Old School Cryptography

Auguste Kerckhoffs

Auguste Kerckhoffs (apart from having a very long name ) is credited with writing about the concept of secure systems in an attempt to improve the practice of encoded message passing in the French Military. Even today, his essay “LA CRYPTOGRAPHIE MILITAIRE” makes for a fun read (even through the fog of Google Translate). It includes some handy principles anyone looking at crypto-systems should consider:

  1. The system must be substantially, if not mathematically, undecipherable;
  2. The system must not require secrecy and can be stolen by the enemy without causing trouble; 3.It must be easy to communicate and remember the keys without requiring written notes, it must also be easy to change or modify the keys with different participants;
  3. The system ought to be compatible with telegraph communication;
  4. The system must be portable, and its use must not require more than one person;
  5. Finally, regarding the circumstances in which such system is applied, it must be easy to use and must neither require stress of mind nor the knowledge of a long series of rules.

He also cites a cipher system from Francis Beaufort at the end of the paper, another very interesting character from history.

Sat 01 May 2010