1 swaperoo neil daswani, dan boneh, hector garcia-molina, steven ketchpel, andreas paepcke stanford...

1

SWAPEROO

Neil Daswani, Dan Boneh, Hector Garcia-Molina, Steven Ketchpel, Andreas Paepcke Stanford University

A Simple Wallet Architecture for Payments, Exchanges, Refunds, and Other Operations

2

Goals

Desirable wallet properties / features

Define wallet interaction model

Define Clean APIs for wallet and its components

Build Prototype

3

Wallet Features

Extensible: support multiple existing and newly developed instruments and protocols

Non-Web-Centric: can be implemented in non-web environments; extensibility across devices

Symmetric: common services across commerce applications; extensibility across commerce applications

Client-Driven: user initiates all operations, including wallet invocation

4

An Example

Session Initiation Dilbert -> Amazon.com

Instrument Class Negotiation Dilbert: MasterCard,

PonyCash, CyberCoin Amazon.Com: MasterCard,

VISA, CyberCoin ==> MasterCard, CyberCoin

5

An Example

Protocol Negotiation for MasterCard Dilbert: SET (2KP) Amazon.Com: SET (2KP), SET (3KP),

or Unencrypted ==> SET (2KP)

Protocol Selection: SET (2KP)Available Operations: PAY, CREDIT

6

An Example

Instrument Instance Selection: Dilbert’s Citibank MasterCard

Transaction Execution SET (2KP) PAY

Close Session

7

SWAPEROO Architecture

User Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

WalletController

UserInterface

ClientAPI

UserInterfaceAPI

Instrument Instances

Protocols

8

Function Descriptions

Instrument Manager: encryption of instruments

Protocol Manager: protocol invocation

Communication Manager: low-level, synchronous messaging

User Profile Manager: stores access control information

Wallet Controller: coordinates wallet operations & enforces access control

9

Symmetric Vendors/Banks

Customer Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

VendorController

UI

Instrument Manager

Protocol Manager

Communication Manager

BankController

UI

Vendor Wallet Bank Wallet

Account Profile Manager

10

Wallet Interaction Model

Open SessionInstrument Class

NegotiationProtocol NegotiationProtocol SelectionInstrument SelectionTransaction ExecutionClose Session

Open Session

Instrument ClassNegotiation

ProtocolNegotiation

ProtocolSelection

InstrumentSelection

CloseSession

TransactionExecution

11

Wallet Interaction Model

Open SessionInstrument Class Instrument Class

NegotiationNegotiationProtocol NegotiationProtocol SelectionInstrument SelectionTransaction ExecutionClose Session

Open Session

Instrument ClassNegotiation

ProtocolNegotiation

ProtocolSelection

InstrumentSelection

CloseSession

TransactionExecution

12

Instrument Class Negotiation

User Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

WalletController

UI Customer Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

VendorController

UI

User Wallet Vendor Wallet

13

Wallet Interaction Model

Open SessionInstrument Class NegotiationProtocol NegotiationProtocol SelectionInstrument SelectionTransaction ExecutionTransaction ExecutionClose Session

Open Session

Instrument ClassNegotiation

ProtocolNegotiation

ProtocolSelection

InstrumentSelection

CloseSession

TransactionExecution

14

Transaction Execution

User Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

WalletController

UI Customer Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

VendorController

UI

User Wallet Vendor Wallet

15

Transaction Execution

subscribe(EXECUTE_TRANSACTION)

VendorApplication

SETProtocol

checkPrivileges (inv, Citibank Mastercard, PAY)

OK

WalletController

Vendor Wallet

executeTransaction(inv,Citibank Mastercard,PAY)

UserApplication

WalletController

User ProfileManager

SETProtocol

doOperation(PAY,Citibank Mastercard,PAY)

EXECUTE TRANSACTION SETProtocol2KP PAY

doOperation(PAY,Citibank Mastercard,PAY)

OK

notify (EXECUTE_TRANSACTION)

End-User Wallet

16

Transaction Execution

17

Trade-offs / Issues

Where to put what functionality?

User Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

WalletController

UserInterface

ClientAPI

UserInterfaceAPI

Instrument Instances

Protocols

18

Trade-offs / Issues

User Interaction number of steps vs.

likelihood of an error

Open Session

Instrument ClassNegotiation

ProtocolNegotiation

ProtocolSelection

InstrumentSelection

CloseSession

TransactionExecution

19

Trade-offs / Issues

Security vs. Customization i.e., User Interface & UI API

User Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

WalletController

UserInterface

ClientAPI

UserInterfaceAPI

Instrument Instances

Protocols

20

Implementation &Future Work

Implementation C++ (PalmOS) Java (Windows) PonyCash

Future Work Populate the wallet Experiment with other devices/environments

(i.e. smart cards, mobile phones, web, etc.) Abstract Data Manager

21

Summary / Contributions

Desirable wallet properties: extensibile, symmetric, non-web-centric, client-driven

Defined wallet interaction model

Clean APIs for wallet and its components

Prototype Implementation in Java & C++(available at http://www-db.stanford.edu/~daswani/wallets/)