1. IADIS e-Society 2004
Lisbon
Portugal
Building multi-services
in personal mobile devices
based on partially trusted domains
Miguel Pardal (mflpar@yahoo.co.uk)
Alberto Cunha (alberto.cunha@inesc.pt)
July 19th 2004

2. Overview
• Personal devices
• Self-contained services
– Examples
• Multi-services
– Opportunities
• Work in progress
– Pilot implementation
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3. Personal devices
• Examples:
– Smart card
– Mobile phone
– PDA
• Enable information access anywhere
– With little effort
– At reasonable cost
• Can make service delivery more effective
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4. Service delivery model
• Device-based service
– The user has a device that can be used in a terminal
– Data networks support information flows with business
servers
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5. Service examples
• Transport tickets
• Automated banking
• Mobile communication
• Health card
• Public identification
• Etc.
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6. Service components
Service Supervising
User Device Terminal Infrastructure
organization
Magnetic stripe ATM Secure private Bank(s)
Automated card network
banking Bank servers
Mobile
SIM Card Mobile Cellular Network Network
communication phone Back-end servers operator
Smart-card Point-of- Transport network Transport
sale authority
Transportation Entry
point
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7. Service examples
• Transport tickets
• Automated banking
• Mobile communication
• Health card
• Public identification
• Etc.
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8. Selected subset of services
• Main requirements:
– Valuable
– Large scale and widespread
– Fast interactions
• To satisfy these requirements
economically:
– Distributed architecture
– Almost-never-connected to
remote servers
• Security must be enforced on local interactions
– Consistency checked later
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9. Self-contained service
• The service typically:
– Belongs to a single business area
– Has specific devices, terminals and infrastructure
– Has a supervising organization to ensure trust
• Strengths
– Standard design and technology
• Weaknesses
– ‘One device per service’
– Difficult to extend beyond their original use
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10. New value approach
• Improve services
– Customers
• Same device for multiple services
• More convenience and other potential benefits
– Ex. discounts
– Service providers
• Reach customers through new channels
– Supervising organizations
• Increase infrastructure return-on-investment
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11. Multi-services
• Compose different self-contained services
– Ex. device level or terminal level
• Aiming for more open and dynamic services
– Assume only partial trust
– Support restricted information and functionality sharing
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12. Our goal
• Develop models and tools to produce
technical assurances that allow
organizations to establish the partial trust
relationship between them to deliver the
service
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13. Related work
• Multi-application interoperability
– Standard application frameworks for cards or
other devices
• Security assurance mechanisms
• Auditing
• Device certification
– Hardware
– Software
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14. Pilot implementation
• Identify benefits and limitations of approach
• Use of payment network to load new tickets in
secure transport card
– Transport operator does not give up control of its
security keys for ticket loading to the payment service
provider
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15. Pilot approach
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16. Why partial trust?
• There are already examples of combined services:
– Co-branded credit cards
• However, they’re managed by a single dominant
organization, fully trusted by all business partners
– In this sense, they’re not much different from self-
contained services!
• True multi-services entail only partial trust
– Existing approaches assume a total trust domain
– We want to make trust explicit in models and tools
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17. Questions & Answers
“Going from an issuer card to a user
card…”
In (Zóreda and Otón, 1994)
“(The device is) their electronic Identity,
their reliable key to e-services”.
In OSCIE vol. 3-5, eEurope Smart Cards, 2003
Thank you!
Miguel Pardal
mflpar@yahoo.co.uk
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