Richard Walton

sunflowerplateAI and Robotics

Nov 21, 2013 (3 years and 7 months ago)

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Mechanising Cryptography

Professor Richard Walton CB

Cryptography is concerned with
the application of technology to
the problem of encrypting and
decrypting a message.


The Mathematics is
subordinate to the technology

20
th

Century Cryptography


Development of Crypt in the 1900s


Manual Methods


Slow


Laborious


Error
-
Prone


Need to mechanise


Importance of technology for design


Nature of technological constraints


CRYPTOGRAPHY

Cost

Cost

Security

Usability

Cost

Cryptanalysis 1918


Knowledge of language


Frequency Analysis


Key Re
-
use (Depth)


Skill Requirement:

To solve crossword puzzles

in foreign languages

Rotor Machines

Rotors

Commercial Enigma

Enigma

Enigma

Army

Navy

Navy


4 wheel

Early Machine Cryptography


Limitations of Security Design


Balance Security against Cost


Usability


Human Factors


Electronics


1960
-
1980


Shift Registers and Simple Logic Gates


Linear Algebra


Galois Theory


Rich Mathematical structure


Rigorous Analysis


Expensive Components

Large Scale Integration


Application Specific Integrated Circuits


Complex Algorithms


Tailored to purpose


Standard Cryptographic Primitives


Software and Firmware


Public Key Cryptography


Key Management


Non
-
Secret Encryption


Ellis, Cocks & Williamson


Beyond 1970’s technology


Widespread after 1985


Search for easier solutions


Elliptic Curve Cryptography



Next Challenge

Quantum Computers destroy

current Public Key algorithms


Find new algorithms to resist

Quantum Computer attacks

Mechanising Cryptography

Acknowledgement

Illustrations concerning Enigma in this presentation
have been taken from the user manual for Enigma


E
by Paul Reuvers & Marc Simons.

For details of Enigma
-
E, which is available for purchase
from Bletchley Park Museum, see www.xat.nl/enigma
-
e/