Cryptography Reference
In-Depth Information
the existence of a
trapdoor
, a weakness known only to the designers, who
would thus have the ability to cryptanalyze messages at will.
Rumors abounded. Was DES an authentically secure cipher, or was the
entire process a sophisticated funkspiel cleverly devised by intelligence
agencies? The academic community worried that its expertise was effecti-
vely coopted to certify the validity of technological mole planted by the
NSA. In response, the NBS organized two workshops in September and
December of 1976 to discuss concerns with both a trapdoor and key size,
and subsequently approved it unchanged as a Federal Information Pro-
cessing Standard (FIPS) on January 15, 1977, with the provision that it be
revised every five years. No evidence of government tampering has ever
surfaced: “Claims which have repeatedly arisen and been denied over the
past 20 years regarding built-in weaknesses of DES remain unsubstantiated.”
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As the first cryptographic algorithm ever to be officially endorsed by the
United States government and the first to be openly exposed to cryptana-
lytic scrutiny by the cryptographic community, DES played a major role
in forging the structure and identity of modern cryptography on at least
three distinct levels: (1) the development of a civilian market for crypto-
graphic products; (2) the structuring of that market through standardiza-
tion; and (3) a validation process falling somewhat short of full technical
disclosure, resulting in increased suspicion from academic cryptographers
toward the intelligence establishment. The gap between these two com-
munities was soon to broaden into a wide gulf.
Conclusion
This short overview highlighted a number of recurring tensions in the
historical development of cryptographic theory and practice, namely the
importance of understanding security in relation to context, the practical
difficulties of fielding large-scale cryptosystems, the material embodiment
of cryptographic techniques, and the special conditions that obtain in a
scientific field of such import for national security.
The “Best” Method Depends on Context
Through different communication epochs, different cryptographic tech-
niques have been favored based on specific conditions, perceived security
needs, cultural preferences, legal environment, usability, and so on. A
