Digi cash
- 1. Digital Cash Dr Paras Kothari
- 2. Overview ►Monetary Freedom ►Digital Cash and its importance ►Achieving Digital Cash ►Disadvantages with digital cash ►Conclusion
- 3. Why Monetary Freedom? ► Monetary transactions Cash, Cheque, and Credit Card transactions ► Organizations keep records for purchases, communication, financial history ► Can be against privacy ► Consumers need to trust that net will make safeguard their privacy and transactions, while continuing to make shopping easy and enjoyable ► Freedom from Unit of transaction
- 4. Digital Cash ►Digitally signed payment message ►Piece of information which is recognized as having value ►This piece is then accepted by Merchants ►True digital cash stores and conveys meaning in and of itself Not just represent value in bank account ►This is used in today’s e-commerce
- 5. Key Elements of Digital cash ► Minimum requirements Confidentiality ►Anonymity ►No monitoring Authentication ►Digital Cash is valid ►Banks can authenticate parties Integrity ►Should not be easy to alter a piece of digital cash Non-Repudiation Confirmation that the transaction was complete Settlement
- 6. Key Elements of Digital cash (contd.) ►Other characteristics Divisibility Off-line capability Peer-to-Peer transactions Scalability
- 7. Achieving digital cash ►Register Based Systems A counter is stored on a smart card ►E-cash Tokens storable on card/computer ►Digital Cheques Similar to paper Cheques+ digital signatures ►Electronic coupons Similar to digital Cheques but limited to one issuer
- 8. Protocols for Digital Cash ► Withdrawal phase of secure credit card scheme ► Ram sends her public key k to bank ► Bank returns a signature for it
- 9. Protocols (contd.) ► Payment phase ► n-acct number ► Her public key k signed by bank ► Shop can verify Ram’s acct, pub key ► Shop can verify sign. on the receipt, amount ► Receipt forwarded to bank
- 10. Blind Signatures ►A bank can create a digital bank note by signing a message which specifies the serial number and value of the note ►Bank sends to Ram ►Ram sends it to Krishna ►Krishna deposits with bank account
- 11. Blind Signatures (contd.) ►Problem: Bank knows that Ram and Krishna have just mad a transaction. ►Solution: Blinding signatures Multiply the note number by a random factor before sending it to bank Divide the number after its signed by bank ►Double spending problem ►Verification with bank when a digital note is used
- 12. Issues with Digital Cash ►Easy to do illegal transactions if forged/ technology failures ► Large amount transaction paper will be heavy!! ► Consumer resistance: Lack of complete trust ►Other issues: Power failures Loss of records Undependable software
- 13. Conclusion ►Promising Technology ►Monetary freedom ►Several issues to resolve before we can truly achieve this
- 14. Query Session More learning is required to solve doubts …