rfc1898.txt

来自「RFC 的详细文档！」· 文本 代码 · 共 1,600 行 · 第 1/5 页

Network Working Group                                    D. Eastlake 3rd
Request for Comments: 1898                                     CyberCash
Category: Informational                                        B. Boesch
                                                               CyberCash
                                                              S. Crocker
                                                               CyberCash
                                                                M. Yesil
                                                               CyberCash
                                                           February 1996


               CyberCash Credit Card Protocol Version 0.8

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   CyberCash is developing a general payments system for use over the
   Internet.  The structure and communications protocols of version 0.8
   are described.  This version includes credit card payments only.
   Additional capabilities are planned for future versions.

   This document covers only the current CyberCash system which is one
   of the few operational systems in the rapidly evolving area of
   Internet payments. CyberCash is committed to the further development
   of its system and to cooperation with the Internet Engineering Task
   Force and other standards organizations.

Acknowledgements

   The significant contributions of the following persons (in alphabetic
   order) to this protocol are gratefully acknowledged:

        Bruce Binder, Judith Grass, Alden Hart, Steve Kiser, Steve
        Klebe, Garry Knox, Tom Lee, Bob Lindenberg, Jim Lum, Bill
        Melton, Denise Paredes, Prasad Chintamaneni, Fred Silverman,
        Bruce Wilson, Garland Wong, Wei Wu, Mark Zalewski.

   In addition, Jeff Stapleton and Peter Wagner made useful comments on
   the first version of this memo.







Eastlake, et al              Informational                      [Page 1]

RFC 1898                 CyberCash Version 0.8             February 1996


History

   For historic purposes, it should be noted that this document was
   first posted as an Internet draft, and thus made publicly available,
   on 8 July 1995.

Table of Contents

      1. Overall System..........................................3
      1.1 System Overview........................................3
      1.2 Security Approach......................................5
      1.2.1 Authentication and Persona Identity..................5
      1.2.2 Privacy..............................................6
      1.3 Credit Card Operation..................................6
      2. General Message Wrapper Format..........................7
      2.1 Message Format.........................................7
      2.2 Details of Format......................................8
      2.3 Body Parts.............................................8
      2.4 Transparent Part.......................................9
      2.5 Opaque Part...........................................10
      2.6 Trailer...............................................10
      2.7 Example Messages......................................11
      3. Signatures and Hashes..................................12
      3.1 Digital Signatures....................................12
      3.2 Hash Codes............................................13
      4. Specific Message Formats...............................13
      4.1 Persona Registration and Application Retrieval........14
      4.1.1 R1 - registration...................................14
      4.1.2 R2 - registration-response..........................15
      4.1.3 GA1 - get-application...............................16
      4.1.4 GA2 - get-application-response......................17
      4.2 Binding Credit Cards..................................18
      4.2.1 BC1 - bind-credit-card..............................18
      4.2.2 BC4 - bind-credit-card-response.....................20
      4.3 Customer Credit Card Purchasing Messages..............21
      4.3.1 PR1 - payment-request...............................21
      4.3.2 CH1 - credit-card-payment...........................23
      4.3.3 CH2 - charge-card-response..........................24
      4.4 Merchant Credit Card Purchasing Messages..............25
      4.4.1 CM1 - auth-only.....................................26
      4.4.2 CM2 - auth-capture..................................28
      3.4.3 CM3 - post-auth-capture.............................28
      4.4.4 CM4 - void..........................................30
      4.4.5 CM5 - return........................................32
      4.4.6 CM6 - charge-action-response........................32
      4.4.7 The MM* Message Series..............................34
      4.4.8 CD1 - card-data-request.............................35
      4.4.9 CD2 - card-data-response............................37



Eastlake, et al              Informational                      [Page 2]

RFC 1898                 CyberCash Version 0.8             February 1996


      4.5 Utility and Error Messges.............................38
      4.5.1 P1 - ping...........................................39
      4.5.2 P2 - ping-response..................................39
      4.5.3 TQ1 - transaction-query.............................40
      4.5.4 TQ2 - transaction-cancel............................41
      4.5.5 TQ3 - transaction-response..........................42
      4.5.6 UNK1 - unknown-error................................44
      4.5.7 DL1 - diagnostic-log................................46
      4.5.8 DL2 - merchant-diagnostic-log.......................47
      4.6 Table of Messages Described...........................48
      5. Future Development.....................................49
      5.1 The Credit Card Authorization/Clearance Process.......49
      5.2 Lessons Learned.......................................50
      6. Security Considerations................................51
      References................................................51
      Authors' Addresses........................................52

1. Overall System

   CyberCash, Inc. of Reston, Virginia was founded in August of 1994 to
   partner with financial institutions and providers of goods and
   services to deliver a safe, convenient and inexpensive system for
   making payments on the Internet.  The CyberCash approach is based on
   establishing a trusted link between the new world of cyberspace and
   the traditional banking world.  CyberCash serves as a conduit through
   which payments can be transported quickly, easily and safely between
   buyers, sellers and their banks.  Significantly - much as it is the
   real world of commerce - the buyer and seller need not have any prior
   existing relationship.

   As a neutral third party whose sole concern is ensuring the delivery
   of payments from one party to another, CyberCash is the linchpin in
   delivering spontaneous consumer electronic commerce on the Internet.

1.1 System Overview

   The CyberCash system will provide several separate payment services
   on the Internet including credit card and electronic cash.  To gain
   access to CyberCash services, consumers need only a personal computer
   with a network connection.  Similarly, merchants and banks need make
   only minimal changes to their current operating procedures in order
   to process CyberCash transactions, enabling them to more quickly
   integrate safe on-line payments into their existing service
   offerings.  Communications with banks are over existing financial
   communications networks.






Eastlake, et al              Informational                      [Page 3]

RFC 1898                 CyberCash Version 0.8             February 1996


   To get started, consumers download free software from CyberCash on
   the Internet.  This software establishes the electronic link between
   consumers, merchants and their banks as well as between individuals.
   To make gaining access to the CyberCash system even easier, CyberCash
   "PAY" buttons may be incorporated into popular on-line service and
   software graphical user interfaces so that consumers using these
   products can easily enter the CyberCash system when they are ready to
   make payments for goods and services.  Consumers need not have any
   prior relationship with CyberCash to use the CyberCash system.  They
   can easily set up their CyberCash persona on-line.

   Transactions are automated in that once the consumer enters
   appropriate information into his own computer, no manual steps are
   required to process authorization or clearance transactions through
   the entire system.  The consumer need only initiate payment for each
   transaction by exercising the pay option on an electronic form.
   Transactions are safe in that they are cryptographicly protected from
   tampering and modification by eavesdroppers. And they are private in
   that information about the consumer not relevant to the transaction
   is not visible to the merchant.

      +------------+            +------------+
      |            |            |            |
      |  Internet  |            |  Internet  |
      |  customer  +------------+  merchant  +
      |            |            |  /         |
      +------------+            +------------+
                                /
                               /
                   +------------|-+
                   | CyberCash  | |
                   |     server | |
                   +-----+------|-+
                         |      |
                         |      |
          +--------------+------|---------+
          | +--------+       +--+-------+ |
          | | card   +-------+ / charge | |
          | | issuer |       | acquirer | |
          | +--------+       +----------+ |
          |                               |
          |      The Banking System       |
          +-------------------------------+

                   SYSTEM OVERVIEW






Eastlake, et al              Informational                      [Page 4]

RFC 1898                 CyberCash Version 0.8             February 1996


1.2 Security Approach

   The CyberCash system pays special attention to security issues.  It
   uses encryption technology from the world's leading sources of
   security technology and is committed over time to employing new
   security technologies as they emerge.

1.2.1 Authentication and Persona Identity

   Authentication of messages is based on Public Key encryption as
   developed by RSA.  The CyberCash Server maintains records of the
   public key associated with every customer and merchant persona.  It
   is thus able to authenticate any information digitally signed by a
   customer or merchant regardless of the path the data followed on its
   way to the server.  The corresponding private key, which is needed to
   create such digital signatures, will be held by the customer or
   merchant and never revealed to other parties.  In customer software,
   the private key is only stored in an encrypted form protected by a
   passphrase.

   While the true CyberCash identity of a customer or merchant is
   recognized by their public/private key pair, such keys are too
   cumbersome (over 100 hex digits) to be remembered or typed by people.
   So, the user interface utilizes short alphanumeric ID's selected by
   the user or merchant for purposes of specifying a persona.  CyberCash
   adds check digits to the requested ID to minimize the chance of
   accidental wrong persona selection.  Persona IDUs are essentially
   public information.  Possession of an persona ID without the
   corresponding private key is of no benefit in the current system.

   Individuals or organizations may establish one or more CyberCash
   customer personas directly with CyberCash.  Thus, an individual may
   have several unrelated CyberCash personas or share a CyberCash
   persona with other individuals.  This approach provides a degree of
   privacy consistent with Internet presence generally and with cash
   transactions specifically.  However, persona holders who wish to use
   a credit card for purchases in conjunction with their CyberCash
   persona must first meet such on-line identification criteria as the
   card issuing organization requires.

   Control over a CyberCash persona is normally available only to an
   entity that possesses the private key for that persona.  However, a
   special provision is made to associate an emergency close out
   passphrase with a CyberCash persona.  On receipt of the emergency
   close out passphrase, even if received over insecure channels such as
   a telephone call or ordinary email, CyberCash will suspend activity
   for the CyberCash persona.  This emergency close-out passphrase can
   be stored separately from and with somewhat less security than the



Eastlake, et al              Informational                      [Page 5]

RFC 1898                 CyberCash Version 0.8             February 1996


   private key for the persona since the emergency passphrase can not be
   used to divert funds to others. This provides some protection against
   loss or misappropriation of the private key or the passphrase under
   which the private key in kept encrypted.  In the cash system, the
   emergency close-out passpharase may also transfer the persona balance
   to a designated bank account.

1.2.2 Privacy

   Encryption of messages use the Digital Encryption Standard (DES),
   commonly used in electronic payment systems today.  It is planned to
   superencrypt (i.e., encrypted more than one level) particularly
   sensitive information, such as PIN numbers, and handle them so that
   the plain text readable version never exists in the CyberCash system
   except momentarily, within special purpose secure cryptographic
   hardware that is part of the server, before being re-encrypted under
   another key.

   The processing of card charges through the CyberCash system is
   organized so that the merchant never learns the customerUs credit
   card number unless the merchantUs bank chooses to release this
   information to the merchant or it is required for dispute resolution.
   In addition, the server maintains no permanent storage of card
   numbers.  They are only present while a transaction involving that
   card is in progress.  These practices greatly reduce the chance of
   card number misappropriation.

1.3 Credit Card Operation

   Using the CyberCash system for credit card transactions, once price
   has been negotiated and the consumer is ready to purchase, the
   consumer simply clicks on the CyberCash "PAY" button displayed on the
   merchant interface, which invokes the merchant CyberCash software.
   The merchant sends the consumer an on-line invoice that includes