M ASTER  S OFTWARE QUALITY SOFTWARE SINCE 1958

          1. CHOOSING A CRYPTOGRAPHIC PRODUCT



               Master Software offers six separate cryptographic products.
          All of them are strong, all of them are reliable, all are easy to
          use, all of them are well-suited to their tasks.  How do you
          choose?


          TABLE OF CONTENTS

          1. CHOOSING A CRYPTOGRAPHIC PRODUCT
            1.1. Messages and Files
            1.2. Distributed Keys
            1.3. No Distributed Keys
            1.4. Authentication
            1.5. Time-Proven Methods
            1.6. Less Typing, Less Memorization



          1.1. Messages and Files


               The first question is, what are you trying to protect?  Are
          you protecting files on a single computer or within a local
          network, or are you protecting messages which will be sent over
          public networks such as the Internet?

               If you need to protect files on your computer, then GK-Crypt
          is the right choice.  It is easy to use, reasonably fast, and
          extremely secure.  In fact, it is the strongest file encryption
          product available outside of the military.  It is stronger than
          many of the encryption products used by foreign governments, and
          far stronger than the encryption used by banks, credit card
          companies, brokerages and similar businesses.

               If, on the other hand, you need to protect messages, we
          offer a choice of three products, MX-Crypt, NK-Crypt and
          OP-Crypt.  The one you choose depends on your setup.



          1.2. Distributed Keys


               If the people or groups who need to communicate secretly are
          already in contact, already known to one another, then OP-Crypt
          is the logical choice.  This is especially true if you already
          have a communications network set up, and you already have an
          established method for distributing secret encryption keys.

               OP-Crypt is the only cryptographic product, from any source,
          which can be considered absolutely secure.  It uses the renowned
          One-Time Pad encryption algorithm, the only algorithm that has
          ever been proven to be unbreakable.  Provided that the keys are
          never revealed, your messages will remain secure and unbreakable
          forever.

               OP-Crypt is fast and easy to use.  Its great advantage over
          all of the competing products is that there is no need to
          distribute keys for each message.  The OP-Crypt package generates
          long, secure message keys.  Only the secret network key and
          station keys need to be distributed, which needs to be done only
          once for each station.



          1.3. No Distributed Keys


               If you need to protect messages, but you do not know
          beforehand who will be communicating, if you do not have a method
          for distributing keys, if people frequently join your network
          with no previous contact with your network hub, or if you expect
          that people already in the field may need to communicate directly
          with each other, then MX-Crypt and NK-Crypt are your best
          choices.  In fact, they are your only choices.  There are no
          other products available anywhere that can establish secure
          communications without any exchange of keys.

               NK-Crypt is based on large prime numbers.  This is a
          technology that has stood the test of time.  (The patent for the
          algorithm underlying NK-Crypt expired in 1993.)  Hundreds of
          mathematicians have tried and failed to break it.  However, it is
          slow, and unsuited for sending long messages or large files.

               MX-Crypt offers the advantage of speed.  MX-Crypt is 2200
          times as fast as NK-Crypt.

               MX-Crypt is based on our exclusive matrix technology.  This
          method is so new and revolutionary that Master Software has been
          granted four US patents on our matrix encryption algorithms.
          Master Software has full confidence in the strength of these
          methods.  We have performed extensive analysis of potential
          attacks.  Over time we expect users of the old NK-Crypt to
          migrate to the newer, speedier MX-Crypt.



          1.4. Authentication


               When encryption is used to protect communications, there are
          two types of threats, passive threats and active threats.  The
          typical passive threat is wire-tapping, where an opponent obtains
          your messages, but does not add, delete or change your messages.
          All of Master Software's message encryption products provide
          strong security against these passive threats.  Normally, an
          eavesdropper will not change your message traffic, in order to
          stay undetected.

               The typical active threat is impersonation, where an
          opponent poses as a legitimate user in order to receive messages
          or to send bogus messages.  When there is a danger of
          impersonation, the legitimate users need to use message
          authentication in order to assure that they are communicating
          only with other authorized users.

               NK-Crypt provides a customized version where the users of
          the customized version can communicate only with users having
          that same version.  Users of the standard version, or users of a
          different customized version, cannot communicate with the users
          of your customized version.

               Master Software provides secure distribution of these
          customized versions.  User groups can set up any desired
          arrangement so that only authorized users can purchase a given
          customized version.  Each customized version has a name, and the
          organization can choose to have a password which must be provided
          by anyone ordering their custom version.  Other identifying
          methods can also be used.  For example, an organization could
          require that orders for their customized version be placed only
          on the company letterhead, and paid by company checks.

               Nonetheless, some organizations may not wish Master Software
          to have access to their customized version.

               MX-Crypt provides authentication in a different way.
          MX-Crypt allows users to choose their own secret authentication
          key, unknown to anyone else.  Any group that wishes to provide
          message authentication this way should use MX-Crypt.  It is the
          users' responsibility to distribute their authentication key only
          to their authorized network users.



          1.5. Time-Proven Methods


               Users who demand time-proven security can use any of
          GK-Crypt, OP-Crypt and NK-Crypt with full confidence.  They are
          designed using cryptographic techniques that have proven reliable
          over decades, even centuries of use.

               Users who want the latest cutting-edge products may choose
          GK-Crypt and NS-Crypt.  NS-Crypt uses an entirely new technology
          for which four US patents have been granted.  GK-Crypt uses
          standard cryptographic methods combined in a powerful innovative
          way where they strengthen and reinforce each other to repel every
          known type of attack.



          1.6. Less Typing, Less Memorization


               All of these formidable cryptographic techniques have been
          built into program packages designed for ease of use.  The most
          important factor is that users do not need to memorize and type
          large numbers of keys.  All of the products have Master Keys
          which must be entered when the package is started.  For GK-Crypt,
          NK-Crypt and MX-Crypt the Master Key is the only key that ever
          needs to be typed.

               OP-Crypt, however has a network key, which is typed once
          when the software is installed, and station keys which need to be
          securely distributed, and typed when new stations join the
          network.  Thus, for actively growing networks, OP-Crypt requires
          ongoing key maintenance.