On Cashlike Digital Payment Systems Daniel A. Nagy, Department of - - PowerPoint PPT Presentation

▶
on cash like digital payment systems
SMART_READER_LITE
LIVE PREVIEW

On Cashlike Digital Payment Systems Daniel A. Nagy, Department of - - PowerPoint PPT Presentation

Feb 15, 2023 448 likes •646 views

ICETE 2005 On Cashlike Digital Payment Systems Daniel A. Nagy, Department of Mathematics and Statistics, Queens University, Kingston, Ontario, Canada Overview of Cash Peertopeer anyone can pay and receive payment no

slide-1
SLIDE 1

On Cash−like Digital Payment Systems

Queen’s University, Kingston, Ontario, Canada Daniel A. Nagy, Department of Mathematics and Statistics,

ICETE 2005

slide-2
SLIDE 2

Overview of Cash

Peer−to−peer

− anyone can pay and receive payment − no distinction between buyers and sellers

Transactions are anonymous and irreversible

− strangers can deal with each other − no need for identification, no risk of identity theft

No special equipment for receiving or paying

− a wallet comes handy, but it’s not required

Minimal transaction costs − ideally zero

− the buyer pays as much as the seller receives

slide-3
SLIDE 3

Digital Cash Challenge

Double Spending

− digital information is easy to reproduce − duplicates must not be accepted as payment

Privacy & Transparency

− noone should be able to find out

* how much cash a given person holds * in what transactions a given person participates

− anyone should be able to find out

* how much cash has been issued by a given issuer * if an issuer fails to honor its obligations

slide-4
SLIDE 4

Environment (assumptions)

Low−bandwidth, instantenous communication (messaging) is cheap and ubiquitous Asymmetric cryptography is not prohibitively expensive but not necessarily available at all times to all parties (especially to payers) Public records are cheap to access and search by content

slide-5
SLIDE 5

Dramatis Personæ

Ivan

the payment system’s operator, acting on behalf

  • f the issuer

− has a permanent network address and digital identity − is on−line at all times − is able to perform all sorts of cryptographic calculations in large quantities

Alice

payer

Bob

receiver of payment

slide-6
SLIDE 6

Ivan

Maintains public records of value Receives and verifies requests Updates public records of value

Serial Number: 0000000004 Value: 20 units Challenge: Emission request for 20 Signature:

Ivan

slide-7
SLIDE 7

Issued for:

Ivan

Maintains public records of value Receives and verifies requests Updates public records of value

Serial Number: 0000000004 Value: 20 units Challenge: Emission request for 20 Signature:

Ivan

Exchange request:

slide-8
SLIDE 8

Serial Number: 0000000005 Value: 20 units Challenge: Issued for: Signature:

Ivan

Ivan

Maintains public records of value Receives and verifies requests Updates public records of value

Exchange request:

slide-9
SLIDE 9 Serial Number: 0000000004 Value: 20 units Challenge: Issued for: Emission request for 20 Signature:

Ivan

Payment Scenario

Ivan Alice Bob

slide-10
SLIDE 10 Serial Number: 0000000004 Value: 20 units Challenge: Issued for: Emission request for 20 Signature:

Ivan

Micro−payment

Ivan Alice Bob

slide-11
SLIDE 11 Serial Number: 0000000004 Value: 20 units Challenge: Issued for: Emission request for 20 Signature:

Ivan

Micro−payment

Ivan Alice Bob Exchange request:

slide-12
SLIDE 12 Serial Number: 0000000005 Value: 20 units Challenge: Issued for: Signature:

Ivan

Micro−payment

Ivan Alice Bob

Exchange request:
slide-13
SLIDE 13 Serial Number: 0000000004 Value: 20 units Challenge: Issued for: Emission request for 20 Signature:

Ivan

Ivan Alice Bob

Payment with Receipt

slide-14
SLIDE 14 Serial Number: 0000000004 Value: 20 units Challenge: Issued for: Emission request for 20 Signature:

Ivan

Bob

Pay 20

Bob

Pay 20 Ivan Alice Bob

Payment with Receipt

slide-15
SLIDE 15 Serial Number: 0000000004 Value: 20 units Challenge: Issued for: Emission request for 20 Signature:

Ivan

Bob

Pay 20 Exchange request: Ivan Alice Bob

Payment with Receipt

slide-16
SLIDE 16 Serial Number: 0000000005 Value: 20 units Challenge: Issued for: Signature:

Ivan

Bob

Pay 20 Ivan Alice Bob

Payment with Receipt

Exchange request:
slide-17
SLIDE 17

depends on the nature of the cryptographic challenges scales with transaction value, as determined by the users can be adequate for users with low computational resources addresses insider fraud

Security

slide-18
SLIDE 18

Conclusions

The proposed payment system matches paper cash more closely than existing digital solutions Adequate for the whole range of transaction values ranging from micro−payments to high− value transfers Provides for transparent issuer govenrance Open−source implementation: http://sf.net/projects/epoint