XOR encryption is flawed. Professor Brailsford explains the zigzag method that can reveal the precious key stream.

Fishy Codes – Bletchley's Other Secret:    • Fishy Codes: Bletchley's Other Secret...  
XOR and the Half Adder:    • XOR & the Half Adder  Computerphile  
Colossus & Bletchley Park:    • Colossus & Bletchley Park  Computerp...  
5 Hole Paper Tape:    • 5 Hole Paper Tape  Computerphile  

The Professor's Supporting Documents:

Sean/Dave ZigZag document: http://bit.ly/computerphileZigZag
C Program to play with: http://bit.ly/ComputerphileZigZagCprog
The real life decryption: http://bit.ly/ComputerphileTiltman
Teleprinter codes: http://bit.ly/computerphile5holetape

  / computerphile  
  / computer_phile  

This video was filmed and edited by Sean Riley.

Computer Science at the University of Nottingham: http://bit.ly/nottscomputer

Computerphile is a sister project to Brady Haran's Numberphile. More at http://www.bradyharan.com