What Not To Write On Your Security Clearance Form
[REDACTED]
Date: 01 Apr 88 1620 PST
From: Les Earnest < LES...@S... >
Subject: The "previous account" referred to in RISKS-6.51
e-t-a-o-n-r-i Spy and the FBI
A friend named Bob and I read the book ``Secret and Urgent,'' by Fletcher Pratt [Blue Ribbon Books; Garden City, NY; 1942] which was an early popular account of codes and ciphers. Pratt showed how to use letter frequencies to break ciphers and reported that the most frequently occurring letters in typical English text are e-t-a-o-n-r-i, in that order. (The letter frequency order of the story you are now reading is e-t-a-i-o-n-r. The higher frequency of ``i'' probably reflects the fact that _I_ use the first person singular a lot.) Pratt's book also treated more advanced cryptographic schemes.
Bob and I decided that we needed to have a secure way to communicate with each other, so we put together a rather elaborate jargon code based on the principles described in the book. I don't remember exactly why we thought we needed it--we spent much of our time outside of school together, so there was ample time to talk privately. Still, you never could tell when you might need to send a secret message!
We made two copies of the code key (a description of how to encrypt and decrypt our messages) in the form of a single typewritten sheet. We each took a copy and carried it on our persons at all times when we were wearing clothes.
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