I know that the Pro’s know but:
If you solve Do Not post the plaintexts or state how to obtain them.
If you want to prove you have a solve then use the method that the forum
has now adopted, i.e. the SHA256 in the tools section.

In your reply state :
@ByteInBits HIDDEN#1 or HIDDEN#2 or HIDDEN#3 whichever applies and your generated
PROOFv1:hashtext

Take your proofs using:
HIDDEN#1 your forum name PLAINTEXT
or
HIDDEN#2 your forum name PLAINTEXT
or
HIDDEN#3 your forum name PLAINTEXT
================================== Have fun!

HIDDEN MESSAGE #1
=================
••••••••••••••••••••••••••••••••••••••••••••••
TBIHAC2LR7QRRPOZNMHYINWJGIHIF6KLPEXMALQALCGYWR
WAYXTSB3EUDJ4FKLVSOY5ADL9TOAS0OBBOZ1SWVYU8LESF
39HAFUHRXXRMWUS2QCYIKW4NHWIAP5LJ7ELSLYALAQTWZG
AYP1SBMED8OIV0LGKOYBACLDTOBRTIBEOLNS6JRZYOVS
••••••••••••••••••••••••••••••••••••••••••••••

HIDDEN MESSAGE #2
=================
•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••
cannot undo nothing regarding ruined multimedia, the bureau linked agenda takes
multi orders then stays away offending you, every intel is kept, endless public
outcry, deduced each web received one article back even twitter
•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••

HIDDEN MESSAGE #3
•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••
Remember, you have to succeed, are you up for it? In some form, a little
observation is needed; pitiable without it so, condition yourself.
When it becomes evident that, you are on the right track you might, have a time
when you will need, to control and, conceal your great discovery and not
reveal, what it is that is said here that – you – wish – to – tell
•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••

• This reply was modified 5 days, 21 hours ago by Harry.

[Puzzling_Pelican]

I don’t really have too much experience with these kinds of ciphers and so a lot of my solving work was just guessing something that you could have done and trying whether it works, and sometimes I get lucky and get bits of plaintext and can work from there. I am curious whether there are ways of identifying the algorithm used by this class of ciphers without just brute forcing. Hopefully someone more experienced can answer this.
Anyways:
HIDDEN#1 || Puzzling_Pelican || plaintext = PROOFv1:a0cbf93f8db9ae9b3b60c3411b9236c8e4509bfce2eafaa9d95f17b15ba8bec1
HIDDEN#2 || Puzzling_Pelican || plaintext = PROOFv1:ffa90fe7ada389548961d890c6756ab0d6d0059c56ce43f2cc5c5004b48cdaf6
No progress on part 3 yet

[Puzzling_Pelican]

I think I have got part 3 now. I actually have two almost identical decrypts depending on how it starts, both of which I think could be correct (the 1st one matches upsidedown’s proof)
HIDDEN#3 || Puzzling_Pelican || plaintext = PROOFv1:af67c3890bf35d21d243b1f5c6e50b46110ed67fedf240c6ed2d85503e8c40a0
or
HIDDEN#3 || Puzzling_Pelican || plaintext = PROOFv1:fe6f9951db9d0774cc175faa806e42c1f082070d3a102272c3ef92ffc65462c4

[upsidedown]

@ByteInBits thanks for re-posting these (+ your own). Without giving too much away, I particularly liked TLW HIDDEN#1 because it required a bit less guesswork than the others.

HIDDEN#1 + upsidedown => PROOFv1:0294958a8395bf567b62a708d4b5f17e97216394685edd3728a462b497d3b755
HIDDEN#2 + upsidedown => PROOFv1:709c355603bb09ebe02481aa0b15cb0ebcf6d631d554ba5abbcbc02532a1da04
HIDDEN#3 + upsidedown => PROOFv1:04f325753961c59d8a33266938a40ceb6d30a33591213b9356605e39066e78fc

@Puzzling_Pelican I’m not sure there can be much method here, beyond just trying lots of different things. Statistical methods will be useless on messages this short. You could write a program to solve variations on these 3 ciphers, but it would break on any minor change. Maybe you could come up with some “base” set of transformations (expressive/general enough to encode lots of possibilities) and brute-force combinations of them. You could write a program to detect what you need to notice about #1 (and that program would have been helpful for various 10B’s).

[PS_HoHoHoCCH]

Bit late to the party but i wanted to solve all 3 before submitting.

HIDDEN#1 – PROOFv1:709e20862efabf8bc29e0b28b9767dff93f94ef6b14c206a45db87efa846fe42
HIDDEN#2 – PROOFv1:7beaaf8b44bd7bf3178253f144ef73e6135c021703aa3b178445bf49296a040b
HIDDEN#3 – PROOFv1:a737835b26adf8b007c6d55d7146f32e1e3172200118aa6ef93cba111b5eef73

The first one took me way longer than the other 2 haha, they were all very fun though. I believe they should be correct as I’m able to reproduce upsidedown’s proofs.

[ByteInBits]

@Puzzling_Pelican

Unfortunately I have no match for either of your PROOFs.

I am fascinated that that you may have made a meaningful sentence for them.

Now, so far the messages have passed the test of being kept from prying eyes.
Will that remain the case until after xmas when I will reveal all?
We shall see!

Of course they are not something you can usualy decode with software code,
but by careful observation on many a different theme. The receiver would of
course know how to extract the message.

[Puzzling_Pelican]

That is odd. I can reproduce the same proofs that upsidedown posted. There is a chance that both of us have found some alternative decrypt however the decryption method feels intentional and the message looks like what I would expect something posted on the forums to be like.

[ByteInBits]

@Puzzling_Pelican, yet once again sorry.

After re-checking you do have the correct proofs and for those 2 a very
fast solve. I feel you will get #3 soon.

So, what happend this time?
I don’t know for #1 but for #2:
I had done a pre-compiled proof list for all the most likely solvers
and in yours ( ho why did it have to be yours ) the 2nd T was missing
in the 1st word, again sorry, if it makes for your anoyance.

Like I said elsewhere you are up there with the best (wish I was).

[Puzzling_Pelican]

@ByteInBits no worries. I enjoyed all 3 (I posted my solution to #3 not long after upsidedown beat me to it) and especially enjoyed how different these 3 (4 including BIB CHIPHER 1) were compared to the ciphers I am used to. Thank you for posting them.

[ByteInBits]

@upsidedown

The first to read all three messages!
All proofs correct, and another quick response, wow.

Plaesed you enjoyed something a little different.

[ByteInBits]

Um these posts are out of order had to scroll for your latest post.

@Puzzling_Pelican

Yep you got it! The #3 first proof that is, I’ll never know what your 2nd text was but it
makes me wonder if you got the 1st by the logic intended. Anyways well done and thanks
for having a go at them. Do you have a like for one of them in particular?

[ByteInBits]

@PS_HoHoHoCCH

Nice to see you have solved these too.
So nothing is HIDDEN from your eyes, all 3 proofs are correct.

[Robb27]

@ByteInBits
I am a little late to this puzzle as I had some holiday. I actually got 2 quicker than 1. I may have seen something similar in the past, I don’t know, but I just saw 2 more or less straight away.

HIDDEN#1 PROOFv1:b79afd5c6911c4329eda42f34401a9f50a2303ffe6870220280fe76639275d92
HIDDEN#2 PROOFv1:ec7d4b63f5d70912f97ad92e2cf43d7b163bcf12180ed4d39b655cea6a232b9b

I think this is correct for #3. It is the only sensible sentence I could make anyway and also agrees with Puzzling_Pelican’s second #3 proof.
HIDDEN#2 PROOFv1:effb1e35dea63aab5662c4c6873150528da6171f982a792e713eaf5e4fe52940

Thanks for something a little different.

BTW – The Roman Legion NCC in 2017 had a steganograhic part in challenge 5A with an embedded image. For anyone reading, it is worth looking up for an interesting challenge. Find it courtesy of Madness Unofficial NCC repository

[ByteInBits]

@Robb27 Hi there,
it matters very little as to when someone posts answers but more important is
that as many as can do so. There are many hundreds signed up so I was expecting
others beside the elites.

Your #1 and #2 check out but not #3, I mentioned elsewhere that
Puzzling_Pelican’s second #3 proof was incorrect.
If you are using the correct logic it can only come out correct.

I propose that a pre-proof of the expected text be made by setters so that a
check of the intended plaintext can be made before posting a self-name proof.
Using : [test] [text] [PLAINTEXT]

And on that proposition here they are for the 3 HIDDEN texts
#1 PROOFv1:87b3c9c1c80374b127a8af44260613877d941702adddcd6786e03b65cace3ecd
#2 PROOFv1:ffec5e58f50454894312edd30b7391e2fa528fceef82f4b4b2d2b2e6d38b51ed
#3 PROOFv1:a6d85978a6ce7a050ea1d799d7a81da0547884fc6a04b78d694bcbedcdc96cc7

[Robb27]

@ByteInBits
OK, I may have made a similar mistake as PP in that case for #3. Is this correct?
HIDDEN#3 PROOFv1:c3acdd5c743cf9675888475766bb6123cf33cd9e767fd61a0e0d555bcd5c5ce3

[ByteInBits]

@Robb27
Yes your HIDDEN#3 is now correct.

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