"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. http://www.nsa.gov/public_info/_files/tech_journals/Some_Principles.pdf 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."