PERPLEX CITY, SEASON ONE
WARNING: THIS PAGE CONTAINS SPOILERS.
- 1 Key Details
- 2 Key Words and their Definitions
- 3 Solution Ideas
- 3.1 Code Analysis
- 3.2 Secret Message Interpretations
- 3.3 Solitaire Cipher
- 3.4 Two messages encoded with the same code
- 3.5 Mirdek Cipher
- 3.6 Possible Creators of the Djinn Worm
This page summarises the information currently contained in the unfiction Thread here: 
It is likely that this page may be quite large. When considering whether or not to read it prior to posting on a forum, consider that the alternative is to read all 43 pages of forum thread.
- Details of this card have been taken from the Perplex City Card Catalog 
N.B. There is an error on this page. the code that reads XAWHU should read XAWJUThe card catalog typo has since been fixed.
- Card Author: Garnet
Last year, someone found a weakness in the Academy's computer security systems and accessed several files using a program called the Djinn Worm. I helped the Perplex City Police to plug the leak but we still didn't know who was responsible and all our leads had gone cold. Then I received an anonymous note suggesting I should be at the Five of Cups bar one night.
I was waiting for something to happen while playing poker, when one of the players at my table cashed out and he subtly indicated he wanted to talk to me. At a convenient pause in the game, I walked over to meet him at the bar, where he quickly pressed a pack of cards into my hand and whispered, "If entropy wins, outward looks should leave you cold." He then promptly walked out.
When I returned home, I spread the cards out on my table and looked for any marks or signs, but they were all new and untouched, apart from one joker which had a star on it. It took me some time to figure out what he was trying to tell me - can you decode the message and find out who created the Worm?
Side of the pack has the letters below. The bolded characters disappear under heat [].
EODMF XRUTH WBBMC HGFIB LXCQY WEZFL ITHPJ LFHWY ETKWY LJOTY YNGYJ BIOGI FUVMR
XIHGU RAGXH NQHRS XAWJU FJTAM SMMOS MVBAA KPGVV WXOVM YKZPL LUL FHURG IFULP
An interesting anagram of the bolded letters: FLUXED FROM TURF HIGH UP.
Cognivia's main research and development division is based at their campus on the south side of Polygon Park. Security is exceptionally tight to prevent industrial espionage, and the campus and buildings are said to be state of the art; rumours persist that Cognivia even has its own private subway station. Cognivia maintains strong links with the Academy and University, hence their selection of a site close to both. The corporate headquarters of Cognivia is based in Ascendancy Point.
Other Pertinent Card Information
Examine the card more closely. If you're feeling cold, you're overly sensitive, as for the code, everything you need is there
The cards are 'Motor Brand Casino Quality playing cards' 
There was a great deal of discussion on this topic, largely centering around discovering the make of the bike. The discovery of the 'correct' card manufacturer has discredited this line of investigation. Particular credit should go to modern_hero for spotting this after 33! pages of discussion 
- The side of the box contains the text "Made in China"
- As noted first by oliverkeers13 (one and two), there appear to be tiny suit symbols in the grey title bar at the top of the card (see picture here), apparently in the order Hearts, Clubs, Spades, Diamonds. (Although as they wrap around, CSDH, SDHC and DHCS may also be applicable.) Is this relevant to some starting deck order?
Key Words and their Definitions
A number of significant words occur in the text. The generally agreed meaning for each is displayed (where links, if available)
- As defined here: 
- Symbol S For a closed thermodynamic system, a quantitative measure of the amount of thermal energy not available to do work.
- A measure of the disorder or randomness in a closed system.
- A measure of the loss of information in a transmitted message.
- The tendency for all matter and energy in the universe to evolve toward a state of inert uniformity.
- Inevitable and steady deterioration of a system or society.
- As it pertains to cards:
- to shuffle (see also here: )
- Entropy Coding 
- In information Theory []
- As defined here: 
- Djinn is derived from a Genie (Jini) (http://en.wikipedia.org/wiki/Djinn)
- Jini is a network architecture for the construction of distributed systems (http://en.wikipedia.org/wiki/JINI)
- Jini defines a lookup service that is a fundamental part of the federation infrastructure for a djinn, the group of devices, resources, and users that are joined by the Jini technology infrastructure (http://java.sun.com/products/jini/)
- Jini uses PKI encryption
- Five of Cups
- Well known bar in PXC See here
This section covers analysis of the letters appearing on the side of the box
- 128 Characters
- 20 Disappearing characters
- 108 Plain Characters
Including the disappearing text:
1-D, 2-CQZ, 3-EKS, 4-JP, 5-ABORTV, 6-IWX, 7-GUY, 8-FLM, 9-H
Only the standard characters:
0-D, 2-CENQZ, 3-KPRS, 4-JOTU, 5-ABFIVX, 6-GW, 7-HLMY
- The distributions do not match the standard character distribution for English 
- The distribution does not seem random 
- However, a G-test  on the distributions show that there is no evidence that all characters are not equally likely.
108 Characters as encoded deck
54 Letter pairs allows for one letter pair for each of the 54 playing cards. The problem arises in that there is no logical pairing of the characters that creates 54 unique pairs. This would provide an encoded deck for the Solitaire Cipher.
Two Messages encoded with the same key 
Secret Message Interpretations
The message passed to Garnet was: "If entropy wins, outward looks should leave you cold"
- This could could simply be a reference to the heat disappearing letters.
- This could make reference to the outward facing cards: 
- Jack of Hearts
- Jack of Spades
- King of Diamonds
- It has been suggested that the odd word usage may indicate something else, such as an anagram or a mnemonics.
- "If entropy wins, outward looks should leave you cold" is an anagram of "Look close and you will find out the password, voyeur"
The Solitaire Cipher was designed by Bruce Schneier for the book 'The Cryptonomicon'. Details of the cipher can be found at Bruce Schneier's site, here: 
This was initially proposed due to the existence of the starred joker, as per the ciphers description in the above book.
- Mr. Schneier responds to an email: 
Various Solitaire implentations are available here: http://www.schneier.com/solitaire.html However, it's your job to figure out how the key is buried in the phrase. Good luck, Bruce
The possibility of brute forcing has been mentioned at various points. The potential for this attack to be successful depends on whether or not you believe that the card sequence is the Prime numbered playing cards (Playing card symbols).
The nature of a solitaire cipher is that it generates a string of random characters which are then added to the plain text to produce the cipher text (see Wikipedia:Stream Cipher)
Because of this, a cipher text of XDFGW RESDF could translate to both SENTE ROCKS and SENTE SUCKS. This broadly implys that every possible 108 character string can be produced from the cipher text, and hence brute forcing is not possible.
If you assume that the prime numbered cards are part of the solution, then while this narrows the number of possible strings down, it is still possible to produce a number of strings that are a 'legitimate' solution.
- Online: 
- Authored by Brian Enigma (Brute Forcer): 
- Authored by Danives (Dictionary Attacker): 
- Changes to Perl code by Sh1ft (Deck Order Preset): 
Sources for the initial deck encoding
- Encoded from the 108 non-disappearing characters
- Standard Deck ordering of A-K, C,D,H,S (discussed here: )
- Order of cards as they come out of the box as viewed face up: 
Joker - Colour
Joker - Black and White
Diamonds - A T T F F S S E N T J Q K
Clubs - A T T F F S S E N T J Q K
Hearts - A T T F F S S E N T J Q K
Spades - A T T F F S S E N T J Q K
- Order of cards as used in the Solitaire algorithm: each card is converted into a number from 1..52 using the following method:
Clubs: A T T F F S S E N T J Q K - (1..13)
Diamonds: A T T F F S S E N T J Q K - (14..26)
Hearts: A T T F F S S E N T J Q K - (27..39)
Spades: A T T F F S S E N T J Q K - (40..52)
- This idea has been reasonably discredited: 
Hello Dan, Thanks for your email. You do not need any other puzzle cards in order to solve card 243- shuffled. Regards, Perplex City Customer Services
Sources for the Cipher Text
- The 108 standard characters
- The 20 disappearing characters
- The phrase 'If entropy wins, outward looks should leave you cold' 
- The Motor Deck of Cards (from the side of the box)
- Motor Brand High Quality Playing Cards
- Thoth Tarot Deck 
Two messages encoded with the same code
A description of this first arose here  but subsequently received very little attention, recently the theory has received new attention, and a good description of how to do it can be found in this post 
Details of the Mirdek cipher can be found here: 
This is another Card based cipher designed to handle the errors found in solitaire. It hasn't been widely investigated at this point.
Possible Creators of the Djinn Worm
Hello - You're quite right, Professor Kiteway was involved. If you can tell me what the message you deciphered was, I can shed some light on the mystery for you. Best Wishes, Garnet.
|Please see Brian Enigma's impressive Card Catalog for a sorted, comprehensive listing of cards.|