Consideration of a Mobile Payment System using Endorsement in MANETs for a Disaster Area

Ojetunde Babatunde

Nara Institute of Science and Technology

Division of Foundations of Software

Introduction (1/2)

One of the major problems in disaster areas

People have no cash at hand to buy necessary amenities

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Introduction (2/2) Due to non-availability of network infrastructure People have no access to

Their bank account Electronic transaction

An infrastructureless Payment System is required3

Many researches are conducted on Mobile Payment Systems

Related Work on Payment System

Online service1

Computation overhead1

Privacy of users1

Compensate users2

Work without third party vendor2

[1] Hu, Z., Liu, Y., Hu, X., and Li, J.: Anonymous Micropayments Authentication (AMA) in Mobile Data Network, IEEE INFOCOM 2004, Twenty-third Annual Joint Conference of the IEEE Computer and Communications Societies Issue: 7 March (2004)

[2] Chitra Kiran, N., and Kumar, G. N.: Implication of Secure Micropayment System Using Process Oriented Structural Design by Hash chain in Mobile Network, IJCSI International Journal of Computer Science, Issues, Vol. 9, Issue 1, No 2, January (2012)

No mobile payment system developed for disaster areas 4

Main Contributions to Mobile Payment System

•Dynamic topology

•Disconnected network

•It takes two days to communicate with the bank

MANETs Issues

•Authentication issues

•Impersonation

•Double spending

•Resetting phone

Fraudulent Transactions

•Money is deducted online real-time through direct access to bank

No need for merchants to

trust users

Mobile payment system for disaster areas Need no connection to the

bank to work

Avoid fraud Users account balance is

checked by surrounding mobile nodes

Guarantee payment of each transaction by endorsing

Challenges Contributions

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Customer

Merchant

Bank/MP Service provider

Customer

Merchant

Send transaction order

Forward payment information

Deduct money from the customer’s

account

Supply the item to the customer

Merchant and customer agree to start transaction

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Normal Transaction Without Disaster (1/2)

Normal Transaction Without Disaster (2/2) This method is not suitable in a disaster area due

to the challenges mentioned above

We propose an endorsement based mobile payment system for disaster areas

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Introduction Endorsement Based Mobile Payment System Schemes to Prevent Attacks Conclusion

Outline

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All users are required to register with a Bank in advance

The Bank issues digital certificates to all users at registration

Merchant Customer Endorser Bank

We assume that all users except the bank are in the disaster area

Endorsement Based Mobile Payment System (1/8)

Registration process

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Endorsement Based Mobile Payment System (2/8)

Merchant Customer A

Send transaction order “ I want to buy an apple from you”

Merchant

Verify the customer using pre-digitally signed picture

Customer A

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How to check the Identity of a Customer A user sends digitally signed picture to merchant

Merchant checks and compares digitally signed picture with customer’s appearance

Merchant confirms the digital signature of the bank

Another kind of biometric authentication can also be used for verification

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Merchant Bank/MP Service provider

Forwards the forms to the Bank“Apple cost $2”

It takes at least two days for a message to get to Bank

No means of confirming customer’s account balance Network infrastructure is not available Customer collects his/her money before the bank deducts

money for items purchase

Bank will not have money to deduct from customer Merchant will lose money

Endorsement Based Mobile Payment System (3/8)Motivation for Endorsement

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To prevent this and allow transaction in a disaster area We introduce endorsement

Merchant Endorsers

Create and forward Billing Form“Customer A wants to buy $2 apple. Do

you guarantee the transaction?”

Endorsement Based Mobile Payment System (4/8)

Merchant forwards the billing form to endorsers To obtain guarantee that the transaction can be paid by

endorsers in case customer fails to pay

We assume that endorsers are available during transaction

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A person agrees to pay for another person, who fails to pay for an item.

The agreement is made before a disaster happens

Endorsement

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Many Challenges of Endorsement Based Payment System 1

Endorsers

What Happen?

If endorsers are not available Frequent change in topology of

networks Transaction cannot be successfully

completed without an endorser

A customer can have more than one endorser

If one endorser is not available another endorser can endorse Reduce endorser’s liability

Endorsers are rewarded for successful transaction15

MerchantEndorsers

Authenticate the Merchant and Create endorsement form

“I guaranteed customer A purchase of $2 apple”

Endorsement Based Mobile Payment System (5/8)

Endorsers send endorsement form back to the merchant

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Merchant Bank/MP Service provider

Forward the forms to the Bank

“Customer A bought an apple at $2”

It takes at least two days for a message to get to Bank

Endorsement Based Mobile Payment System (6/8)

Send transaction confirmation to customer and endorsers

Deliver items to customer

Merchant Customer A

Endorsers 17

Merchant

Bank/MP Service provider

Bank pays merchant“Pay merchant $2”

Customer A

Bank/MP Service provider

Deduct responding money from customer’s account“Deduct $2 from customer A’s account”

The bank authenticates all users and checks for consistency of messages

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Endorsement Based Mobile Payment System (7/8)

Bank/MP Service provider Endorsers

Deduct money from endorsers“Deduct $2 from endorsers”

Send acknowledgement to Merchant, Customer and Endorser

Customer A

Merchant

Endorser may have no money or collude with a customer Mechanism to check endorser balance

We assume that some endorsers will pay

However, if there is no money in customer’s account

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Endorsement Based Mobile Payment System (8/8)

Introduction Endorsement Based Mobile Payment System Schemes to Prevent Attacks Conclusion

Outline

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Customer and endorsers may carry out Reset and Recovery attacks

A reset and recovery is when a user, Backups all data Resets phone to default state Recovers all data already used

Reset attack cannot be detected if there is no network connection

We assume that, Most but not all users are trustable Most of the users do not change location often

Many Challenges of Endorsement Based Payment System 2

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Reset and Recovery Attack

Customer and endorsers can collude to do fraud Customer A has no money Endorsers have no money

There is no means of confirming endorsers account balance

Endorsers will endorse many transactions without paying

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Many Challenges of Endorsement Based Payment System 3Collusion Attack

Monitoring Based on Location Information

• Proof user are in a particular location…

One-time Session Token• Prevent user from using same message

E-coin• Confirm amount in user account

Blind Signature

• Ensure anonymity of message

Schemes to Prevent Attacks

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Preventing Collusion and Checking Balance

Bank creates unique tokens called e-coin

Users account balance is divided into e-coins of same amount of money

Customer ¥10,000 eT1, eT2, eT3, ….. eT10

E-coin is limited to endorsers

The e-coin contains Customer ID E-coin identifier GPS coordinates HELLO message interval Monitoring customer signature

Only bank can encode the ID and identifier

Endorser attaches e-coin to endorsement

Bank deletes e-coin from endorser account if a customer defaults

If a customer does not default, the bank reissues e-coin with new identifier

Endorsement without e-coin is rejected

E-coin

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Preventing Reset Attack (1/2)

User

User

Custome

r

User

User User User

User

Each user constantly exchanges HELLO message to show their respective location

HELLO

HELLO

HELLOHELLO

HELLO:Customer ID

GPS Coordinates

HELLO

HELLO HELLO:

If a user stays in a location for a long time Other users monitor their

transactions

If a user fails to broadcast HELLO messages Not in range Lost of connection

If a user phone is lost or turned off Cannot provide collected

HELLO messages Find endorsers Provide endorser’s confirmation

GPS coordinates in HELLO message constantly replace the e-coin GPS coordinates

Intervals between HELLO messages are added to e-coin

Monitoring Based on Location

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Allows a person to get a message signed by another party without revealing the message

Original Message Envelope containing Message and Carbon paper

Signature

Envelope is signed (by signer)

Message has now been signed

Signature

Sent to Signer

Envelope Removed

Binding Process

There is an existing research on how to get digital blind signature

Blind Signature Scheme

Preventing Reset Attack (2/2)

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The techniques stated above are adopted to prevent attacks Reset and Recovery attacks Collusion attack

A Customer or endorsers Blinds the message Broadcasts the message to other users

Monitoring customer Checks GPS coordinates and HELLO message intervals Checks e-coin attached to the endorsement message Creates one-time session token and appends to message Signs message with his/her digital signature

Preventing Attacks

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Conclusion Proposed a new mobile payment system by

Adopting infrastructureless mobile ad-hoc networks (MANETs)

Allowing users to purchase amenities in disaster areas Providing secure transactions

Users authenticates each other without a network connection a third party

Users anonymity is protect by using user’s nickname Ensures confidentiality of messages and transaction Ensures integrity Reliability of transaction messages

The proposed system suits the limitation of mobile payment transaction in a disaster area

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