Secure Electronic Transaction

Creating Debts Online with Confidence

SET Objectives

To encrypt critical information over the internet

To separate the merchant from credit card information

To link payment and order information

SET

Alice as the Cardholder

Bob’s Beer Delivery as the Merchant

Visa as the Issuer

Wachovia as the Acquirer/Payment Gateway

Starring

Dual Signature

How Bob can prove Alice paid for Natural Light and not Samuel Adams

Dual Signature Creation

PI

OI

||

H PIMD

H OIMD

POMDH

DSE kra

How Bob Uses the DS

DS PIMD OI

DS = Ekra[ H( H(PI) || H(OI) ) ]

Ekua [ Ekra[ H( H(PI) || H(OI) ) ] ]

H( H(PI) || H(OI) )

H( PIMD || H(OI) )

=!

=

How Wachovia Uses the DS

DS PI OIMD

DS = Ekra[ H( H(PI) || H(OI) ) ]

Ekua [ Ekra[ H( H(PI) || H(OI) ) ] ]

H( H(PI) || H(OI) )

!

H( H(PI) || OIMD )

Payment Processing

Purchase RequestAlice to Bob’s Beer Delivery

Payment AuthorizationBob’s Beer Delivery to WachoviaWachovia to Visa

From Alice To Bob’s Beer

Dig Envelope

PIMD

Order Info

Dual Sig

+

+

+

+

+

Alice’sCert.

Used by Bob’s Beer Delivery(Order Related)

Sent on by Bob’s Beer Delivery to Wachovia (Money Related)

Contains Key To Decrypt Dual Sig(KPUB-Alice )

Payment Processing

Purchase RequestAlice to Bob’s Beer Delivery

Payment AuthorizationBob’s Beer Delivery to Wachovia Wachovia to Visa

From Alice To Bob’s Beer

Dig Envelope

PIMD

Order Info

Dual Sig

+

+

+

+

+

Alice’sCert.

Used by Bob’s Beer Delivery(Order Related)

Sent on by Bob’s Beer Delivery to Wachovia (Money Related)

Contains Key To Decrypt Dual Sig(KPUB-Alice )

From Alice Through Bob To Wachovia

Dig Envelope

+

Money Info Encrypted UsingSymmetric Key

Symmetric Key Encrypted UsingWachovia’s Public Key

Bob’s Beer To Wachovia

PaymentInfo

Dual Sig

OIMD

E

Temporary Symmetric Key Generated by Alice

KS

Digital Envelope

EKSDig Envelope

KPUB-Wachovia

Obtaining The Payment Info

D

PaymentInfo

Dual Sig

OIMD

Dig Envelope KSD

KPRI-Wachovia

KS

SET Interoperability

Software development on SET protocol– Brokat, Entrust, Globeset, GTE, IBM,

TrinTech, Verisign

SET costs– Software development– Hardware and runtime increases with high

volume of transactions

Conclusion

Non-repudiation

Inherited credit card risks

Not widely used