Overview about the Digital Cash

1. DIGITAL CASH OVERVIEW
Prepared by
Osama Mabrouk Khaled
PhD, Computer Science

2. WHAT IS DIGITAL CASH?
 How does it work?
There are a number of electronic cash protocols. To a
degree, all digital cash schemes operate in the following
manner. A user installs a "cyber wallet" onto computer.
Money can be put in the wallet by deciding how much is
needed and then sending an encrypted message to the
bank asking for this amount to be deducted from the user's
account. The bank reads the message with private key
decryption and verifies if it has been digitally signed in order
to identify the user. The bank then generates "serial
numbers", encrypts the message, signs it with its digital
signature and returns it. The user is now entitled to use the
message (coin or token) to spend it at merchant sites.
Merchants receive e-cash during a transaction and see that
it has been authorized by a bank. They then contact the
bank to make sure the coins have not been spent
somewhere else, and the amount is credited to the
merchant's account. [2],[3]
Essentially, digital cash mimics the functionality of paper cash. More
technically, digital cash is a payment message bearing a digital signature
which functions as a medium of exchange or store of value. [3]
[3]

3. OFFLINE DIGITAL CASH SOLUTION PROPERTIES
 Prone to Security
 Anonymity
 Portability
 Two-way Payments
 Offline Capability
 Divisibility
 Infinite Duration
 Wide Acceptability
 User Friendliness
 Unit of Value or Monetary freedom
References: [1], [2]

4. DISADVANTAGE OF DIGITAL CASH
 The unconditional anonymity that some of these systems
provide is much greater that what paper cash provides its
users today.
 There is also a pressing issue in regards to the technology
involved in digital cash. Power failures, loss of records, and
undependable software often cause a major setback in
promoting the technology.
 Double-Spending possibilities are high
References: [2], [3]

5. WHAT IS USER-CENTRIC DESIGN?
 is a design philosophy and a process in which the needs, wants, and
limitations of end users of a product are given extensive attention at each
stage of the design process.
 The major difference from other product design philosophies is that user-
centered design tries to optimize the product around how users can,
want, or need to use the product, rather than forcing the users to change
their behavior to accommodate the product.
 A user-centered design is focused around the rhetorical situation. The
rhetorical situation shapes the design of an information medium. There
are three elements to consider in a rhetorical situation: Audience,
Purpose, and Context.
 Audience: The audience is the people who will be using the solution. The designer
must consider their age, geographical location, ethnicity, gender, education, etc.
 Purpose: The purpose is what the solution is targeting to or what problem is the
solution trying to address.
 Context: The context is the circumstances surrounding the situation. The context
often answers the question: What situation has prompted the need for this solution?
Context also includes any social or cultural issues that may surround the situation.
Reference: [4]

6. WHY USING USER-CENTRIC WITH E-CASH MOBILE NFC?
 Benefits of User-Centric Design:
 Digital Cash are more efficient, effective, and safe.
 Assists in managing users’ expectations and levels of
satisfaction with the digital cash.
 Users develop a sense of ownership for the digital cash.
 Products require less redesign and integrate into the
environment more quickly.
 The collaborative process generated more creative
design solutions to problems.
References: [5]

7. WHAT IS MOBILE NFC?
 Near field communication (NFC) is a set of standards for smartphones
and similar devices to establish radio communication with each other by
touching them together or bringing them into close proximity, usually no
more than a few centimeters. Present and anticipated applications
include contactless transactions, data exchange, and simplified setup of
more complex communications such as Wi-Fi. Communication is also
possible between an NFC device and an unpowered NFC chip, called a
"tag".
 Usages of NFC:-
 Matching encrypted security code and transporting access key;
 Due to short transmission range, NFC-based transactions are possibly secure;
 Instant payments and coupon delivery using your handset, as we do with your credit
card or debit card;
 Exchange of information such as schedules, maps, business card and coupon
delivery in a few hundred milliseconds;
 Pay for items just by waving your phone over the NFC capable devices
 Transferring images, posters for displaying and printing
References: [6]

8. HOW CAN MOBILE NFC PROMPT E-CASH?
 Secured by nature due to short range.
 User Friendly in the communication process.
 If using NFC-enabled SIM, then digital cash will be
more secured and moveable.
 Digital cash on NFC mobile is similar to a normal
ticket that has a value.
 Double spending can be eliminated using peer-to-
peer e-cash money transfer.
 Anonymous with the presence of the money holder.
 NFC consumes less power, and is fast with small
data size packets.

9. REFERENCES
1. Isabelle Simplot-Ryl, Issa Traor´e, and Patricia Everaere. Distributed Architectures for
Electronic Cash Schemes: A Survey. The International Journal of Parallel, Emergent
and Distributed Systems. August 29, 2008.
2. Damodar Nagapuram. Digital Cash Survey.
http://www.cs.washington.edu/education/courses/csep590/06wi/finalprojects/nagapura
m.doc.
3. Amit, Hiren, Kevin, Kai. Digital Cash Survey.
http://www.cs.bham.ac.uk/~mdr/teaching/modules03/security/students/SS4/DigitalCash
.doc (2004)
4. User-Centered Design. http://en.wikipedia.org/wiki/User-centered_design.
5. Chadia Abras, Diane Maloney-Krichmar, Jenny Preece. User-Centered Design.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.94.381&rep=rep1&type=pdf
6. Near field communication. http://en.wikipedia.org/wiki/Near_field_communication