Donate for the Cryptome archive of files from June 1996 to the present

24 December 1997: Link to The New York Times report

17 December 1997
Thanks to Steve Bellovin

See related CESG paper on the history of PK crypto: http://cryptome.org/jya/ellisdoc.htm


To: cryptography@c2.net
cc: Matt Blaze <mab@crypto.com>
Subject: Re: secret history of the development of PK crypto 
Date: Wed, 17 Dec 1997 14:13:34 -0500
From: Steven Bellovin <smb@research.att.com>

There is, I think, a lot more that is to be learned about the development
of public key crypto inside of assorted agencies.  Diffie notes that in
the 1986 Encyclopedia Britannica (I haven't checked later editions), the
director of NSA claimed (without substantiation) that NSA had had public
key crypto a decade earlier than Diffie and Hellman.

Let me add what little I can.  At the Fairfax conference a few years ago,
Whit Diffie organized a Festcolloquium in honor of Gus Simmons, who
was retiring.  Gus told of how he learned of public key crypto -- the same
way many of us did, by reading Martin Gardner's column in Scientific
American.  Simmons was on his way to Australia to give a talk; he said he
was immediately struck by the implications of this technique for nuclear
weapons command and control -- his field -- so he tore up his talk and
made up a new one on the plane.  It seemed clear, at that point, that he
had not known of the technique.  (An alternative explanation, of course,
is that he knew of it but couldn't speak about it until it was
rediscovered.  I did not get that impression at the time.)

The next speaker was someone who had recently retired from the upper
echelons of NSA.  (His name escapes me; Matt, do you remember who it was?)
He spoke of National Security Action Memorandum 160 (from June 6, 1962),
entitled "Permissive Links for Nuclear Weapons in NATO".  The claim was
that this memo -- signed by President Kennedy and endorsing a memo from
his science advisor, Jerome Weisner -- was the basis for the invention
of public key cryptography by NSA.  Simmons nodded in vigorous agreement.

When the conference was over, Matt Blaze called up the Kennedy Library in
Cambridge, MA, and asked about getting a copy of the memo.  It was
classified -- but the person to whom he spoke initiated a declassification
review.  Fairly promptly, he received a sanitized copy.

This version has been sitting around here for four years.  I've finally
gotten around to scanning them in and putting them up on the Web.  I'll
make up some fancier pages later; for now, they're sitting in
http://www.research.att.com/~smb/nsam-160/pg?.gif, where ? ranges from
1 through 7.  (N.B.  The files may not be there this instant, until the
staging daemon runs; they will be within a few hours.)

-----

[End Bellovin message]

http://www.research.att.com/~smb/nsam-160/pg1.gif through pg7.gif

Seven images mirrored on this site:

http://cryptome.org/jya/nsam160-pg1.gif (20.5K)
http://cryptome.org/jya/nsam160-pg2.gif (8.7K)
http://cryptome.org/jya/nsam160-pg3.gif (23.9K)
http://cryptome.org/jya/nsam160-pg4.gif (28.4K)
http://cryptome.org/jya/nsam160-pg5.gif (26.1K)
http://cryptome.org/jya/nsam160-pg6.gif (29.7K)
http://cryptome.org/jya/nsam160-pg7.gif (27.5K)

Images transcribed below.


THE WHITE HOUSE WASHINGTON June 6, 1962 SECRET RESTRICTED DATA NATIONAL SECURITY ACTION MEMORANDUM NO. 160 TO: The Secretary of State The Secretary of Defense The Chairman, Atomic Energy Commission The Director, Bureau of the Budget SUBJECT: Permissive Links for Nuclear Weapons in NATO 1. After an examination of the problem of installing per- missive links in nuclear weapons dispersed in NATO commands, I have decided we should now make the commitment to procure appropriate devices for all nuclear weapons, now dispersed and to be dispersed to NATO commands, for both non-U. S. and U. S. forces. (See attached memorandum to me from Dr. Weisner dated May 29. This decision corresponds to Alternative 5 of that memorandum.) 2. This will require a supplementary appropriation for the Atomic Energy Commission budget. The Secretary of Defense, the Chairman, Atomic Energy Commission, and the Director, Bureau of the Budget will work out the details of the budget pre- sentation. 3. At the earliest feasible time, the Secretary of Defense will submit for my approval a schedule for the installation of these devices in NATO weapons. In making this schedule, the Secretary should consult with the Secretary of State on the political problems arising from the existence of weapons assigned to U. S. Forces and weapons assigned to our allies. SECRET RESTRICTED DATA [Stamp] DECLASSIFIED E.O. 12356 Sec 3.4 NLK-94-5 By SKF NARA 11/22/93
SECRET RESTRICTED DATA - 2 - 4. The Chairman, Atomic Energy Commission, in con- sultation with the secretary of Defense, will carry on a research program on an urgent basis directed toward an examination of the feasibility and desireablity of more advanced permissive link devices with a wider range of capabilities. [Signature] cc: Dr. Weisner General Taylor Mrs. Lincoln Mr. Bundy (3) Mr. C. E. Johnson Mr. Kaysen (2) White House Files NSC Files SECRET RESTRICTED DATA
[Fax header following pages] DEC 15 '93 05:16PM ATT 908 949 0399 P. 6 through 10 [Stamp following pages] This document contains restricted data as defined in the Atomic Energy Act of 1954. Its transmittal or the disclosure of its contents in any manner to an unauthorized person is prohibited. SANITIZED COPY THE WHITE HOUSE WASHINGTON SECRET May 29, 1962 MEMORANDUM FOR THE PRESIDENT At your request I have reviewed, in consultation with the AEC and the DOD, the technical and cost aspects of equipping nuclear weapons dispersed overseas with permissive link hardware. The object of this review was to establish the program options that were technically available to implement such a program as rapidly as possible, and to determine the amount of supplemental funds that would have to be requested in the AEC FY '63 budget to ac- complish these options. A decision on this problem involves the following basic policy issues which, while not technical in themselves, are affected by the availability of equipment and the program timing and cost: (1) Should a permissive link be incorporated at this time in all dispersed nuclear weapons or just in those critical weapon systems with quick reaction, high yield, and long range (e.g., Jupiter missiles and quick reaction aircraft)? (2) Should a permissive link be incorporated at this time in all weapons dispersed to NATO (U.S. as well as non-U.S.) or just non-U.S. weapons? (3) Should a permissive link be incorporated at this time in weapons committed to NATO but based in the U.K. as well as weapons based on the European Continent? These policy issues raise the more basic question as to what ob- jective one is attempting to accomplish by incorporating permis- SECRET [Stamp] SANITIZED E.O. 12356 Sec 3.4 NLK-94-5 By SKF NARA 11/22/93
- 2 - sive link. A permissive link can attempt to meet any of the follow- ing objectives, each of which imposes increasingly difficult tech- nical problems. (1) Safeguarding weapons against actions by an individual psychotic; (2) Meeting the legal and political requirements of U.S. control; (3) Maintaining control against the unauthorized use of weapons by our own or allied military forces under conditions of high tension or actual military combat; (4) Assuring that weapons could not be use, if forceably seized by an organized group of individuals or by a foreign power. The first of these objectives (safeguarding against a psychotic) has already at least in part been met and the last objective (assuring weapons could not be used if seized) cannot be fully achieved without further development which would assure the self-destruction of the weapons if efforts were made to by-pass the permissive link. For the purpose of this review, I have not attempted to meet a specific objective but rather have analyzed the operational value of the best available equipment and attempted to determine how rapidly it could be incorporated in dispersed nuclear weapons. While the permissive link equipment presently recommended by the AEC leaves something to be desired and can clearly be much im- proved with time, I believe that this equipment can be used as the basis for a crash program since development quality hardware exists and initial production and installation could begin in the immediate future. Specifically, the AEC recommends that, if a permissive link program is undertaken on a crash basis, bombs for aircraft and warheads for longer range missiles be equipped with an electro-mechanical lock which would have to receive a preset numerical code in order to make the weapon operable. In the case of certain bombs which cannot be easily retrofitted with this equipment, as an interim measure pending the development of improved compatible permissive link hardware, SECRET
- 3 - mechanical combination locks would be installed to cover a socket into which an arming plug must be inserted. In the case of these bombs as well as short range missiles, such as Honest John and Nike Hercules, and teh 8-inch shell, the arming plugs would be stored in self-destruct safes. The proposed program does not include a specific hardware for the Davy Crockett missile which presents a particularly difficult problem because of its small size and possible forward deployment. The numbers which would operate both the electro-mechanical and the combination lock could be held at any echelon of command. If circumstances required, the combination could be held by the U.S. custodial officer himself. This procedure could therefore give the weapons the same state of readiness that they now possess. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. ...............................Despite the limitations of this equipment, I believe it would give further (and probably decisive protection against individual psychotics and would certainly deter unauthorized use by military forces holding the weapons during periods of high tension or military combat. ...................... .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. .... The question of the legal and political requirements of control were beyond the scope of my review. The question has been raised whether the installation of this develop- ment quality hardware on a crash basis might reduce th reliability of the nuclear weapons. However, in view of the simple nature of SECRET
- 4 - of this equipment and the method of installation, I believe that it is now generally agreed that it would not reduce the inherent reliability of the weapons. The weapons would, of course, not be operable if the combination number were not received from a higher headquarters. This is a communication and management problem, which can be very simple or complex, depending on the level of command at which the combination number is held and the degree of control maintained through coding procedures or the use of different combination number for different weapons. In its simplest form, it should be possible to handle this procedure wherever a "go code" can be transmitted which is presumably a requirement if any control is to exist. In any event, I wish to emphasize that, if circumstances demand, a decision can be made to release the combination number to the U.S. custodian with the field unit and thereby revert to the state of readiness and control that exists today. At my request, the AEC has estimated the cost and time for completion of the following five alternative programs, which I believe represent the full range of possible application of th permissive link on a crash basis to nuclear weapons dispersed to the European Theater: .................................................................. .................................................................. .................................................................. .................................................................. .................................................................. Alternative II - All nuclear weapons assigned to non-U.S. NATO forces exclusive of those assigned to U.K. delivery systems based in the U.K. Alternative III - All NATO weapons assigned to non-U.S. NATO forces including of those assigned to U.K. delivery systems based in the U.K. Alternative IV - All nuclear weapons assigned to non-U.S. NATO forces and all U.S. weapons committed to and dispersed to NATO exclusive of U.S. weapons on U.S. delivery systems based in the U.K. Alternative V - All nuclear weapons assigned to non-U.S. NATO forces and all U.S. weapons committed to and dispersed to NATO including those based in the U.K. and assigned to the naval attack aircraft on carriers based in European waters. The estimated completion date, total cost, and FY '63 cost SECRET
- 5 - for each of these programs is as follows: Estimated Date Total Cost FY'63 Cost Alternative Completed Installation ($ Millions) ($ Millions) __________________________________________________________________ I June 1963 2.9 2.9 II Oct. 1963 8.1 7.8 III Dec. 1963 10.2 8.7 IV Mar. 1964 15.2 10.7 V Aug. 1964 23.4 10.7 __________________________________________________________________ A supplemental to the AEC FY '63 Budget would call for obligation of the total cost of the program but expenditure of on the FY '63 cost of the program. On the basis of this review, I have concluded that it is technically pos- sible to equip on a crash basis all nuclear weapons dispersed to the European Theater with reasonably effective permissive link equip- ment at a relatively small cost. Therefore, the decision as to the ex- tent to which permissive link equipment should in fact be incorporated in dispersed weapons can be made solely in terms of broad policy con- siderations as to the desired objective. Whatever decision is made on the crash program to install permissive link equipment on dispersed nuclear weapons equipment, I would recom- mend that a vigorous program be undertaken to develop an improved electronic lock which would be incorporated directly in the electronic package associated with all future weapons so that the option of a per- missive link would always exist. This program should also include work to develop improved devices to retrofit the bombs and short range missiles which were equipped with combination locks only as an interim measure in the above crash program. I would also recom- mend that there be an aggressive research program to develop more advanced concepts of the permissive link including mechanisms to assure the self-destruction of a weapon if efforts were made to by-pass the permissive link. It is my understanding that the AEC has funds available to cover the R&D necessary for these advanced programs. [Signature] Jerome N. Weisner SECRET
[End]