1. Securing Electronic Portfolios
Patrick Lougheed, Robin Johnson, Mayo Jordanov, Brittney Bogyo, Vive Kumar, and Jane Fee
29 October 2004

2. What kinds of security? End-to-end security
Confidentiality of interactions
Confidentiality of assessment
Security of published portfolios
Security of portfolio transfers
Verification of artifact authenticity

3. End-to-end security Client <-> Server Server <-> Database
HTTP over SSL
Server <-> Database
Database connection over SSL (or SSH tunneled)
Problem is now security at endpoints
Client (unable to control)
Server (able to control)

4. Database Security Largest vulnerability Therefore biggest target
Possibly tens of thousands of users
Stores assessment data
Successful attacker can:
Harvest of data
Change marks
Change interactions
Administrators shouldn’t have access to confidential data
Therefore biggest target

5. Confidentiality of Interactions
In assessment systems, teacher/learner interactions should be considered private
Private only between teacher and learner
Possibly made public upon approval of both parties

6. Confidentiality of Assessment
Minimally two way, more likely three way; learner, teacher, person with responsibility for marks
An overseer, such as a principal or teacher-in-charge
Always private, never made public
Marks need to be signed as well as encrypted
Make sure they’re legitimate

7. Security of Published Portfolios
One person may have multiple published portfolios
Presenting different material to different intended audiences for different purposes
For example: one published version for a job application at Sun Microsystems; another for an application at Microsoft; a third for assessment purposes
Need to make sure only certain audiences can access certain portions

8. Security of Portfolio Transfers
System-to-system direct transfers
Easily secured
Indirect transfers
And archive of some sort is kept in someone’s possession for an indefinite period of time
How do we know the portfolio hasn’t been tampered with?
When do we care?

9. Verification of Artifact Authenticity
Hardest problem of this set to solve
Can we determine if an artifact:
Was in fact created by the portfolio creator? (or some portion of it, or they’re authorized for it….)
Is an official document?
Has been tampered with?
Example: university transcript; off-line methods of verification may not work in the online world

10. How do we solve these problems?
End-to-end security
SSL wrapping
Database security
Proper user authentication
Database level encryption (not as easy as it sounds)
SSL
Security of published portfolios
Username/password authentication

11. The SPARC System Focus so far on database security
Use of both public key encryption and symmetric encryption
Keyed on user’s password, so they don’t need to remember anything new, and are less likely to forget
Data is encrypted to multiple people simultaneously
Everything encrypted with a master key, so recovery from a lost password is trivial

12. The SPARC System

13. What problems are we left with? Part 1
Multiple recipient encryption
Portfolios are the inverse of most traditional encryption systems
Not one-to-one or many-to-one
Rather one-to-many
RSA multiple-recipient public-key encryption
Has been published academically - still potentially problems with it
Left with encrypting a single message multiple times with multiple keys; does this pose a risk?

14. What problems are we left with? Part 2
Every user needs a key
To encrypt data for a user, that user needs a key; teachers also need a signing key to sign marks
Leads to the possibility of gaining knowledge about later keys if we know something about earlier keys, assuming the system generates all the keys

15. What problems are we left with? Part 3
Client verification
For portfolio transfers…
How do we find the people to transfer to?
How do we know that the people we’re transferring to are correctly identifying themselves?
For viewing portfolios…
How do we know people are who they say they are or belong to the organization they say they do?
Public Key Infrastructure!
Downsides: expensive, many companies don’t have a PKI infrastructure, most employees have no access to company’s keys

16. What problems are we left with? Part 4
Verification of authenticity
How do we trace an artifact's history?
Can we verify it came from a particular source?
Need to be able to:
Verify a signed artifact
Verify an artifact's origin
Verify the artifact hasn’t been tampered with
Single biggest problem: just because it’s signed, doesn’t mean it’s signed by the right people!

17. People Involved Patrick Lougheed Brittney Bogyo Robin Johnson
Brittney Bogyo
Robin Johnson
Mayo Jordanov
Henry Ng
Vive Kumar