TOP SECRET

MISSION BRIEFING

You are about to assist Alan Turing at Bletchley Park, 1941.

Five levels. Five real techniques used to break Enigma during World War II.

01 Caesar Cipher — Rotate the shift wheel to decode the intercepted message.
02 Substitution Cipher — Use frequency analysis to map cipher letters to plaintext.
03 Enigma Rotors — Select the correct rotor combination from four options.
04 Crib Dragging — Slide the known word across the ciphertext to find the clash-free position.
05 The Bombe — Spin the dials to satisfy all six circuit constraints.

Use the HINT button if you're stuck. Use REVEAL to see the answer.

LEVEL 1 OF 5
CLASSIFIED
SUBJECT: Turing, Alan M.
STATION: Bletchley Park, Dept 10
DOCUMENT: Cypher Tutorial Dossier
SECURITY: TOP SECRET / EYES ONLY
TURING, A.
Ref: BP-1941
DECRYPT_SYS_V4.1 // DECODING WORKSPACE
STATUS: STANDBY
Ciphertext Message (Intercepted)
EOHWFKOHB SDUN
CIPHER
PLAIN
SHIFT: 0
DECODED PREVIEW
EOHWFKOHB SDUN
Ciphertext (Frequency Map Activated)
Letter frequencies in ciphertext:
Ciphertext Message
FLR ZPV FZO VXN PXN
R1
R2
R3
A-B-C
T-U-R
M-C-K
W-E-T
Enigma Crypt Message (Align the Crib below)
W
E
T
T
E
R
Alignment Position: 0 / 10 CHECKING ALIGNMENT...
Partial Decoded Output (Calibrate the Bombe)
THE FATHER OF CS: _ _ _ _ _ _
D1
▴
A
▾
D2
▴
A
▾
D3
▴
A
▾
D4
▴
A
▾
D5
▴
A
▾
D6
▴
A
▾
Bombe Diagnostic Status
Circuit Alpha: Drums 2 & 4 energize diodes U and I respectively.
Circuit Beta: Drum 1 sends impulse to Drum 2 minus 1 unit.
Circuit Gamma: Diagnostic pathway: Q < Drum 3 < S.
Circuit Delta: Indicator lamp 5 glows for contact N.
Circuit Epsilon: Drum 6 voltage stabilized at position G.
Circuit Zeta: Feedback loop: No rotor setting duplicated in pathway.
DECLASSIFIED