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.

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

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.

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

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

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
relevant purchase information which appears on the customerUs screen.
(See PR1 message.) The consumer adds his credit card number and
other information by simply selecting from a list of credit cards he
has registered to his CyberCash persona. All this information is
digitally signed by the customer's CyberCash software, encrypted, and
passed, along with a hash code of the invoice as seen by the
customer, to the merchant. (See CH1 message.)

Upon receipt, the merchant adds additional authorization information
which is then encrypted, electronically signed by the merchant, and
sent to the CyberCash Server. (See CM1 & CM2 messages.) The
CyberCash Server can authenticate all the signatures and be sure that
the customer and merchant agree on the invoice and charge amount.
The CyberCash Server then forwards the relevant information to the

acquiring bank along with a request on behalf of the merchant for a
specific banking operation such as charge authorization. The bank
decrypts and then processes the received data as it would normally
process a credit card transaction. The bank's response is returned
to the CyberCash Server which returns an electronic receipt to the
merchant (see CM6 message) part of which the merchant is expected to
forward to the customer (see CH2 message). The transaction is
complete.

2. General Message Wrapper Format

Version 0.8 of the external format for the encoding of CyberCash
messages is described below. CyberCash messages are stylized
documents for the transmission of financial data over the Internet.

While there are numerous schemes for sending information over the
Internet (HTTP, SMTP, and others), each is attached to a specific
transmission mechanism. Because CyberCash messages will need to
travel over each of these media (as well as others) a transmission
independent mechanism is needed.

2.1 Message Format

CyberCash messages consist of the following components:

1. Header - defines the start of the CyberCash message and includes
version information.

2. Transparent Part - contains information that is not private.

3. Opaque Part(s) - contains the financial information in the
message and is both privacy protected as well as tamper protected.
An opaque part is not present in some messages. When present, the
opaque part usually provides tamper protection for the transparent
part.

4. Trailer - defines the end of the CyberCash message and includes a
check value to enable the receiver to determine that the message
has arrived undamaged. Note: this check value is intended only to
detect accidental damage to the message, not deliberate tampering.

No null characters (zero value) or characters with the eighth bit
on are permitted inside a CyberCash message. "Binary" quantities
that might have such byte values in them are encoded in base64 as
described in RFC1521.

2.2 Details of Format

The header consists of a single line which looks approximately like
this

$$-CyberCash-0.8-$$

or like this

$$-CyberCash-1.2.3-Extra-$$

It includes a number of fields separated with the minus character "-"

1. "$$" - the literal string with the initial $ in column 1.

2. "CyberCash" - the literal string (case insensitive)

3. x.y or x.y.z - the version number of the message format. x is the
primary version number. y is a subversion number. z, if present, is
a subsubversion number.

4. "Extra" - an optional additional alphanumeric string.

5. "$$" - the literal string

Version numbers start at 0.7 and count up. The ".z" is omitted when
z is zero. 0.7 and 0.8 are the test and initial shipped version of
the credit card system. 0.9 and 1.0 are expected to also incorporate
the test and initial shipped versions of the cash facilities as well
as improvements to the credit card system.

The "Extra" string is used within secure environments so that one
subcomponent can scribble a note to another with minimum overhead.
For example, a server firewall could put "HTTP" or "SMTP" here before
forwarding the message to the core server within the firewall
perimeter.

2.3 Body Parts

The body parts of the message (both transparent and opaque) consist
of attribute value pairs in formats that are reminiscent of the
standard electronic mail header (RFC822) format. However, there are
some differences.

Attribute names start with and are composed predominantly of letters
and internal hyphens except that they sometimes end with a hyphen
followed by a number. Such a trailing number is used when there is
logically an indexed vector of values. Attribute names are

frequently referred to as labels.

If the label ends with a ":", then RFC822 processing is done. While
the existence of trailing white space is significant, all leading
white space on continuation lines is stripped. Such lines are
wrapped at 64 characters in length, excluding any line termination
character(s).

However, if the label is terminated with a ";", this indicates a
free-form field where new-line characters and any leading white
space, after the initial space that indicates a continuation line, is
significant. Such lines should not be wrapped except that, to avoid
other processing problems, they are forcibly wrapped at 200
characters.

Blank lines are ignored and do not signify a change to a different
mode of line handling.

Another way of looking at the above is as follows: after having found
an initial $$ start line, you can treat any following lines according
to the first character. If it is alphanumeric, it is a new label
which should be terminated with a ":" or ";" and indicates a new
label-value pair. If it is a white space character, it indicates the
continuation of the value for the preceding new label line. (Exactly
how the continuation is processed depends on the label termination
character.) If it is "$", it should be the end line for the message.
If it is #, it is a comment line and should be ignored. Other
initial characters are undefined. (As of this date, no software
sends CyberCash messages with # lines but they are convenient for
commenting messages stored in files.)

2.4 Transparent Part

The transparent part includes any clear-text data associated with the
financial transaction as well as information needed by CyberCash and
others to decrypt the opaque part(s). It always includes a
transaction field which is the transaction number generated by the
requester and which is repeated in the response. It always includes
a date field that is the local date and time at the requester and is
repeated in the response. In all cases other than an initial
registration to establish a persona ID, it includes the requester's
persona ID.

On messages bound for the server, there is a "cyberkey:" field that
identifies which server public key was used to encrypt the session
key.

2.5 Opaque Part

The opaque part consists of a single block of characters encoded
using base64 encoding (see RFC1521). The data in the opaque section
is always encrypted before encoding.

The label "opaque" or "merchant-opaque" precedes the opaque part
depending on whether the data was encrypted by the client or merchant
software.

On messages inbound to the server, the data to be opaqued is DES CBC
encrypted under a random transacton key and then that DES key is RSA
encrypted under one of the server's public keys. The RSA encrypted
DES key appears as the first part of the base64 encoded field and is
not broken out as a separate value in the message. The corresponding
outbound reply from the server can simply be DES encrypted under this
transaction key as there is enough plain text information to identify
the transaction and the customer or merchant will have remembered the
transaction key from the inbound message.

A signature is not generally necessary in the opaque part of a reply
message. Knowledge of the transaction key is adequate
authentication. In order for someone to forge the response, they
would have to know the server's private key to be able to get at the
transaction key. It is assumed that if anyone tampered with the
response opaque part, the probability that it would decrypt to
something that would parse is insignificant. (Just the fact that the
8th bit has to be off means a chance of 1 in 2**n where there are n
characters and that's ignoring the rest of the formatting.) While
someone can tamper with the transparent part, this usually either has
no effect or means that the client won't find the transaction key, in
which case it's just a particular example of denial of service by
damaging a message.

2.6 Trailer

The trailer is intended to close the message and provide a definitive
and parseable end of the message.

The trailer consists of several fields separated by "-" as in header.

1. "$$" - literal string.

2. "CyberCash" - literal string (case insensitive).

3. "End" - literal string (case insensitive).

4. transmission checksum.

5. "$$" - literal string.

The transmission checksum is the MD5 has of all printable characters
in the version number in the start line and those appearing after the
second $$ of the start line and before the first $$ of the trailer
line as transmitted. Note that all white space is left out of this
hash, including any new-lines, spaces, tabs, carriage returns, etc.
The exact label terminators actually used (: or ;) are included as
would any # comment line. Note that the optional "Extra" string in
the $ start line is not included. The idea is to check correct
transmission while avoiding sensitivity to gateways or processing
that might change the line terminator sequence, convert tabs to
spaces, or the like.

2.7 Example Messages

Simple message from a client:

$$-CyberCash-0.8-$$
id: DONALD-69
transaction: 918273645
date: 199512250102
cyberkey:CC1001
opaque:
GpOJvDpLH62z+eZlbVkhZJXtTneZH32Qj4T4IwJqv6kjAeMRZw6nR4f0OhvBTFfPm+GG
aXmoxyUlwVnFkYcOyTbSOidqrwOjnAwLEVGJ/wa4ciKKI2PsNPA4sThpV2leFp2Vmkm4
elmZdS0Qe350g6OPrkC7TKpQQKHjzczRRytWbFvE+zSi44wMF/ngzmiVsUCW01FXc8T9
EB8KjHEzVSRfZDn+lP/c1nTLTwPrQ0DYiN1lGy9nwM1ImXifijHR19LZIHlRXy8=
$$-End-CyberCash-End-jkn38fD3+/DFDF3434mn10==-$$

Message from a merchant:

$$-CyberCash-a.b.c-extra-$$
merchant-ccid: acme-69
merchant-date: 19951231115959
merchant-transaction: 987654321
label: value

labelx: multiple line
value...
# comment
# another comment line
label; text with a real
multi-line
format !
merchant-cyberkey: CC1001
merchant-opaque:

C1Q96lU7n9snKN5nv+1SWpDZumJPJY+QNXGAm3SPgB/dlXlTDHwYJ4HDWKZMat+VIJ8y
/iomz6/+LgX+Dn0smoAge7W+ESJ6d6Ge3kRAQKVCSpbOVLXF6E7mshlyXgQYmtwIVN2J
66fJMQpo31ErrdPVdtq6MufynN8rJyJtu8xSNolXlqIYNQy5G2I3XCc6D3UnSErPx1VJ
6cbwjLuIHHv58Nk+xxt/FyW7yAMwUb9YNcmOj//6Ru0NiOA9P/IiWczDe2mJRK1uqVpC
sDrWehG/UbFTPD26trlYRnnY
$$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$

3. Signatures and Hashes

Inbound CyberCash request messages normally have a signature, as
described below, of all of the messages fields outside of the
signature. This signature is transmitted inside the opaque part of
the message. It enables the server to authenticate the source of the
message.

Messages from a merchant to a client initiating a purchase sequence
have fields signed by the merchant. These fields and this signature
are included by the client in the opaque part of their card purchase
message to the merchant so that, when all is passed on to the server,
it can verify that the client saw the information the merchant
intended.

More information on CyberCash signatures and the hash codes they are
based on, is given below.

3.1 Digital Signatures

Digital signatures are a means of authenticating information. In
CyberCash messages, they are calculated by first taking the hash of
the data to be authenticated, as described below, and then encoding
the hash using an RSA private key.

Anyone possessing the corresponding public key can then decrypt the
hash and compare it with the message hash. If they match, then you
can be sure that the signature was generated by someone possessing
the private key which corresponded with the public key you used and
that the message was not tampered with.

In the CyberCash system, clients, merchants, and the server have
public-private key pairs. By keeping the private key secret and
registering their public key with the server (for a merchant or
client) or publishing their public key or keys (for the server), they
can provide high quality authentication by signing parts of messages.

An RSA digital signature is approximately the size of the modulus
used. For example, if that is 768 bits long, then the binary digital
signature would be 768 bits or 96 bytes long and its base 64 encoding
would be 128 bytes.

3.2 Hash Codes

The hashes used in CyberCash messages are message digests. That is,
a non-invertable fingerprint of a message such that it is
computationally infeasible to find an alternate message with the same
hash. Thus the relatively small hash can be used to secure a larger
message. If you are confident in the authenticity of the hash and
are presented with a message which matches the hash, you can be sure
it is the original message, at least as regards all ASPects that have
been included in the hash.

The hash is calculated using the MD5 algorithm (see RFC1321) on a
synthetic message. The synthetic message is composed of the labels
and values specified in a list for the particular hash. Since the
hash is input order dependent, it is essential that the label-value
pairs be assembled in the order specified. In some cases, a range of
matching labels is specified. For example, "card*" to match card-
number, card-expiration-date, and all other labels starting with
"card". In such cases, all existing matching labels are used in
ascending alphabetic order by ASCII character code.

If a label is specified in a signature list but is not present in the
label-value data on which the hash is being calculated, it is not
included in the hash at all. That is, even the label and label
terminator are omitted from the synthetic message.

Before being hashed, the text of the synthetic message is processed
to remove all "white space" characters. White space characters are
defined as any with an ASCII value of 32 (space) or less or 127
(rubout) or greater. Thus all forms of new-line/carriage-return and
distinctions such as blank lines, trailing spaces, replacement of a
horizontal tab character by multiple spaces, etc., are ignored for
hash purposes.

MD5 hashes are 16 bytes long. This means that the base 64 encoding
of such a hash will be 24 characters (of which the last two will
always be padding equal signs).

4. Specific Message Formats

This section describes the formats of the Verison 0.8 CyberCash
messages by example with comments. The reader in assumed to be
familiar with terms such as "acquirer", "PAN" (primary account
number), etc., defined in ISO 8583, and currency designations as
defined in ISO 4217. A few fields not relevant to current operations
have been removed to simplify this exposition.

In the following example messages, signatures, hashes, and encrypted
sections are fake nonsense text and ids are fictitious.

4.1 Persona Registration and Application Retrieval

The first step in customer use of CyberCash is registering a persona
using the customer application. This is done with the R1 message
defined below. The CyberCash server responds with the R2 message.

When the customer application learns that it is out of date, it can
use the GA1 request message to the server and its GA2 response to
download a new signed version of itself.

4.1.1 R1 - registration

Description: This is the initial message sent to create a new
CyberCash persona.

#####################################################################
Sender: CyberApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
transaction: 123123213
date: 19950121100505.nnn
cyberkey: CC1001
opaque:
FrYOQrD16lEfrvkrqGWkajM1IZOsLbcouB43A4HzIpV3/EBQM5WzkRJGzYPM1r3noBUc
MJ4zvpG0xlroY1de6DccwO9j/0aAZgDi9bcQWV4PFLjsN604j3qxWdYn9evIGQGbqGjF
vn1qI1Ckrz/4/eT1oRkBBILbrWsuwTltFd84plvTy+bo5WE3WnhVKsCUJAlkKpXMaX73
JRPoOEVQ3YEmhmD8itutafqvC90atX7ErkfUGDNqcB9iViRQ7HSvGDnKwaihRyfirkgN
+lhOg6xSEw2AmYlNiFL5d/Us9eNG8cZM5peTow==
$$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$

#####################################################################

Opaque Key: Generated using CyberCash encrypting public key
identified in CyberKey.

#####################################################################
Opaque Section Contents:

type: registration
swversion: 0.8win
content-language: en-us
requested-id: MyRequestedCCID

email: myemail@myemailhost.com
pubkey:
0VdP1eAUZRrqt3Rlg460Go/TTs4gZYZ+mvI7OlS3l08BVeoms8nELqL1RG1pVYdDrTsX
E5L+wcGCLEo5+XU5zTKkdRUnGRW4ratrqtcte7e94F+4gkCN06GlzM/Hux94
signature:
v6JGmxIwRiB6iXUK7XAIiHZRQsZwkbLV0L0OpVEvan9l59hVJ3nia/cZc/r5arkLIYEU
dw6Uj/R4Z7ZdqO/fZZHldpd9+XPaqNHw/y8Arih6VbwrO5pKerLQfuuPbIom

#####################################################################
signature is of the following fields: transaction, date, cyberkey,
type, swversion, content-language, requested-id, email, pubkey

#####################################################################
Explanation:
content-language is taken from the MIME header field (see RFC1766)
and is the language text messages should be generated in. (only
en-us implemented at this time.
swversion used to check if client application is old.

4.1.2 R2 - registration-response

Description: This message gives the success/failure response to R1.

#####################################################################
Sender: CyberServer
Receiver: CyberApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
transaction: 12312313
date: 19950121100505.nnn
opaque:
r1XfjSQt+KJYUVOGU60r7voFrm55A8fP5DjJZuPzWdPQjGBIu3B6Geya8AlJfHsW11u8
dIv1yQeeYj/+l9TD1dXW21/1cUDFFK++J2gUMVv8mX1Z6Mi4OU8AfsgoCliwSkWmjSOb
kE62sAlZTnw998cKzMFp70TSlI3PEBtvIfpLq5lDCNbWidX8vFZV0ENUmMQ9DTP3du9w
fsFGvz1mvtHLT/Gj8GNQRYKF4xiyx4HYzTkSMhgU5B/QDLPS/SawIJuR86b9X0mwsr0a
gbGTzECPJTiKkrhxxMG/eymptsVQSLqNaTCx6w==
$$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$

#####################################################################
Opaque Key: Same as session key for R1 for same Transaction and
connection (there may be no ID!).

#####################################################################
Opaque Section Contents:

type: registration-response
server-date: 19950121100506.nnn
requested-id: MyRequestedCCID
response-id: CyberCashHandle
email: myemail@myemailhost.com
response-code: success/failure/etc.
pubkey:
0VdP1eAUZRrqt3Rlg460Go/TTs4gZYZ+mvI7OlS3l08BVeoms8nELqL1RG1pVYdDrTsX
E5L+wcGCLEo5+XU5zTKkdRUnGRW4ratrqtcte7e94F+4gkCN06GlzM/Hux94
swseverity: fatal/warning [absent if ok]
swmessage; Tells CyberApp that it is obsolete. Display this
text to the user. [only present if SWSeverity present]
message;
Free text of the error/success condition.
This text is to be displayed to the person
by the CyberCash application...

In general this includes: duplicate-id, bad-signature,
or ill-formed-registration

#####################################################################
Signature is of the following fields: no-signature

#####################################################################
Explanation:
responseid is used to suggest a unique ID if the failure was due
to the requested ID being already in use... If the reason for
failure was not due to duplicate ID then this field may be
omitted.
responseid gives the actual ID with check characters appended if
success.
swseverity can warn user of old client application or indicate
failure due to old or known buggy version.

4.1.3 GA1 - get-application

Description: Used by CyberApp to get an updated version.

#####################################################################
Sender: CyberApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
transaction: 123123213
date: 19950121100505.nnn

cyberkey: CC1001
opaque:
VHMS611wGkUmR6bKoI+ODoSbl7L5PKtEo6aM88LCidqN+H/8B4xM3LxdwUiLn7rMPkZi
xOGb+5d1lRV7WeTp21QYlqJr8emc6FAnGd5c0csPmcnEpTFh9xZDJaStarxxmSEwm2mw
l2VjEUODH6321vjoMAOFQWn7ER0o
$$-CyberCash-End-0QXqLlNxrn4GNQPPk9AO1Q==-$$

#####################################################################
Opaque Key: Generated using CyberCash encrypting public key identified
in CyberKey.

#####################################################################
Opaque Section Contents:

type: get-application
swversion: 0.8win

#####################################################################
Signature is of the following fields: no signature

#####################################################################
Explanation:
There may not be a customer persona so there is no ID. There
may not be a customer public/private key pair so there is
no signature. The swversion is mandatory so the server can
tell what to return.

4.1.4 GA2 - get-application-response

Description: Return success and URL of up to date copy of CyberApp
or failure.

#####################################################################
Sender: CyberServer
Receiver: CyberApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
transaction: 12312313
date: 19950110102333.nnn
opaque:
EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb
nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV
4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs
rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo
QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==

$$-CyberCash-End-0QXqLlNxrn4GNQPPk9AO1Q==-$$

#####################################################################
Opaque Key: session key from GA1

#####################################################################
Opaque Section Contents:

type: get-application-response
server-date: 19950110102334.nnn
response-code: success/failure/etc.
message; Text message to be displayed to the user providing more
information on the success/failure.
swversion: 0.8win
application-url: http://foo.cybercash.com/server/0.8WIN.EXE
application-hash: lSLzs/vFQ0BXfU98LZNWhQ==

#####################################################################
Signature: none.

#####################################################################
Explanation:
application-hash is the MD5 of the binary of the application.
application-url & application-hash omitted on failure.
swversion is the version being transmitted to the customer.

4.2 Binding Credit Cards

The CyberCash system is design to give the card issuing organization
control over whether a card may be used via the CyberCash system.
The customer, after having registered a persona with CyberCash as
described above, can then bind each credit card they wish to use to
their CyberCash persona. This is done via the BC1 message from the
customer to their CyberCash server and the BC4 response from the
server.

4.2.1 BC1 - bind-credit-card

Description: This is the initial message in the process of binding a
credit card to a CyberCash persona.

#####################################################################
Sender: CyberApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
id: MyCyberCashID
date: 19950121100505.nnn
transaction: 12312314
cyberkey: CC1001
opaque:
EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb
nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV
4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs
rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo
QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==
$$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$

#####################################################################
Opaque Key: generated from CyberCash encryption key identified in
CyberKey

#####################################################################
Opaque Section Contents:

type: bind-credit-card
swversion: 0.8win
card-number: 1234567887654321
card-type: mastercard
card-salt: 46735210
card-expiration-date: 05/99
card-name: John Q. Public
card-street:
card-city:
card-state:
card-postal-code:
card-country:
signature:
tX3odBF2xPHqvhN4KVQZZBIXDveNi0eWA7717DNfcyqh2TpXqgCxlDjcKqdJXgsNLkY7
GkyuDyTF/m3SZif64giCLjJRKg0I6mqI1k/Dcm58D9hKCUttz4rFWRqhlFaj

#####################################################################
signature is of the following fields: id, date, transaction,
cyberkey, type, swversion, card-number, card-salt,
card-expiration-date, card-name, card-street, card-city,
card-state, card-postal-code, card-country

#####################################################################
Explanation:
salt is needed so that the hash stored at the server is less
informative. Server just remembers the "prefix" of the card
number and the hash of the combined card number and salt. If it
just hashed the card number, it would be recoverable with modest

effort by trying to hash all plausible numbers. We don't want
to store the card numbers on the server because it would make
the server files too valuable to bad guys.

4.2.2 BC4 - bind-credit-card-response

Description: Indicates that the process of binding a credit card
terminated. Returns success or failure.

#####################################################################
Sender: CyberServer
Receiver: CyberApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
id: mycybercashid
transaction: 12312314
date: 19950121100505.nnn
opaque:
EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb
nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV
4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs
rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo
QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==
$$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$

#####################################################################
Opaque Key: Session key from BC1 with same Transaction and ID

#####################################################################
Opaque Section Contents:

type: bind-credit-card-response
server-date: 19950121100506.nnn
swseverity: fatal/warning [absent if ok]
swmessage; message about obsoleteness of customer software
to be shown to the customer. [only present if SWSeverity present]
response-code: success/failure/etc.
card-number: 1234567887654321
card-type: visa
card-salt: 47562310
card-expiration-date: 01/99
card*: [other card* lines to also be given in CH.1 message]
message; Plain text for the user
can be multiple lines

#####################################################################
Signature is of the following fields: no-signature

#####################################################################
Explanation: All the card* lines can be saved as a blob to be
submitted in CH.1. card-expiration-date, card-number, card-salt,
and card-type should always be present.
Depending on reason for failure, not all fields may be present.

4.3 Customer Credit Card Purchasing Messages

In general, CyberCash involvement in the credit card purchasing cycle
starts after the user has determined what they are buying. When they
click on the CyberCash payment button, a PR1 message is sent by the
merchant to the customer as the body of a message of MIME type
application/cybercash.

If the customer wishes to proceed, they respond to the merchant with
a CH1. The merchant responds with a CH2 but between the receipt of
the CH1 and issuance of the CH2, the merchant usually communicates
with the CyberCash server via the CM* messages.

4.3.1 PR1 - payment-request

Description: This message is the first message that is defined
by CyberCash in the purchase-from-a-merchant process. The
shopping has completed. Now we are at the point of paying
for the purchases.

#####################################################################
Sender: MerchantApp
Receiver: CyberApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
type: payment-request
merchant-ccid: ACME-012
merchant-order-id: 1231-3424-234242
merchant-date: 19950121100505.nnn
note;
ACME Products

Purchase of 4 pairs "Rocket Shoes" at $39.95 ea.
Shipping and handling $5.00

Total Price: 164.80

Ship to:
Wily Coyote
1234 South St.
Somewhere, VA 12345
merchant-amount: usd 164.80
accepts: visa:CC001, master:CC001,amex:CC001,JCPenny:VK005,macy:VK006
url-pay-to: http://www.ACME.com/CybercashPayment
url-success: http://www.ACME.com/ordersuccess
url-fail: http://www.ACME.com/orderfail
merchant-signed-hash:
a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh
Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD
$$-CyberCash-End-lSLzs/vFQ0BXfU98LZNWhQ==-$$

#####################################################################
Opaque Key: no opaque section

#####################################################################
Opaque Section Contents: no opaque section

#####################################################################
merchant-signed-hash is the signature under the merchant's
private key of the hash of the following fields: type,
merchant-ccid, merchant-order-id, date, note, merchant-amount,
accepts, url-pay-to, url-success, url-fail

#####################################################################
Explanation:
This message is signed by the merchant but the customer cannot
directly verify this signature. When the payment is made, the
Customer includes the signature with the hash (derived by the
customer directly) in the payment. If these do not match, the
CyberCash will not perform the payment function.
accepts: The client software will only recognized single Word card
name in the accepts field of PR1. For example,
MasterCard
AmericanExpress
are recognized where as
Master card
American express
are not recognized. MasterCard and masterCard are both
recognized as master card.
Card type followed by key designator. For main line credit cards,
this will be a CC*. Client can use or ignore the * number as
it chooses. For proprietary card, this will be VK* where * is
the CheckFree key to use (1 based). Cards separated by comma,

key designator follows card type and colon.
url-pay-to is where the CH1 should be sent. url-fail and url-success
are where the browser should look after failure or success.

4.3.2 CH1 - credit-card-payment

Description: This message represents the presentation of a "credit
card for payment".

#####################################################################
Sender: CyberApp
Receiver: MerchantApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
type: card-payment
id: myCyberCashID
order-id: 1231-3424-234242
merchant-ccid: ACME-012
transaction: 78784567
date: 19950121100505.nnn
pr-hash: c77VU/1umPKH2kpMR2QVKg==
pr-signed-hash:
a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh
Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD
cyberkey: CC1001
opaque:
iff/tPf99+Tm5P7s3d61jOWK94nq9/+1jOWK9+vr9+b+94n3tYzmiveJ9/+09/334ubg
3rWM5Ir3ier3/7WM5Ir36+v35v73ife1jOWK94n3/7T3/ffm5uD+7N339/f39/eq3ff3
9/eFiJK5tLizsoeSmpW7uLS8/7iio7Wisfv38biio7uyufv3tfv35uH+7N3d9/exuKX3
5+z3vuu4oqO7srnsvvz8/venoqO0v7al/7iio7WisYy+iv7s3ff3p6KjtL+2pf/wi7nw
3ard3Q==
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Opaque Key: Created using CyberCash encrypting public key in
CyberKey.

#####################################################################
Opaque Section Contents:
swversion: 0.8win
amount: usd 10.00
card*: [from successful BC4 (includes card-expiration-date,
card-number, card-type, and card-salt)]
signature:
meO38aULnoP09VhTS2E56tnuZBRRlGfbwqaleZ9zNnv7YjExJKBFxuaqYTUDEj427HHh

mm9BVmHRwCq6+8ylZXixGHI1I9A/ufAMrpqMIi6DS3PRlc8WC3CCWoAHyAqr

#####################################################################
signature is under client private key of the following fields:
type, id, order-id, merchant-ccid, transaction, date,
pr-hash, pr-signed-hash, cyberkey, swversion, amount,
card*

#####################################################################
Explanation:
The pr-signed-hash field is the same as the merchant-signed-hash in
the PR1 message but has a different name for historic reasons.

4.3.3 CH2 - charge-card-response

Description: Return to customer from a CH1 attempt to pay via credit
card. Indicates success/failure.

#####################################################################
Sender: MerchantApp
Receiver: CyberApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
type: charge-card-response
merchant-ccid: ACME-012
id: myCyberCashID
transaction: 78784567
date: 1995121100500.nnn
merchant-date: 19950121100505.nnn
merchant-response-code: failure/success/etc.
pr-hash: 7Tm/djB05pLIw3JAyy5E7A==
pr-signed-hash:
a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh
Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD
merchant-message; This is a message to display to the user from the
merchant. Can be multiple lines... Is not secure.
opaque: [might not be present, see explanation]
EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb
nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV
4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs
rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo
QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################

Opaque Key: Same customer session key from CH1 passed through CM1
for ID and Transaction

#####################################################################
Opaque Section Contents (from CM.6):

server-date: 19950121100706.nnn
amount: usd 10.00
order-id: 1231-3424-234242
card*: [from successful BC4]
response-code: failure/success/etc.
swseverity: fatal/warning
swmessage; Tells CyberApp that it is obsolete. Display this
text to the user. [only present if SWSeverity present]
message;
Free text of the error/success condition.
This text is to be displayed to the customer
by the CyberCash application...

#####################################################################
Signature is of the following fields: no signature

#####################################################################
Explanation:
Opaque section optional because the CH1 to the merchant can fail due
to bad order-id, date, wrong merchant-ccid, etc., etc. So the
server may not be involved at all in which case there is no
mechanism for generating a secure opaque section. (It could even
be that merchant attempt to contact the server times out.)
If transaction makes it through server (via CM*) then
Response-Code at top level should mirror response-code to
merchant from server. (Hopefully the same as the
response-code to customer from server but the merchant can't
tell that.)
Note that there can be two messages, one from merchant and one
from the server.

4.4 Merchant Credit Card Purchasing Messages

The merchant presents credit card purchases, makes adjustments, and
the like via the CM* series. In general, the credit card cycle is
one of getting authorization for a purchase, then capturing the
purchase in a batch for clearance, then performing the clearance. It
is also possible to void a capture (i.e., remove an item from a
batch), and process credits (returns). (See section 5.1.)

Authorizations always come from an acquirer via the response to a CM1
or CM2 message. If capture is being performed by the acquirer or some
entity between the CyberCash server and the acquirer, this is done
via a CM3 or CM2 message depending on the arrangement between the
merchant and the entity doing the capture. Returns (credits) are
handled via message CM5. Message CM4 is provided for voiding a
capture or return before the batch is cleared. CM6 is the message
format used for responses to all the other CM* messages.

An MM* series has also been implemented for purely merchant
originated CyberCash charges as described in section 3.4.7

Current credit card dispute resolution systems assume that the
merchant knows the card number. Thus, to work with these systems,
special bypass messages have been set up that allow the merchant to
obtain, for a particular transaction, the information that CyberCash
otherwise goes to lengths to hide from the merchant. See sections
3.4.8 and 3.4.9. This makes the obtaining os such information by the
merchant an auditable event.

Many present day merchants operate in a "terminal capture" mode where
the authorizations are captured by the merchant and the merchant
later submits the settlement batch. Messages have been defined and
are being implemented so that such merchant captured batches can be
submitted via CyberCash.

4.4.1 CM1 - auth-only

Description: This message is used by the merchant to perform an
authorization operation on the credit card sent in by the
customer.

#####################################################################
Sender: MerchantApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
merchant-ccid: ACME-69
merchant-transaction: 123123
merchant-date: 19950121100705.nnn
merchant-cyberkey: CC1001
cyberkey: CC1001
opaque:
EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb
nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV

4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs
rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo
QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==
merchant-opaque:
6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf
aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGO
dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj
j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84
F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ
mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr
mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Merchant-Opaque Section Contents:

type: auth-only
order-id: 12313424234242
merchant-amount: usd 10.00
pr-hash: 7Tm/djB05pLIw3JAyy5E7A==
pr-signed-hash:
a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh
Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD
id: myCyberCashID
transaction: 78784567
date: 19950121100505.nnn
merchant-signature:
v4qZMe2d7mUXztVdC3ZPMmMgYHlBA7bhR96LSehKP15ylqR/1KwwbBAX8CEqns55UIYY
GGMwPMGoF+GDPM7GlC6fReQ5wyvV1PnETSVO9/LAyRz0zzRYuyVueOjWDlr5

#####################################################################
merchant-opaque key is generated from the CyberCash encrypting public
key identified in merchant-cyberkey.

Customer opaque section (Opaque) - see CH1.

#####################################################################
Opaque Section Contents & Signature: (exactly as in CH1)

swversion: 0.8win
amount: usd 10.00
card*: [from successful BC4 (includes card-expiration-date,
card-number, and card-salt)]
signature:
48SBKUfojyC9FDKCwdCYNvucgiDxYO9erZW4QndIXZRyheTHXH8OeIhwUkyLmgQSD/UK
+IX9035/jUkdNPOxUQq9y/beHS1HU9Fe0wlzfXYRtnjlqvQX+yUfQ4T7eNEs

#####################################################################

merchant-signature is on the following fields: merchant-ccid,
merchant-transaction, merchant-date, merchant-cyberkey, type,
order-id, merchant-amount, pr-hash, pr-signed-hash, id,
transaction, date, cyberkey

Customer Signature: see CH1

#####################################################################
Explanation:
The merchant signature ensures integrity of the majority of the
message. validation of the customer signature ensures that the
customer opaque part was not tampered or replaced.

4.4.2 CM2 - auth-capture

Description: Do authorization and actually enters charge for
clearance. Message just like CM1 except for different
type.

#####################################################################
Sender: MerchantApp
Receiver: CyberServer
#####################################################################
Sample Message:

[exactly the same as CM1 except

type: auth-capture

]

4.4.3 CM3 - post-auth-capture

Description: Captures a charge previously authorized. Message is
the same as CM1 except that it also has an authorization-code
field (which is also included in the signature) and the type
is different.

#####################################################################
Sender: MerchantApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
merchant-ccid: ACME-012

merchant-transaction: 123123
merchant-date: 19950121100705.nnn
merchant-cyberkey: CC1001
cyberkey: CC1001
opaque:
EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb
nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV
4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs
rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo
QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==
merchant-opaque:
6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf
aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGO
dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj
j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84
F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ
mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr
mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Merchant-Opaque Section Contents:

type: post-auth-capture
authorization-code: a12323
order-id: 1231-3424-234242
merchant-amount: usd 10.00
pr-hash: 7Tm/djB05pLIw3JAyy5E7A==
pr-signed-hash:
a/0meaMHRinNVd8nq/fKsYg5AfTZZUCX0S3gkjAhZTmcrkp6RZvppmDd/P7lboFLFDBh
Ec0oIyxWeHfArb3OtkgXxJ7qe0Gmm/87jG5ClGnpBnw0dY7qcJ6XoGB6WGnD
id: myCyberCashID
transaction: 78784567
date: 19950121100505.nnn
merchant-signature:
vxyEF1ZHn5Rgmtms3H3t/+UB6RAvZQA1AdddjvlS0H75N1x83FyJuh8V9Ok6t4EUQQZ6
Mnptzc6phJi3Ar0s0oumELsdc8upJdXpNpJV021PGJXfDKfHP0heJIWLodXr

#####################################################################
merchant-opaque key is generated from the CyberCash encrypting public
key identified in merchant-cyberkey.

Customer opaque section (Opaque) - see CH1.

#####################################################################
Opaque Section Contents & Signature: (exactly as in CH1)

swversion: 0.8win

amount: usd 10.00
card*: [from successful BC4 (includes card-salt, card-number,
and card-expiration)]
signature:
48SBKUfojyC9FDKCwdCYNvucgiDxYO9erZW4QndIXZRyheTHXH8OeIhwUkyLmgQSD/UK
+IX9035/jUkdNPOxUQq9y/beHS1HU9Fe0wlzfXYRtnjlqvQX+yUfQ4T7eNEs

#####################################################################
merchant-signature is on the following fields: merchant-ccid,
merchant-transaction, merchant-date, merchant-cyberkey, type,
authorization-code, order-id, merchant-amount, pr-hash,
pr-signed-hash, id, transaction, date, cyberkey

#####################################################################
Explanation:
The merchant signature ensures integrity of the majority of the
message validation of the customer signature ensures that the
customer opaque part was not tampered or replaced.

4.4.4 CM4 - void

Description: Voids out a charge/return if received before
clearance. Message is the same as CM1 except that it also has
a retrieval-reference-number field (which is also included in the
signature) and the type is different.

#####################################################################
Sender: MerchantApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
merchant-ccid: ACME-012
merchant-transaction: 123123
merchant-date: 19950121100705.nnn
merchant-cyberkey: CC1001
cyberkey: CC1001
opaque:
EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb
nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV
4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs
rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo
QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==
merchant-opaque:
6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf
aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGO

dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj
j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84
F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ
mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr
mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Merchant-Opaque Section Contents:

type: void
retrieval-reference-number: 432112344321
order-id: 1231-3424-234242
merchant-amount: usd 10.00
pr-hash: WATCQuH2q17lRuoxD78YBg==
pr-signed-hash:
8zqw0ipqtLtte0tBz5/5VPNJPPonfTwkfZPbtuk5lqMykKDvThhO0ycrfT7eXrn/hLUC
kXoSctahEVdw1KBJbp0EVr1zVzcN9Aa7m2fJgxNfiisTgIRW+PMaa78rn+Ov
id: myCyberCashID
transaction: 78784567
date: 19950121100505.nnn
Merchant-Signature: lkjladjslkjflsakjflkjsdljflsakjflkjsdljflsakjflkj
flsakjflkjsdljflsakjflkjsdljflsajflksdjflksdjflsdjssf=

#####################################################################
Merchant-Opaque key is generated from the CyberCash encrypting public
key identified in Merchant-CyberKey.

Customer opaque section (Opaque) - see CH1.

#####################################################################
Opaque Section Contents & Signature: (exactly as in CH1)

swversion: 0.8win
amount: usd 10.00
card*: [from successful bc4 (includes card-salt, card-number,
and card-expiration)]
signature:
48SBKUfojyC9FDKCwdCYNvucgiDxYO9erZW4QndIXZRyheTHXH8OeIhwUkyLmgQSD/UK
+IX9035/jUkdNPOxUQq9y/beHS1HU9Fe0wlzfXYRtnjlqvQX+yUfQ4T7eNEs

#####################################################################
merchant-signature is on the following fields: merchant-ccid,
merchant-transaction, merchant-date, merchant-cyberkey, type,
retrieval-reference-number, order-id, merchant-amount, pr-hash,
pr-signed-hash, id, transaction, date, cyberkey

#####################################################################

Explanation:
The merchant signature ensures integrity of the majority of the
message. Validation of the customer signature ensures that the
customer opaque part was not tampered or replaced.

4.4.5 CM5 - return

Description: Reverse a previous charge. Really sort of a negative
charge. Message just like CM1 except for different type.

#####################################################################
Sender: MerchantApp
Receiver: CyberServer
#####################################################################
Sample Message:

[exactly the same as CM1 except

type: return

]

4.4.6 CM6 - charge-action-response

Description: This receipt is given to the merchant as a receipt
for a completed charge action. Indicates success/failure/etc.

#####################################################################
Sender: CyberServer
Receiver: MerchantApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
merchant-ccid: ACME-012
merchant-transaction: 123123
merchant-date: 19950121100705.nnn
opaque:
EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb
nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV
4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs
rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo
QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==
merchant-opaque:
6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf
aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGO

dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj
j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84
F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ
mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr
mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Merchant-Opaque Key: Session key same as that of CM1/2/3/4/5 for
same Merchant-Transaction and Merchant-CCID.

Opaque Key: Same customer session key from CH1 passed through CM*
for ID and Transaction

#####################################################################
Merchant-Opaque Section Contents:

type: charge-action-response
server-date: 19950121100706.nnn
action-code: XXX [per ISO 8583]
response-code: failure/success/etc.
order-id: 1231-3424-234242
pr-hash: 7Tm/djB05pLIw3JAyy5E7A==
pr-signed-hash:
8zqw0ipqtLtte0tBz5/5VPNJPPonfTwkfZPbtuk5lqMykKDvThhO0ycrfT7eXrn/hLUC
kXoSctahEVdw1KBJbp0EVr1zVzcN9Aa7m2fJgxNfiisTgIRW+PMaa78rn+Ov
retrieval-reference-number: 432112344321
authorization-code: a12323
card-hash: 7Tm/djB05pLIw3JAyy5E7A==
{
card-prefix: nnxxxx [Returned if merchant is not full-PAN]
}
or
{
card-number: 1234567890123456 [Returned if merchant is full-PAN]
}
expiration-date: 12/34 [always present]
merchant-swseverity: fatal/warning
merchant-swmessage; Message for merchant about out of date
protocol number in $$ start line of merchant message.
merchant-message;
Free text of the error/success condition.
This text is for the merchant from the server...
id: myCyberCashID
transaction: 78784567
date: 19950121100505.nnn

Opaque (Customer) contents:

server-date: 19950121100706.nnn
amount: usd 10.00
order-id: 1231-3424-234242
card*: [from successful BC4]
response-code: failure/success/etc.
swseverity: fatal/warning
swmessage; Tells CyberApp that it is obsolete display this
text to the user. [only present if SWSeverity present]
message;
Free text of the error/success condition.
This text is to be displayed to the customer
by the CyberCash application...

#####################################################################
Signature is of the following fields: no signature

#####################################################################
Explanation:
retrieval-reference-number is needed for voids. authorization-code
is needed for post-auth-capture. These fields are each only
present in the CM6 if they were returned by the bank which
depends on what operation was being done.
card-prefix is first two and last four digits of card-number.
At merchant's bank's discretion the card-number or card-prefix is
returned.
card-hash is really the hash of the full card number and the salt
provided by the customer. card-hash is needed so the merchant
can, if they wish, sort customer transactions by card without
knowing the card number.
card* is the card* fields delivered in the CM* messages being
responded to. They appear in alphabetic order.
server-date duplicated in customer opaque area for security.
{}'s in column one just for clarity of alternatives and do not
actually appear in the message.
[]ed comments appear after some fields.

4.4.7 The MM* Message Series

The CM* message series above is the primary CyberCash credit card
purchase system for securely handling charges from CyberCash
customers. However, merchants, who are authorized by their acquiring
bank to accept such charges, may also receive telephone, mail, and
over-the-counter sales. To avoid any necessity for the merchant to
have a second parallel system to handle these charges, an MM1 through
MM6 message series is defined and has been implemented for these less
secure transactions.

The MM* messages look very similar to the CM* series but the
"customer opaque" section is actually signed by the merchant and no
separate customer CyberCash ID or prior card binding is required.
The MM* message examples are omitted here in the interests of
brevity.

4.4.8 CD1 - card-data-request

Description: Used by merchant to get card-number, etc., if
information needed by merchant to resolve a dispute.

#####################################################################
Sender: MerchantApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
merchant-ccid: ACME-69
merchant-transaction: 123123
merchant-date: 19950121100705.nnn
merchant-cyberkey: CC1001
cyberkey: CC1001
opaque:
EDD+b9wAfje5f7vscnNTJPkn1Wdi7uG3mHi8MrzLyFC0dj7e0JRjZ2PmjDHuR81kbhqb
nX/w4uvsoPgwM5UJEW0Rb9pbB39mUFBDLPVgsNwALySeQGso0KyOjMxNs1mSukHdOmDV
4uZR4HLRRfEhMdX4WmG/2+sbewTYaCMx4tn/+MNDZlJ89Letbz5kupr0ZekQlPix+pJs
rHzP5YqaMnk5iRBHvwKb5MaxKXGOOef5ms8M5W8lI2d0XPecH4xNBn8BMAJ6iSkZmszo
QfDeWgga48g2tqlA6ifZGp7daDR81lumtGMCvg==
merchant-opaque:
6BVEfSlgVCoGh1/0R+g1C143MaA6QLvKpEgde86WWGJWx45bMUZvaAu4LVeqWoYCqSGf
aWKUF7awol0h1i1jtgieyAcXB8ikvRJIsupSAwsRMyoNlekR6tucvfv/622JY7+n7nGO
dGbMzP0GJImh2DmdPaceAxyOB/xOftf6ko0nndnvB+/y2mFjdUGLtFQP/+3bTpZttZXj
j7RO1khe1UrAIk2TGQJmNw+ltsu0f42MgsxB8Q31vjPtoiPi5LEmD0Y4jlpJ7Jg2Ub84
F9vJhYpmzNkdiJUe83Hvo/xfJRbhafJpXFEsUZwQK0jU1ksU6CQd2+CPBB+6MxtsHoxJ
mjD6ickhd+SQZhbRCNerlTiQGhuL4wUAxzGh8aHk2oXjoMpVzWw2EImPu5QaPEc36xgr
mNz8vCovDiuy3tZ42IGArxBweasLPLCbm0Y=
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Merchant-Opaque Section Contents:

type: card-data-request
password: xyzzy
server-date: 19950121100505.nnn [optional]
order-id: 12313424234242
merchant-amount: usd 10.00
pr-hash: 7Tm/djB05pLIw3JAyy5E7A==

pr-signed-hash:
IV8gWHx1f8eCkWsCsMOE3M8mnTbQ7IBBcEmyGDAwjdbaLu5Qm/bh06OX1npe2d3Hijxy
+X8vKcVE6l6To27u7A7UmGm+po9lCUSLxgtyqyn3jWhHZpc5NZpwoTCf2pAK
id: myCyberCashID
transaction: 78784567
date: 19950121100505.nnn
merchant-signature:
8zqw0ipqtLtte0tBz5/5VPNJPPonfTwkfZPbtuk5lqMykKDvThhO0ycrfT7eXrn/hLUC
kXoSctahEVdw1KBJbp0EVr1zVzcN9Aa7m2fJgxNfiisTgIRW+PMaa78rn+Ov

#####################################################################
merchant-opaque key is generated from the CyberCash encrypting public
key identified in merchant-cyberkey.

Customer opaque section (Opaque) - see CH1.

#####################################################################
Opaque Section Contents & Signature: (exactly as in CH1)

swversion: 0.8win
amount: usd 10.00
card*: [from successful BC4 (includes card-expiration-date,
card-number, and card-salt)]
signature:
48SBKUfojyC9FDKCwdCYNvucgiDxYO9erZW4QndIXZRyheTHXH8OeIhwUkyLmgQSD/UK
+IX9035/jUkdNPOxUQq9y/beHS1HU9Fe0wlzfXYRtnjlqvQX+yUfQ4T7eNEs

#####################################################################
merchant-signature is on the following fields: merchant-ccid,
merchant-transaction, merchant-date, merchant-cyberkey, type,
password, server-date, order-id, merchant-amount, pr-hash,
pr-signed-hash, id, transaction, date, cyberkey

Customer Signature: see CH1

#####################################################################
Explanation:
[see also CM1 explanation]
The merchant may need to know the card involved and other
information in order to resolve a disputed transaction. This
information is all contained in the original CH1 embedded in the
CM1 for the transaction. If the merchant saves the CM1 and other
transaction information, they can send this CD1 message to the
server. While this reduces the pass through confidentiality of
the system, the merchant is then on record as aSKINg for this
particular credit card number and excessive CD1's from a merchant
can be flagged.
password is an extra level of security intended to be manually entered

at the merchant to authorize the unusual action. Server stores a
hash of the merchant-ccid and the password.

4.4.9 CD2 - card-data-response

Description: Respond to CD1 with failure or with success and card
data.

#####################################################################
Sender: CyberServer
Receiver: MerchantApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
merchant-ccid: ACME-012
merchant-transaction: 123123
merchant-date: 19950121100705.nnn
merchant-opaque: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$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Opaque Key: session key from CD1.

#####################################################################
Opaque Section Contents:

type: card-data-response
server-date: 19950121100706.nnn
response-code: failure/success/etc.
order-id: 1231-3424-234242
pr-hash: 7Tm/djB05pLIw3JAyy5E7A==
pr-signed-hash:
IV8gWHx1f8eCkWsCsMOE3M8mnTbQ7IBBcEmyGDAwjdbaLu5Qm/bh06OX1npe2d3Hijxy
+X8vKcVE6l6To27u7A7UmGm+po9lCUSLxgtyqyn3jWhHZpc5NZpwoTCf2pAK
card-hash: 7Tm/djB05pLIw3JAyy5E7A==
card-number: 4811123456781234
card-type: visa

card-name: John Q. Public
expiration-date: 01/99
merchant-swseverity: fatal/warning
merchant-swmessage; Message for merchant about out of date
protocol number in $$ start line of merchant message.
merchant-message;
Free text of the error/success condition.
This text is for the merchant from the server...
id: myCyberCashID
transaction: 78784567
date: 19950121100505.nnn

#####################################################################
Signature is of the following fields: no signature.

#####################################################################
Explanation:
This normally returns selected fields from the decoding of the
opaque part of a CH1 as sent to the server in a CD1.

4.5 Utility and Error Messges

A number of utility, status query, and special error reporting
messages have also been found necessary in implementing the CyberCash
system.

It is desirable to be able to test connectivity, roughly synchronize
clocks, and get an initial determination of what client protocol and
software versions are accepted. This is done via the P1 client to
server message and its P2 server to client response.

Clients need to be able to determine the status of earlier
transactions when the client or merchant has crashed during or has
suffered data loss since the transaction. Two transaction query
messages are defined, TQ1 and TQ2. One just queries and the other
also cancels the transaction, if it has not yet completed. The
response to both of these messages is a TQ3 response from the server.

Since the system operates in a query response mode, there are two
cases where special error messages are needed. If a query seems to
be of an undeterminable or unknown type, the UNK1 response error
message is sent. If a response seems to be of an undeterminable or
unknown type or other serious error conditions occur at the client or
merchant which should be logged at the CyberCash server, the DL1 or
DL2 diagnostic log message is submitted by the client or merchant in
question respectively.

4.5.1 P1 - ping

Description: Very light weight check that we have connectivity from
the customer to the server. Does no crypto to minimize
overhead.

#####################################################################
Sender: CyberApp
Receiver: CyberServer
#####################################################################
Sample Message:
$$-CyberCash-0.8-$$
type: ping
id: myCyberCashID [optional]
transaction: 123123213
date: 19950121100505.nnn
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Explanation:
id optional as persona may not have been set up yet.

4.5.2 P2 - ping-response

Description: Response to the P1 light weight ping. Does no
crypto to minimize overhead.

#####################################################################
Sender: CyberServer
Receiver: CyberApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
type: ping-response
id: myCyberCashID [if present in P1]
transaction: 12312313
date: 19950121100505.nnn
server-date: 19950121100506.nnn
swseverity: fatal/warning [absent if ok]
swmessage; Tells CyberApp that it is using an obsolete protocol.
Display this text to the user. [only present if SWSeverity
present]
response-code: success/failure/etc.
message;
Free text of the error/success condition.
This text is to be displayed to the sender

by their CyberCash application...
supported-versions: 08.win, 0.81win, 0.8mac
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Explanation:
swversion does not appear in P1 for security reasons so
swseverity and swmessage appear only if the server can tell
that things are old from the $$ header protocol version.
supported-versions lets client know as soon as possible what
versions are supported and, by implication, which are not. Does
not compromise security by having client say what version it
is.

4.5.3 TQ1 - transaction-query

Description: Client query to server for Transaction status.

#####################################################################
Sender: CyberApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
id: MyCyberCashID
date: 19950121100505.nnn
transaction: 12312314
cyberkey: CC1001
opaque:
VFaztHuj757Jrv+JxZFsHORy/zgkrxhBCu9cPdE04c1NnXzVlGOHygpSl+UGbUvnhkYl
21QQaHkaE3geccRk03cqFYoLNRCclImcsyeIZCgVt+2dJTj1V+E7R7ePQtCj+0gY42+V
L5BWhVtmDQFyg1DdJ6n3S/er6ZuObAjpcAogG+T1Na5dJmrTA1wRMiYVkqhXi2KMYdur
3U47P8ZGUza7W0MST3DgvviN0kVhtmHEnm515mo6NTQdfdxw9WZpy6vMqrBGk2nTgi2c
bnf+muO0+kiNPXVvEzRrO8o=
$$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$

#####################################################################
Opaque Key: generated from CyberCash encryption key identified in
CyberKey

#####################################################################
Opaque Section Contents:

type: transaction-query
swversion: 0.8win
begin-transaction: 1234

end-transaction: 4321
signature:
jJfFsKvOxLaV87gxu7lIPet3wIDwh1H2F61reYC9jmUrS6WAtUVFG9aCNuTEBoMixF0X
vD5oPfyheJRIlnL6i0c4o/bfyO3edKAacmWjTmKt6/4y9p3qgvKkSX8r9aym

#####################################################################
signature is of the following fields: id, date, transaction,
cyberkey, type, swversion, begin-transaction,
end-transaction

#####################################################################
Explanation:
This is a client status query of a previous transaction or
transactions.
begin-transaction and end-transaction can be the same.

4.5.4 TQ2 - transaction-cancel

Description: Client query to server for Transaction
cancellation/status.

#####################################################################
Sender: CyberApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
id: MyCyberCashID
date: 19950121100505.nnn
transaction: 12312314
cyberkey: CC1001
opaque:
VFaztHuj757Jrv+JxZFsHORy/zgkrxhBCu9cPdE04c1NnXzVlGOHygpSl+UGbUvnhkYl
21QQaHkaE3geccRk03cqFYoLNRCclImcsyeIZCgVt+2dJTj1V+E7R7ePQtCj+0gY42+V
L5BWhVtmDQFyg1DdJ6n3S/er6ZuObAjpcAogG+T1Na5dJmrTA1wRMiYVkqhXi2KMYdur
3U47P8ZGUza7W0MST3DgvviN0kVhtmHEnm515mo6NTQdfdxw9WZpy6vMqrBGk2nTgi2c
bnf+muO0+kiNPXVvEzRrO8o=
$$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$

#####################################################################
Opaque Key: generated from CyberCash encryption key identified in
CyberKey

#####################################################################
Opaque Section Contents:

type: transaction-cancel
swversion: 0.8win
begin-transaction: 1234
end-transaction: 4321
signature:
kD7DEav2uLQIYMtP9gbhYaBUpB2a5whNwnK2eXbbyTCf56F6dl3DIVf7D8Z4WxbY2YZn
ByRIKeqlhmss7fbdnBiDYmKfOuc+I4bi/Oslml5riaciQhTd2JdHG+PCcHwZ

#####################################################################
signature is of the following fields: id, date, transaction,
cyberkey, type, swversion, begin-transaction, end-transaction

#####################################################################
Explanation:
This is a client attempt to cancel a previous transaction or
transactions.
begin-transaction and end-transaction can be the same.

The transaction-cancel transaction (TQ.2) is defined between the
client and the server. This transaction permits the client to
query the status of an operation and to stop the operation from
occurring if it has not already occurred.

4.5.5 TQ3 - transaction-response

Description: Reports generated by a TQ1 or TQ2

#####################################################################
Sender: CyberServer
Receiver: CyberApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
id: mycybercashid
date: 19950121100505.nnn
transaction: 12312314
server-date: 19950121100505.nnn
opaque: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35XiC9Yn8flE4Va14UxMf2RCR1B/XoV6AEd64KwPeCYyOYvwbRcYpRMBXFLyYgWM+ME1
+yp7c66SrCBhW4Q8AJYQ+5j5uyO7uKyyq7OhrV0IMpRDPjiQXZMooLZOifJPmpvJ66hC
VZuWMuA6LR+TJzWUm4sUP9Zb6zMQShedUyOPrtw1vkJXU1vZ5aI8OJAgUcLEitcD+dsY
Df4CzA00fC10POkJ58HZB/pSBfUrHAa+IqMHyZkV/HBi9TjTwmktJi+8T9orXS0jSvor
dMTGWn0ifETy2VXt
$$-CyberCash-End-0QXqLlNxrn4GNQPPk9AO1Q==-$$

#####################################################################
Opaque Key: Session key from TQ1/TQ2 with same Transaction and ID.

#####################################################################
Opaque Section Contents:

type: transaction-response
response-code: success/failure/etc.
message; general free form text message from server to
customer....
swseverity: fatal/warning
swmessage; Message indicating that CyberApp software is obsolete.
May be multiple lines.
report-fee: usd 0.15 [if non-zero]

transaction-1: old-transaction-number
transaction-status-1: success/failure/pending/cancelled/etc.
server-date-1: 19951212125959.nnn
date-1: 19950121100505.nnn
type-1: auth-only/etc.

#####################################################################
Signature is of the following fields: no signature

#####################################################################
Explanation:
Report-fee is the notification that this report cost a fee and is
only present if there is a fee.
There can be multiple transaction for the same transaction number as
there could have been a auth, post-auth-capture, void, etc.

Terms
"original transaction" refers to the payment or other transaction
that is being queried or canceled.
Note: this transaction may not actually reside at the server.
"request" refers to the requesting TQ.2 or TQ.1 message

id: id from the request message
date: date from the request message
transaction: transaction from the request message

server-date: current date/time
type: transaction-response
response-code: response code for request message, can be one of:
"success" means the request message was processed. Does not imply
query or cancellation status of the request.
"failure-hard" means that the request message was not processed
due to being ill-formed or otherwise inoperable.
"failure-swversion" means that the request message was not
processed due to software revision problems.
message: the message applies only to the TQ transaction, not to the
status of the transactions being queried or canceled. The
message is provided according to the response-code as: "success"
- message is omitted. "failure-hard" - use standard hard failure
message. "failure-swversion" - use standard swversion message for
fatal
swseverity: applies to request message
swmessage: applies to request message
-- per query/cancel fields ('N' is a series from 1 to N) --
transaction-N: transaction number of original transaction, or if
the original transaction is not present in server the transaction
number that the query / cancel request refers to
transaction-status-N: status of original transaction, may be one of:
"success" the original transaction was successfully processed.
If request was TQ.2, cancellation is not performed.
"failure" the original transaction was not successfully processed.
If request was TQ.2, cancellation is not performed (however,
there is nothing to cancel, so it's all the same to the customer
app).
"pending" the original transaction is still being processed and
final disposition is not known.
"canceled" the original transaction has been canceled by the server.
Later arrival of the original transaction will not be processed,
but will be returned with a "failure-canceled" returned.
server-date-1: server-date field from original transaction or
omitted if original transaction is not present in the server"
date-1: date field from original transaction or omitted if original
transaction is not present in the server"
type-1: type field from original transaction or omitted if original
transaction is not present in the server"

4.5.6 UNK1 - unknown-error

Description: This is the response sent when the request is so
bad off you can't determine what type it is or the type is
unknown to you. Sent from Merchant to Client or from Server
to Merchant or from Server to Client.

#####################################################################
Sender: MerchantApp or CyberServer
Receiver: CyberApp or MerchantApp
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
type: unknown-error
unknown-error-message:
Text message of error condition to display to user. (CyberCash
wrapper not found, wrapper integrity check fails, unknown protocol
version specified, unknown type specified, etc.)
{
server-date: 19950121100506.nnn [if sent by server]
}
or
{
merchant-date: 19950121100506.nnn [if sent by merchant]
}
x-id: mycybercashID
x-transaction: 123123213
x-date: 19950121100505.nnn
x-cyberkey: CC1001
x-opaque:
2DqiOQfGRZjzddWpEZwGsJnoTsp9Yiri8DE9cPUMPsJ7lTFuE4XHi4QfN2cAipDB2G/G
9hr7Hj4u4xfMky7nPvJurClZejkI8eNp8iXLtrfS4DhR4yCFQjCiKk0dh83p+DDsFVV7
TI3Du2B15sQS+SdaoPwkfVDnJv4Y+b7vu2cN7bG7exCkBapBcJZbReNaWX5sf+U8ypfw
5V6QdMOzNXpef3z+cTTWfGOtmn9T1Pwo1Yi9ObyIf/wiK+IPb+bBZ9UwLZSB+qVMfJmX
GnHXO3AnA/PD+jKYCtsm2Gxv2WB3CuezOyzPtORuqLp5ubgnLBF9aBBjxwLdbn+cp5sm
lw51IHbmo1Jj7H6wyNnRpEjy4tM73jcosBfGeQDHxgyH1uaiFNr2D+WvmuYo7eun2dsy
Wve2O/FwicWHvkg5aDPsgOjzetsn1JCNZzbW
$$-CyberCash-End-7Tm/djB05pLIw3JAyy5E7A==-$$

#####################################################################
Opaque Key: see explanation

#####################################################################
Opaque Section Contents: see explanation

#####################################################################
Signature is of the following fields: see explanation

#####################################################################
Explanation:
This message is sent as a response when you can't find or understand
even the type of a message to you. It will always have type and
unknown-error-message fields at the beginning. Any fields from
the request that are parseable are simply echoed back in the UNK1

message with "x-" prefixed to it. Thus, if an x-opaque appears,
it was whatever the opaque was in the original request, etc. If
you can decrypt the opaque section, you don't want to put the
results here in the clear!
{}'s in the first column are to group alternatives only and do not
appear in the message.
Since the customer originates exchanges with merchant and server
and merchant originates exchanges with server, this message
will only be emitted from the merchant to the customer or the
server to the customer or merchant. It should generally just
be logged for debugging purposes.
You may need to watch out for denial of service via forged or
replayed UNK1 messages.

4.5.7 DL1 - diagnostic-log

Description: Client diagnostic log of bad message from either
merchant or server.

#####################################################################
Sender: CyberApp
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
id: MyCyberCashID
date: 19950121100505.nnn
transaction: 1234
cyberkey: CC1001
opaque:
2DqiOQfGRZjzddWpEZwGsJnoTsp9Yiri8DE9cPUMPsJ7lTFuE4XHi4QfN2cAipDB2G/G
9hr7Hj4u4xfMky7nPvJurClZejkI8eNp8iXLtrfS4DhR4yCFQjCiKk0dh83p+DDsFVV7
TI3Du2B15sQS+SdaoPwkfVDnJv4Y+b7vu2cN7bG7exCkBapBcJZbReNaWX5sf+U8ypfw
5V6QdMOzNXpef3z+cTTWfGOtmn9T1Pwo1Yi9ObyIf/wiK+IPb+bBZ9UwLZSB+qVMfJmX
GnHXO3AnA/PD+jKYCtsm2Gxv2WB3CuezOyzPtORuqLp5ubgnLBF9aBBjxwLdbn+cp5sm
lw51IHbmo1Jj7H6wyNnRpEjy4tM73jcosBfGeQDHxgyH1uaiFNr2D+WvmuYo7eun2dsy
Wve2O/FwicWHvkg5aDPsgOjzetsn1JCNZzbW
$$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$

#####################################################################
Opaque Key: generated from CyberCash encryption key identified in
CyberKey

#####################################################################
Opaque Section Contents:

type: diagnostic-log
message: incorrect order-id
swversion: 0.8win

x-type: original-message-type
x-transaction: original-transaction-number
x-opaque: [if can't decrypt]
9/eFiJK5tLizsoeSmpW7uLS8/7iio7Wisfv38biio7uyufv3tfv35uH+7N3d9/exuKX3
5+z3vuu4oqO7srnsvvz8/venoqO0v7al/7iio7WisYy+iv7s3ff3p6KjtL+2pf/wi7nw

#####################################################################
Explanation:
Client application does not expect a response for this message. The
decrypted original message will be in the opaque section unless
decryption fails. If decryption fails then un-decrypted opaque
in the original will be sent.
This message will be sent to a different script or socket or host
than normal messages so that it will just be absorbed and never
generate an UNK1 response or anything, even if this message
itself is screwed up.

4.5.8 DL2 - merchant-diagnostic-log

Description: Merchant diagnostic log of bad message from server.

#####################################################################
Sender: CyberMerchant
Receiver: CyberServer
#####################################################################
Sample Message:

$$-CyberCash-0.8-$$
merchant-ccid: MyCyberCashID
merchant-transaction: 1234
merchant-date: 19950121100505.nnn
merchant-cyberkey: CC1001
merchant-opaque:
2DqiOQfGRZjzddWpEZwGsJnoTsp9Yiri8DE9cPUMPsJ7lTFuE4XHi4QfN2cAipDB2G/G
9hr7Hj4u4xfMky7nPvJurClZejkI8eNp8iXLtrfS4DhR4yCFQjCiKk0dh83p+DDsFVV7
TI3Du2B15sQS+SdaoPwkfVDnJv4Y+b7vu2cN7bG7exCkBapBcJZbReNaWX5sf+U8ypfw
5V6QdMOzNXpef3z+cTTWfGOtmn9T1Pwo1Yi9ObyIf/wiK+IPb+bBZ9UwLZSB+qVMfJmX
GnHXO3AnA/PD+jKYCtsm2Gxv2WB3CuezOyzPtORuqLp5ubgnLBF9aBBjxwLdbn+cp5sm
lw51IHbmo1Jj7H6wyNnRpEjy4tM73jcosBfGeQDHxgyH1uaiFNr2D+WvmuYo7eun2dsy
Wve2O/FwicWHvkg5aDPsgOjzetsn1JCNZzbW
$$-CyberCash-End-kchfiZ5WAUlpk1/v1ogwuQ==-$$

#####################################################################

Opaque Key: generated from CyberCash encryption key identified in
CyberKey

#####################################################################
Opaque Section Contents:

type: merchant-diagnostic-log
server-date: 19950121100505.nnn [optional]
message: incorrect order-id

x-type: original-message-type
x-transaction: original-transaction-number
x-opaque: [if can't decrypt]
9/eFiJK5tLizsoeSmpW7uLS8/7iio7Wisfv38biio7uyufv3tfv35uH+7N3d9/exuKX3
5+z3vuu4oqO7srnsvvz8/venoqO0v7al/7iio7WisYy+iv7s3ff3p6KjtL+2pf/wi7nw

#####################################################################
Explanation:
Merchant application does not expect a response for this message. The
decrypted original message will be in the opaque section unless
decryption fails. If decryption fails then un-decrypted message
will be sent.
This message will be sent to a different script or socket or host
than normal messages so that it will just be absorbed and never
generate an UNK1 response or anything even if this message
itself is screwed up.

4.6 Table of Messages Described

The following 31 messages are described in this document.

C = Customer App, M = Merchant App, S = CyberCash Server

FLOW SECTION NAME

C->S 4.2.1 BC.1 bind-credit-card
S->C 4.2.2 BC.4 bind-credit-card-response

C->M 4.3.2 CH.1 credit-card-payment
M->C 4.3.3 CH.2 credit-card-response

M->S 4.4.8 CD.1 card-data-request
S->M 4.4.9 CD.2 card-data-response

M->S 4.4.1 CM.1 auth-only
M->S 4.4.2 CM.2 auth-capture
M->S 4.4.3 CM.3 post-auth-capture

M->S 4.4.4 CM.4 void
M->S 4.4.5 CM.5 return
S->M 4.4.6 CM.6 charge-action-response

C->S 4.5.7 DL.1 diagnostic-log
M->S 4.5.7 DL.2 merchant-diagnostic-log

C->S 4.1.3 GA.1 get-application
S->C 4.1.4 GA.2 get-application-response

M->S 4.4.7 MM.1 merchant-auth-only
M->S 4.4.7 MM.2 merchant-auth-capture
M->S 4.4.7 MM.3 merchant-post-auth-capture
M->S 4.4.7 MM.4 merchant-void
M->S 4.4.7 MM.5 merchant-return
S->M 4.4.7 MM.6 merchant-charge-action-response

C->S 4.5.1 P.1 ping
S->C 4.5.2 P.2 ping-response

M->C 4.3.1 PR.1 payment-request

C->S 4.1.1 R.1 registration
S->C 4.1.2 R.2 registration-response
C->S 4.5.3 TQ.1 transaction-query
C->S 4.5.4 TQ.2 transaction-cancel
S->C 4.5.5 TQ.3 transaction-response

S->C, S->M, M->C
4.5.6 UNK.1 unknown-error

5. Future Development

CyberCash is extending the facilities available through the CyberCash
system. We are committed to implementing a full cash system,
including efficient transfer of small amounts of money, the extension
of the credit card system to handle terminal capture and clearances,
and other improvements.

5.1 The Credit Card Authorization/Clearance Process

There are six steps in credit card processing as listed below. The
first four are always involved if a transacation is completed. The
fifth and sixth are optional.

(1) authorization: merchant contacts their acquiring back which
normally contacts the card issung bank and returns to the
merchant an approval/guarantee or a disapproval. This

temporarily decreases the available credit on the card.
(2) capture: the charge information for a purchase is entered by
the merchant into a batch.
(3) clearance: a batch of items is processed. This actually causes
the items in the batch to appear on credit card statements as
sent by the issuing bank to its carholders.
(4) settlement: the actual interbank transfer of net funds.
(5) void: the merchant undoes step 2 (or 6) and causes a charge (or
credit) to be removed from a batch. Must be done before the
batch is processed.
(6) credit: the merchant causes a "negative charge" or credit to be
entered into a batch. This will appear on the cardholders
statement.

The fourth step, settlement, is entirely within the banking community
and does not concern us here. CyberCash 0.8 provides messages to do
1, 1&2, 2, 5, and 6. This is adequate for credit card processor
systems where the batch is accumulated at the bank or between the
bank and the merchant. CyberCash 0.8 supports such "host capture"
systems. Other credit card processor systems require the merchant to
accumulate the batch. Such systems are frequently referred to as
"terminal capture". This makes actions 2, 5, and 6 internal to the
merchant but requires messages to perform action 3. Such batch
clearance messages will be included in future versions of the
CyberCash merchant and server software.

5.2 Lessons Learned

The continuing rapid development of the CyberCash system is an
interesting experience. The system must deal with many existing
browsers and legacy banking systems. Existing credit card processors
that convey transactions to acquiring banks have complex and varied
interfaces. The sophistication of security attacks on the Internet
is growing rapidly.

In the face of such a rapidly changing environment, it was essential
to adopt a general message framework so that messages and fields
could be added as they were found necessary. Any attempt to reduce
the system to a small number of perfectly opimized messages in
advance would have doomed the system to failure. (As of mid-October
1995, the total number of CyberCash messages defined, including those
planned for cash and microcash, enhancements to the credit card
system, and some old messages being phased out in favor of improved
replacements, is just over a hundred.)

Flexible operational and error handing facilities are also, as usual,
the bulk of the system. Version numbering and tracking has proved to
be quite important and merchant versioning is being added.

Use of text for messages has proven very beneficial. This makes it
possible to easily deal with messages using common everyday tools
such as text editors and spead sheets. Use of binary TLV (type,
length, value) encoding or the like is certainly possible but imposes
a significantly higher level of complexity on every tool that has to
deal with the messages.

Encryption and decryption impose some difficulties in development.
Any confusion about decryption keys or algorithms will render
encrypted material meaningless and tools are needed to provide
decyrption for debugging outside of normal program operation. But
this pales compared with the stringencies imposed by signatures. All
parts of the system must have absolutely identical ideas as to the
exact bit patterns to be hashed or signed and their exact order.
Seemingly trivial differences in capitalization, punctuation,
framing, order, or the like, in addition to any disagreement about
keys or algorithms, will lead to frustrating failures of signatures
to match. Passing signatures through an intermediate system and
checking them at a third system, as is done when a customer's
signature is passed through a merchant and checked at the CyberCash
server, compounds the problem.

6. Security Considerations

The CyberCash Version 0.8 Credit Card system provides substantial
protection to payment messages as described above in sections 1.2,
2.2.4, and 2.2.5. However, it provides no privacy to the shopping
interaction which is essentially outside of its purview. It also
provides no protection against dishonest merchants other than those
normally available with credit card purchases. Care must be taken to
avoid loss of control of the machines on which parts of this system
runs or security may be compromised.

Current credit card dispute resolution systems require deliberate
bypasses be implemented for some of the security normally established
by CyberCash as described in section 3.4.

References

[ISO 4217] - Codes for the representation of currencies and funds

[ISO 8583] - Financial transaction card originated messages -
Interchange message specifications, 1993-12-15.

[RFC822] - Crocker, D., "Standard for the format of ARPA Internet
text messages", STD 11, RFC822, UDEL, August 1982.

[RFC1521] - Borenstein, N., and N. Freed, "MIME (Multipurpose
Internet Mail Extensions) Part One: Mechanisms for Specifying and
Describing the Format of Internet Message Bodies", RFC1521,
Bellcore, Innosoft, September 1993.

[RFC1766] - Alvestrand, H., "Tags for the Identification of
Languages", UNINETT, March 1995.

Authors' Addresses

Donald E. Eastlake 3rd
CyberCash, Inc.
318 Acton Street
Carlisle, MA 01741 USA

Phone: +1 508 287 4877
EMail: dee@cybercash.com

Brian Boesch
CyberCash, Inc.
2100 Reston Parkway, Suite 430
Reston, VA 22091 USA

Phone: +1 703-620-4200
EMail: boesch@cybercash.com

Steve Crocker
CyberCash, Inc.
2100 Reston Parkway, Suite 430
Reston, VA 22091 USA

Phone: +1 703-620-4200
EMail: crocker@cybercash.com

Magdalena Yesil
CyberCash, Inc.
555 Twin Dolphin Drive, Suite 570
Redwood City, CA 94065 USA

Phone: +1 415-594-0800