Defcon 21 Badge Challenge Walkthrough Part 1

I was in one of two teams that completed the Defcon Badge Challenge this year. In part one of this walkthrough I’ll provide solutions for the Lanyard and the Badges. Part 2 will have the Posters. Enjoy!

Lanyards:
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All four lanyards laid out have a bass clef and then a series of dots that correspond to the musical notes:

ADDADEADACEBADGE (ADD A DEAD ACE BADGE)

Badges:
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There are 4 suits (Smileys, Rotaries, Locks, Disks). On the back of each card was a 3-bit number, cipher, and a symbol.

3-digit number
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The 3-bit number is 000 – 111 (0 – 7). Each card in each suit has a unique number with one exception.

Symbols
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Each suit has a unique symbol.

Smileys = e
Disks = Pi
Locks = Grey Code ( http://en.wikipedia.org/wiki/Rotary_encoder )
Rotaries = linear Feedback Shift Register ( https://en.wikipedia.org/wiki/Linear_feedback_shift_register )

Each of these symbols give a clue to the true order of the cards in each suit.

Ciphers
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Smileys:

When covered to letters (based on 1 = A, 2 = b, etc) and then ROT13:

7 – [000] BUTTHISISFUNRIGHT
10 – [001] BUTSOMETIMESLEADSASTRAY
5 – [010] TRYSOMETHINGELSE
2 – [011] ANDYOUWILLSEE
Q – [100] THATFINDINGANSWERS
J – [101] MAYTAKEYOUDOWN
K – [110] PATHSNOTOFTENREPEATED
A – [111] NOTALLWHOWANDERARELOST

Which could be ordered to say:

Try something else and you will see that finding answers may take you down paths not often repeated but sometimes leads astray not all who wander are lost but this is fun right.

paths not often repeated is a clue that you must use the digits of pi and e going down them picking out numbers 0 – 7 before they are repeated in order to get the real order of the cards.

Disks:

When converted to letters and ROT13

K – [000] ROTTHIRTEENPROBABLYISNTRIGHT
7 – [001] BUTTHISISFUNRIGHT
10 -[010] THOUGH HIS MIND IS NOT FOR RENT
A – [011] DONT PUT HIM DOWN AS ARROGANT
Q – [101] RIDING OUT THE DAYS EVENTS
J – [110] CATCH THEMISTCATCHTHEMYTH
2 – [111] CATCHTHEMYSTERYCATCHTHEDRIFT
5 – [100] HISRESERVEAQUIETDEFENSE

could read:

ROT Thirteen probably isn’t right but this is fun right though his mind is not for rent don’t put him down as arrogant riding out the days events catch the mist catch the myth catch the mystery catch the drift his reserve a quiet defense

These are lyrics to the Rush Song Tom Sawyer ( http://www.youtube.com/watch?v=KNZru4JG_Uo ) with a message about ROT13 not being right

Locks:

When converted to letters and ROT13

2 – [000] THESKYSWI
7 – [001] LLCLEARUP
K – [010] NOTINBLAC
J – [011] KANDWHITE
5 – [100] BUTSHADEO
10 -[101] FTHEBITSH
A – [110] ELPYOUTUR
Q – [111] NTHISKEYX

Could read:

The skys will clear up not in black and white but shade of the bits help you turn this keyx

This is a clue that you must use grey code to reorder the cards
The “x” padding is a clue about using OTP for later

Rotaries:

Just convert to letters

Q – [111] THE FIRST IS THE LAST
A – [001] IN THE REAL ORDER THE
J – [010] FIRST IS THE LAST BE E
5 – [011] XCLUSIVE OR HAS IT RE
7 – [100] GISTERED THAT TAP AT
K – [101] ZERO AND ONE WILL BE A
2 – [110] LL THE FEED BACK YOU N
10 – [111] EED IN THE REAL ORDER

could read:

The first is the last in the real order the first is the last be exclusive or has it registered that tap at zero and one will be all the feedback you need in the real order

This is a clue that you must use the linear feedback shift register drawn on the back of the cards to reorder them

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Ready to continue. Here’s Part 2 –>