
                              RSAREF(TM):
          A Cryptographic Toolkit for Privacy-Enhanced Mail

                           RSA Laboratories
               (A division of RSA Data Security, Inc.)
                           January 5, 1993


This document copyright (C) 1992 RSA Laboratories, a division of RSA
Data Security, Inc. License is granted to reproduce, copy, post, or
distribute in any manner, provided this document is kept intact and
no modifications, deletions, or additions are made.


WHAT IS IT?

RSAREF is a cryptographic toolkit designed to facilitate rapid
deployment of Internet Privacy-Enhanced Mail (PEM) implementations.
RSAREF represents the fruits of RSA Data Security's commitment to the
U.S. Department of Defense's Advanced Research Projects Agency
(DARPA) to provide free cryptographic source code in support of a PEM
standard. RSA Laboratories offers RSAREF in expectation of PEM's
forthcoming publication as an Internet standard.

Part of RSA's commitment to DARPA was to authorize Trusted Information
Systems of Glenwood, MD, to distribute a full PEM implementation. That
implementation will be available this spring.

RSAREF supports the following PEM-specified algorithms:

     o    RSA encryption and key generation, as defined by RSA
            Laboratories' Public-Key Cryptography Standards (PKCS)

     o    MD2 and MD5 message digests

     o    DES (Data Encryption Standard) in cipher-block chaining mode

RSAREF is written in the C programming language as a library that can
be called from an application program. A simple PEM implementation
can be built directly on top of RSAREF, together with message parsing
and formatting routines and certificate-management routines. RSAREF
is distributed with a demonstration program that shows how one might
build such an implementation.

The name "RSAREF" means "RSA reference." RSA Laboratories intends
RSAREF to serve as a portable, educational, reference implementation
of cryptography.


WHAT YOU CAN (AND CANNOT) DO WITH RSAREF

The license at the end of this note gives legal terms and conditions.
Here's the layman's interpretation, for information only and with no
legal weight:

     1.   You can use RSAREF in personal, non-commercial applications,
          as long as you follow the interface described in the RSAREF
          documentation. You can't use RSAREF in any commercial
          (moneymaking) manner of any type, nor can you use it to
          provide services of any kind to any other party. For
          information on commercial licenses of RSAREF-compatible
          products, please contact RSA Data Security. (Special
          arrangements are available for educational institutions and
          non-profit organizations.)

     2.   You can give others RSAREF and programs that interface to
          RSAREF, under the same terms and conditions as your RSAREF
          license.

     3.   You can modify RSAREF as required to port it to other
          operating systems and compilers, as long as you give a copy
          of the results to RSA Laboratories. Other changes require
          written consent.

     4.   You can't send RSAREF outside the United States or Canada, or
          give it to anyone who is not a U.S. or Canadian citizen and
          doesn't have a U.S. "green card." (These are U.S. State and
          Commerce Department requirements, because RSA and DES are
          export-controlled technologies.)


HOW TO GET IT

To obtain RSAREF, read the license at the end of the note and return a
copy of the following paragraph by electronic mail to
<rsaref-administrator@rsa.com>:

     I acknowledge that I have read the RSAREF Program License
     Agreement and understand and agree to be bound by its terms and
     conditions, including without limitation its restrictions on
     foreign reshipment of the Program and information related to the
     Program. The electronic mail address to which I am requesting
     that the program be transmitted is located in the United States
     of America or Canada and I am a United States citizen, a Canadian
     citizen, or a permanent resident of the United States. The RSAREF
     Program License Agreement is the complete and exclusive agreement
     between RSA Laboratories and me relating to the Program, and
     supersedes any proposal or prior agreement, oral or written, and
     any other communications between RSA Laboratories and me relating
     to the Program.

RSAREF is distributed by electronic mail in UNIX(TM) "uuencoded" TAR
format. When you receive it, store the contents of the message in a
file, and run your operating system's "uudecode" and TAR programs.
For example, suppose you store the contents of your message in the
file 'contents'. You would run the commands:

     uudecode contents             # produces rsaref.tar
     tar -xvf rsaref.tar

RSAREF includes about 60 files organized into the following
subdirectories:

     doc       documentation on RSAREF and RDEMO
     install   makefiles for various operating systems
     rdemo     RDEMO demonstration program
     source    RSAREF source code and include files
     test      test scripts for RDEMO

RSAREF is also available via anonymous FTP to 'rsa.com'. Along with
RSAREF you can get RIPEM, Mark Riordan's RSAREF-based privacy-enhanced
mail application, and an Emacs command interface to RIPEM. See the
file 'README' in the FTP directory 'rsaref' for more information.


USERS' GROUP

RSA Laboratories maintains the electronic-mail users' group
<rsaref-users@rsa.com> for discussion of RSAREF applications, bug
fixes, etc. To join the users' group, send electronic mail to
<rsaref-users-request@rsa.com>.


REGISTRATION

RSAREF users who register with RSA Laboratories are entitled to free
RSAREF upgrades and bug fixes as soon as they become available and a
50% discount on selected RSA Data Security products. To register,
send your name, address, and telephone number to
<rsaref-registration@rsa.com>.


INNOVATION PRIZES

RSA Laboratories will award cash prizes for the best applications
built on RSAREF. If you'd like to submit an application, want to be
on the review panel, or would like more details, please send
electronic mail to <rsaref-prizes@rsa.com>. Applications are due
December 31, 1992, and awards will be announced March 31, 1993. First
prize is $5000, second prize is $2000, and there are five prizes of
$1000.


PUBLIC-KEY CERTIFICATION

RSA Data Security offers public-key certification services conforming
to forthcoming PEM standards. For more information, please send
electronic mail to <pem-info@rsa.com>.


PKCS: PUBLIC-KEY CRYPTOGRAPHY STANDARDS

To obtain copies of RSA Laboratories' Public-Key Cryptography
Standards (PKCS), send electronic mail to <pkcs-info@rsa.com>.


OTHER QUESTIONS

If you have questions on RSAREF software, licenses, export
restrictions, or other RSA Laboratories offerings, send electronic
mail to <rsaref-administrator@rsa.com>.


AUTHORS

RSAREF was written by the staff of RSA Laboratories with assistance
from RSA Data Security's software engineers. The DES code is based on
an implementation that Justin Reyneri did at Stanford University. Jim
Hwang of Stanford wrote parts of the arithmetic code under contract
to RSA Laboratories.


ABOUT RSA LABORATORIES

RSA Laboratories is the research and development division of RSA Data
Security, Inc., the company founded by the inventors of the RSA
public-key cryptosystem. RSA Laboratories reviews, designs and
implements secure and efficient cryptosystems of all kinds. Its
clients include government agencies, telecommunications companies,
computer manufacturers, software developers, cable TV broadcasters,
interactive video manufacturers, and satellite broadcast companies,
among others.

RSA Laboratories draws upon the talents of the following people:

Len Adleman, distinguished associate - Ph.D., University of
  California, Berkeley; Henry Salvatori professor of computer
  science at University of Southern California; co-inventor of
  RSA public-key cryptosystem; co-founder of RSA Data Security, Inc.

Taher Elgamal, senior associate - Ph.D., Stanford University;
  director of engineering at RSA Data Security, Inc.; inventor of
  Elgamal public-key cryptosystem based on discrete logarithms

Martin Hellman, distinguished associate - Ph.D., Stanford University;
  professor of electrical engineering at Stanford University;
  co-inventor of public-key cryptography, exponential key exchange;
  IEEE fellow; IEEE Centennial Medal recipient

Burt Kaliski, chief scientist - Ph.D., MIT; former visiting assistant
  professor at Rochester Institute of Technology; author of Public-Key
  Cryptography Standards; general chair of CRYPTO '91

Cetin Koc, associate - Ph.D., University of California, Santa
  Barbara; assistant professor at University of Houston
 
Ron Rivest, distinguished associate - Ph.D., Stanford University;
  professor of computer science, MIT; co-inventor of RSA public-key
  cryptosystem; co-founder of RSA Data Security, Inc.; member of
  National Academy of Engineering; director of International
  Association for Cryptologic Research; program co-chair of ASIACRYPT
  '91

RSA Laboratories seeks the talents of other people as well. If you're
interested, please write or call.

ADDRESSES

RSA Laboratories                   RSA Data Security, Inc.
100 Marine Parkway                 100 Marine Parkway
Redwood City, CA  94065            Redwood City, CA  94065

(415) 595-7703                     (415) 595-8782
(415) 595-4126 (fax)               (415) 595-1873 (fax)

PKCS, RSAREF and RSA Laboratories are trademarks of RSA Data
Security, Inc. All other company names and trademarks are not.

----------------------------------------------------------------------
                           RSA LABORATORIES
                      PROGRAM LICENSE AGREEMENT


RSA LABORATORIES, A DIVISION OF RSA DATA SECURITY, INC. ("RSA")
GRANTS YOU A LICENSE AS FOLLOWS TO THE "RSAREF" PROGRAM:

1.   LICENSE. RSA grants you a non-exclusive, non-transferable,
     perpetual (subject to the conditions of section 8) license
     for the "RSAREF" program (the "Program") and its associated
     documentation, subject to all of the following terms and
     conditions:

     a.   to use the Program on any computer in your possession;

     b.   to make copies of the Program for back-up purposes;

     c.   to modify the Program in any manner for porting or
          performance improvement purposes (subject to Section 2)
          or to incorporate the  Program into other computer programs 
          for your own personal or internal use, provided that you 
          provide RSA with a copy  of any such modification or 
          Application Program by electronic mail, and grant RSA 
          a perpetual, royalty-free license to use and distribute 
          such modifications and Application Programs on the terms 
          set forth in this Agreement.

     d.   to copy and distribute the Program and Application Programs
          in accordance with the limitations set forth in Section 2.

"Application Programs" are programs which incorporate all or any
portion of the Program in any form. The restrictions imposed on
Application Programs in this Agreement shall not apply to any software
which, through the mere aggregation on distribution media, is
co-located or stored with the Program.

2.   LIMITATIONS ON LICENSE.

     a.   RSA owns the Program and its associated documentation and
          all copyrights therein. You may only use, copy, modify and
          distribute the Program as expressly provided for in this
          Agreement. You must reproduce and include this Agreement,
          RSA's copyright notices and disclaimer of warranty on any
          copy and its associated documentation.

     b.   The Program and all Application Programs are to be used only
          for non-commercial purposes. However, media costs associated
          with the distribution of the Program or Application Programs
          may be recovered.

     c.   The Program, if modified, must carry prominent notices
          stating that changes have been made, and the dates of any
          such changes. 

     d.   Prior permission from RSA is required for
          any modifications that access the Program through ways
          other than the published Program interface or for 
          modifications to the Program interface. RSA will grant
          all reasonable requests for permission to make such
          modifications.

3.   NO RSA OBLIGATION. You are solely responsible for all of your
     costs and expenses incurred in connection with the distribution
     of the Program or any Application Program hereunder, and RSA
     shall have no liability, obligation or responsibility therefor.
     RSA shall have no obligation to provide maintenance, support,
     upgrades or new releases to you or to any distributee of the
     Program or any Application Program.

4.   NO WARRANTY OF PERFORMANCE. THE PROGRAM AND ITS ASSOCIATED
     DOCUMENTATION ARE LICENSED "AS IS" WITHOUT WARRANTY AS TO THEIR
     PERFORMANCE, MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR
     PURPOSE. THE ENTIRE RISK AS TO THE RESULTS AND PERFORMANCE OF
     THE PROGRAM IS ASSUMED BY YOU AND YOUR DISTRIBUTEES. SHOULD THE
     PROGRAM PROVE DEFECTIVE, YOU AND YOUR DISTRIBUTEES (AND NOT RSA)
     ASSUME THE ENTIRE COST OF ALL NECESSARY SERVICING, REPAIR OR
     CORRECTION.

5.   LIMITATION OF LIABILITY. EXCEPT AS EXPRESSLY PROVIDED FOR IN
     SECTION 6 HEREINUNDER, NEITHER RSA NOR ANY OTHER PERSON WHO HAS
     BEEN INVOLVED IN THE CREATION, PRODUCTION, OR DELIVERY OF THE
     PROGRAM SHALL BE LIABLE TO YOU OR TO ANY OTHER PERSON FOR ANY
     DIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF RSA HAS BEEN
     ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

6.   PATENT INFRINGEMENT OBLIGATION. Subject to the limitations set
     forth below, RSA, at its own expense, shall: (i) defend, or at
     its option settle, any claim, suit or proceeding against you on
     the basis of infringement of any United States patent in the
     field of cryptography by the unmodified Program; and (ii) pay
     any final judgment or settlement entered against you on such
     issue in any such suit or proceeding defended by RSA. The
     obligations of RSA under this Section 6 are subject to: 
     (i) RSA's having sole control of the defense of any such claim, 
     suit or proceeding; (ii) your notifying RSA promptly in writing
     of each such claim, suit or  proceeding and giving RSA authority
     to proceed as stated in this  Section 6; and (iii) your giving 
     RSA all information known to you relating to such claim, 
     suit or proceeding and cooperating  with RSA to defend any such 
     claim, suit or proceeding. RSA shall have no obligation under 
     this Section 6 with respect to any claim to the extent it is 
     based upon (A) use of the Program  as modified by any person 
     other than RSA or use of any Application Program, where use 
     of the unmodified Program would not constitute an infringement, 
     or (B) use of the Program in a manner other than that permitted 
     by this Agreement.  THIS SECTION 6 SETS FORTH RSA'S ENTIRE 
     OBLIGATION AND YOUR EXCLUSIVE REMEDIES CONCERNING CLAIMS FOR  
     PROPRIETARY RIGHTS INFRINGEMENT.

     NOTE: Portions of the Program practice methods described in and
     subject to U.S. Patents Nos. 4,200,770, 4,218,582 and 4,405,829,
     and all foreign counterparts and equivalents, issued to Leland
     Stanford Jr. University and to Massachusetts Institute of
     Technology. Such patents are licensed to RSA by Public Key
     Partners of Sunnyvale, California, the holder of exclusive
     licensing rights. This Agreement does not grant or convey any
     interest whatsoever in such patents.

7.   RSAREF is a non-commercial publication of cryptographic
     techniques. Portions of RSAREF have been published in the
     International Security Handbook and the August 1992 issue of Dr.
     Dobb's Journal. Privacy applications developed with RSAREF may be
     subject to export controls. If you are located in the United States
     and develop such applications, you are advised to consult with the
     State Department's Office of Defense Trade Controls.

8.   TERM. The license granted hereunder is effective until
     terminated. You may terminate it at anytime by destroying
     the Program and its associated documentation. The termination
     of your license will not result in the termination of the
     licenses of any distributees who have received rights to the
     Program through you so long as they are in compliance with
     the provisions of this license.

9.   GENERAL

     a.   This Agreement shall be governed by the laws of the State of
          California.

     b.   Address all correspondence regarding this license to RSA's
          electronic mail address <rsaref-administrator@rsa.com>, or
          to

               RSA Laboratories
               ATTN: RSAREF Administrator
               100 Marine Parkway, Suite 500
               Redwood City, CA  94065
