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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

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Goals

Desirable wallet properties / features

Define wallet interaction model

Define Clean APIs for wallet and its components

Build Prototype

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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

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An Example

Session Initiation Dilbert -> Amazon.com

Instrument Class Negotiation Dilbert: MasterCard,

PonyCash, CyberCoin Amazon.Com: MasterCard,

VISA, CyberCoin ==> MasterCard, CyberCoin

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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

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An Example

Instrument Instance Selection: Dilbert’s Citibank MasterCard

Transaction Execution SET (2KP) PAY

Close Session

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SWAPEROO Architecture

User Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

WalletController

UserInterface

ClientAPI

UserInterfaceAPI

Instrument Instances

Protocols

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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

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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

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Wallet Interaction Model

Open SessionInstrument Class

NegotiationProtocol NegotiationProtocol SelectionInstrument SelectionTransaction ExecutionClose Session

Open Session

Instrument ClassNegotiation

ProtocolNegotiation

ProtocolSelection

InstrumentSelection

CloseSession

TransactionExecution

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Wallet Interaction Model

Open SessionInstrument Class Instrument Class

NegotiationNegotiationProtocol NegotiationProtocol SelectionInstrument SelectionTransaction ExecutionClose Session

Open Session

Instrument ClassNegotiation

ProtocolNegotiation

ProtocolSelection

InstrumentSelection

CloseSession

TransactionExecution

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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

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Wallet Interaction Model

Open SessionInstrument Class NegotiationProtocol NegotiationProtocol SelectionInstrument SelectionTransaction ExecutionTransaction ExecutionClose Session

Open Session

Instrument ClassNegotiation

ProtocolNegotiation

ProtocolSelection

InstrumentSelection

CloseSession

TransactionExecution

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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

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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

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Transaction Execution

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Trade-offs / Issues

Where to put what functionality?

User Profile Manager

Instrument Manager

Protocol Manager

Communication Manager

WalletController

UserInterface

ClientAPI

UserInterfaceAPI

Instrument Instances

Protocols

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Trade-offs / Issues

User Interaction number of steps vs.

likelihood of an error

Open Session

Instrument ClassNegotiation

ProtocolNegotiation

ProtocolSelection

InstrumentSelection

CloseSession

TransactionExecution

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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

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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

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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/)