11 August 2000

These messages respond to the 1933 secret patent for an encryption machine by William Friedman, senior cryptologist for the US Army agency predecessor to the National Security Agency: http://cryptome.org/nsa-crypto33.htm

From: owner-intelforum@mclean1.his.com
Date: Tue, 8 Aug 2000 18:21:13 EDT
Subject: Re: Better Late Than Never (Crypto)
To: intelforum@his.com

In a message dated 08/08/2000 7:56:12 AM Eastern Daylight Time, thomsona@flash.net writes:

<< On 1 August 2000, sixty seven years after the initial application, W.F. Friedman was granted a patent on a crypto machine:

http://patent.womplex.ibm.com/cgi-bin/viewpat.cmd/6097812

Allen Thomson>>

I find this item very interesting. While I have no personal knowledge of the invention itself, there are several historical facts which may be of interest. The application date, 1933, was three years after Friedman hired three topnotch mathematicians into the new Signal Intelligence Service;--Frank Rowlett, Abraham Sinkov, and Solomon Kullback.  This invention was one of several developed during this period, all of which were put under  Patent Secrecy Orders. While they were developed on government time by paid government employees the U.S. Congress nevertheless later recognized the great value of the personal contribution and voted $100,000 first to Friedman and later to Rowlett. Those were princely sums in the post-WW2 period.

That this patent has now been issued to the National Security Agency, the successor agency to the SIS, suggests that, at long last, the Patent Secrecy Order has been lifted.

Mike Levin

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

To: intelforum@his.com
From: Wes Freeman <wesf@worldnet.att.net>
Subject: Re: Better Late Than Never (Crypto)
Date: Wed, 9 Aug 2000 05:09:14 +0000

At 12:03 PM 8/8/00 -0400, John Young wrote:

>We would appreciate information on the use of William
>Friedman's crypto machine patent, its production model
>if any, and if the machine was produced, how it was used.
>Is there, was there ever, a working model, for example.

In his book 'The Story of Magic', Frank Rowlett states that construction of the M134 was undertaken by a 'private contractor.' Friedman himself delivered two each of the machines to the Canal Zone, Hawaii, and the Philippines in the summer of 1939. The machines were to be used for communications between Washington and the three overseas stations, so presumably more than six were built.

The operation of the SIGABA machine (M134-A, etc.) is different from the machine described in Friedman's *recent* patent.

wes freeman

Date: Wed, 09 Aug 2000 21:46:30 +0100
To: intelforum@his.com
From: Ralph Erskine <rerskine@clara.co.uk>
Subject: Re: Better Late Than Never (Crypto)

>In his book 'The Story of Magic', Frank Rowlett states that
>construction of the M134 was undertaken by a 'private
>contractor.' Friedman himself delivered two each of the
>machines to the Canal Zone, Hawaii, and the Philippines in
>the summer of 1939. The machines were to be used for
>communications between Washington and the three overseas
>stations, so presumably more than six were built.

The patent application in question was No. US1933000682096, made on 25 July 1933 (see-

http://www.patents.ibm.com/details?pn=US06097812__s_all=1

A US file states that-

[begins]

25 July 1933: Secret patent application (Serial No. 682,096) for M-134-T2 (M-134 and M-134-A) is filed by the Chief Signal Officer on behalf of Principal Cryptanalyst, United Stated Army.

15 June 1935: Chief Assistant to Principal Cryptanalyst, United Stated Army conceives principle of using electric rotors in cascade formation to produce irregular sequence of keying characters. The rotors would replace the keying tape as keying control.

23 March 1936: Secret patent application, Serial No. 70,412, for principle of using rotors in cascade formation to produce irregular sequence of keying characters (principle of present M-134-C) is filed by chief Signal Officer on behalf of Principal Cryptanalyst, United States Army and his chief assistant, jointly.

2 August 1938: Twelve (12) M-134's delivered to the Chief Signal Officer from Signal Corps Laboratories. (Contract W1077-SC 243).

[ends]

So the patent was for the M 134-T2, a tape-driven precursor of Sigaba. The "Chief Assistant to Principal Cryptanalyst" was Frank Rowlett, who invented the advanced "rotor cascade" principle.

Sigaba was so secret during WWII that instructions were issued forbidding any non-US citizens from even seeing it. The British shared their advanced cipher machine, Typex, with the US, but the US Chiefs of Staff barred Sigaba from being shared with the British. The Chiefs of Staff decision was a sore point with the Government Code and Cypher School - and some sections of the US Navy, which believed that Naval Cypher No 3 ("the convoy code" used in the North Atlantic) was insecure (it was indeed often being read by the B-Dienst).

Adapters were made in the US for Sigaba and Typex to make them compatible. The resulting "Combined Cipher Machine" came into service in the Atlantic in late 1943, and was eventually used by all five British and American armed forces.

Ralph Erskine