Table of Contents
Electronic payment, microcommerce, and digital cash systems
Outline
Money
Electronic money
The pattern of electronic commerce
Electronic commerce requirements
More requirements
SSL-based payment systems
Yeah, but…
A problem with credit cards
SET
SET, nyet?
Electronic cash
Microcommerce
Microcommerce (continued)
Previous alternatives
What’s the problem?
Why is microcommerce difficult?
Designing a financial system
Financial system options
Cryptography
Public-key cryptography 1: RSA
Public-key cryptography 2: El Gamal
Public-key crypto 3: more tricks
Shared-key cryptography
One-way hash functions
Applications of one-way hashing
Performance of cryptography
Performance of disks and networks
Vendor performance calculations
Financial agent calculations
Increase transaction size
Make commissions bigger
Remove some on-line computation
Meet the MilliCent Customer
Vendor Characterization
MilliCent Vendors: Big or Small?
Why Microcommerce
Internet Business Models
The Microcommerce Model
Atomicity
Anonymity and privacy
Mondex, VisaCash
CyberCoin
PayWord (Rivest and Shamir)
PayWord (cont.)
MicroMint (Rivest and Shamir)
MiniPay (now IBM Micro Payment)
DigiCash
MilliCent : concepts
The big picture
A typical purchase
A scrip purchase (by a customer)
The broker as a vendor
Initial scrip purchase in MilliCent
A closer look at a piece of scrip
A closer look at the scrip stamp
Scrip stamp generation
Scrip stamp validation (at vendor)
Making a purchase
Request stamp computation
The customer secret
Customer secret computation (at broker or vendor)
The cost of processing a purchase
Advantages of scrip
Features for vendor
Features for customer
Non-features
Where did a transaction take place?
When did a transaction take place?
Fraud
Bad transactions
Issues we haven’t begun to discuss
Further issues
Initial implementation strategy
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