Colossus: The First Electronic Computer
summary
Explains how Lorenz-encrypted teleprinter traffic yields a recoverable keystream when two messages reuse the same indicator, how Bill Tutte detects a 41-position repetition in a single bitstream, and how engineers at Donisthorpe/Donas Hill and Tommy Flowers turn that insight into Colossus hardware that processes 6000 chars in 1.5s. Prototype development takes nine months, Mark II machines follow at six-week cadence, about 10 operational Colossi exist by war’s end and use ~1200 valves each to automate the delta and chi/kappa wheel analysis.
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chapters (21)
- 0:00Introduction
- 3:15Lorenz SS42
- 5:00Teleprinter Code
- 7:54Lorenz
- 8:49How does it work
- 11:46Bletchley Park
- 15:11Weakness of the cipher
- 17:09How did that get there
- 19:20Summer of 41
- 24:46John Tilton
- 27:40The Chemist
- 29:10Bill Tut
- 30:40Lorenz S42
- 33:55Wheels
- 34:15Teleprinter
- 35:05Challenge
- 36:53Delta
- 38:12Frequency Count
- 38:31Breaking the Cipher
- 39:59The Robinson
- 40:29Colossus
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