[cryptography] One Time Pad Cryptanalysis

John Young jya at pipeline.com
Thu Sep 26 11:29:31 EDT 2013

"Cryptanalystis make their living out of sloppy thinking and enthusiastic
over-ingenuity of designers of cipher systems."

Brig. Gen. J.H. Tiltman, "Some Principles of Cryptographic Security,"
NSA Technical Journal, Summer 1974.


Tiltman vaunts the One Time Pad but cautions there have been effective
decrypts exploiting enthusiastic sloppy thinking that OTP is unbreakable.
Most appears to involve non-decipher means and methods. The paper
redacts others presumably still effective.

For amateur ingenuity Tiltman footnotes:

"I remember an early example of the solution of the problem of producing
strictly one-time perforated tape. A Canadian engineer working for a
British intelligence organization in New York who knew nothing
at all about cryptography produced in 1942 an on-line machine called
TELEKRYPTON. He generated his tapes by pouring a mixture of
metal and glass balls through a hopper, the metal halls alone passing
current and perforating 5-level tape. He analyzed the result and saw
that it was biased, owing to the heavier weight of the metal balls, and
then changed the respective sizes of the balls to compensate for the
extra weight of the metal."

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