The Influence of Computers on Cryptography
The first role of computers was to gather statistics and
perform 'brute-force' searches of ciphertext using some heuristics.
Traditionally,
convoluted,
obscure,
and undisclosed algorithms requiring long keys were used to encrypt text.
More recently the focus has changed to support simple,
open algorithms,
but with complex 'solutions'.
The algorithmic inverses themselves are intended to be so complex that
brute-force techniques take millions of years to succeed.
- An algorithm's strength is not simply derived from its keys' length,
but from its peer evaluation and public review.
- A weak algorithm is one whose algorithm and implementation are
not available, and whose strength would be compromised if these were made
public.
In 1883
Auguste Kerckhoff
stated as one of his six axioms of cryptography:
|
"If the method of encipherment becomes known to one's adversary,
this should not prevent one from continuing to use the cipher as long as
the key remains unknown."
|
CITS3002 Computer Networks, Lecture 12, Cryptography's role in networking, p5, 22nd May 2024.
|
CITS3002