17 June 2000

From: dalvarez@stmarys-ca.edu
Date: Sat, 17 Jun 2000 17:29:49 -0700
To: intelforum@his.com
Cc: BletchleyPark@Cranfield.ac.uk
Subject: Korean War Comint

The latest issue of "Intelligence and National Security" (vol. 15, no. 1: spring 2000) includes a pathbreaking article by Matthew Aid on American communications intelligence during the Korean War.  The article's revelations concerning American intercept and decryption operations are especially important in view of the reluctance by the National Security Agency to declassify materials dealing with the war in Korea. 

The revelations include (p. 26) an apparent (though perhaps limited) success by American cryptanalysts against Chinese one-time pad (OTP) ciphers.  On top of the VENONA achievement and the solution of the German foreign ministry's high-grade cipher (known to U.S. codebreakers as GEE) during WWII, this success against Chinese OTP would mark now the third example that has come to light of a theoretically "unbreakable" cipher falling to cryptanalytic attack. 

Of course, in the VENONA case the pads were re-used, so that one might more accurately refer to a "two-time pad."  Still a student of intelligence history might well wonder how many more times OTP systems succumbed to attack.

David Alvarez

Intelligence Forum (http://www.intelforum.org) is sponsored by Intelligence and National Security, a Frank Cass journal (http://www.frankcass.com/jnls/ins.htm)