You don't just 'run a cipher' you need a mode of operation. Dr Mike Pound explains some relative to the Feistel cipher.

*This video was filmed before any social distancing guidelines came into effect*

EXTRA BITS:    • EXTRA BITS: Feistel Modes of Operatio...  
Feistel Cipher Video:    • Feistel Cipher  Computerphile  

Mike's code:
github.com/mikepound/feistel

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This video was filmed and edited by Sean Riley.

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

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