Portfolios need verifiability

Having verified information included in learner-owned portfolios looks attractive to employers and others, but perhaps it would be better to think in terms of verifiable information, and processes that can arrange verification on demand.

Along with Scott Wilson and others, I was at a meeting recently with a JISC-funded project about doing electronic certificates, somewhat differently from the way that Digitary do them. Now, the best approach to certifying portfolio information is far from obvious. But Higher Education is interested in providing information to various people about activities and results of those who have attended their institution, and employers and others are keen to know what can be officially certified. When people start by imagining an electronic transcript in terms their understanding of a paper transcript, inevitably the question of how to make it “secure” will come up, echoing questions of how to prevent forgery of paper certificates.

Lately, I have been giving people my opinion that portfolio information and institutionally (“primary source”) verified information are different, and don’t need to interact too closely. Portfolio holders may write what they like, just as they do in CVs, and if certificates or verification are needed, perhaps the unverified portfolio information can provide a link to a verified electronic certificate of achievement information (like the HEAR, the UK Higher Education Achievement Report, under development). This meeting moved my understanding forward from this fairly simple view, but there are still substantial gaps, so I’ll try to set out what I do understand, and ask readers for kind suggestions about what I don’t.

As Scott could tell you much more ably than me, there are plenty of problems with providing digitally signed certificates for graduates to keep in their own storage. I won’t go into those, just to say that the problem is a little like banknotes: you can introduce a new clever technology that is harder to forge, but sooner or later the crooks will catch up with you, and you have to move on to ever more complex and sophisticated techniques. So, in what perhaps I may call “our” view, it seems normally preferable to keep original verified information at source, or at some trusted service provider delegated by the primary source. There are then several ways in which this information can be shown to the people who wish to rely on its verified authority. In principle, these are set out in Scott’s page on possible architectures for the HEAR. But in detail, again at the meeting I realised something I hadn’t figured out before.

We have already proposed in outline a way in which each component part of an achievement document could have its own URI, so that links could be made to particular parts, and differential permissions given to each part. (See e.g. the CEN EuroLMAI PDF.) If each part of an achievement document is separately referenceable, the person to whom the document refers (let’s call this person the holder again) could allow different people to view different parts, for different times, etc., providing that achievement information servers can store that permission information alongside the structured achievement information itself.

Another interesting technical approach, possible at least in PebblePad (Shane Sutherland was helpfully contributing to the meeting), is transparently to include information from other servers, to view and manage in your portfolio tool. The portfolio holder would directly see what he or she was making available for others to view. The portfolio system itself might have general permission to access any information on the achievement information server, with the onward permissions managed by the portfolio system. Two potential issues might arise.

  1. What does giving general permission to an e-portfolio system mean for security? Would this be too much like leaving an open door into the achievement information server?
  2. As the information is presented by the portfolio server, how would the viewer know that the information really comes from the issuer’s server, and is thus validated? A simple mark may not be convincing.

A potential solution to the second point might start with the generation of a permission token on the issuer’s server whenever a new view is put together on the portfolio system. Then the viewer could request a certificate that combined just the information that was presented in that view. But, surely, there must be other more general solutions?

The approach outlined above might be satisfactory just for one achievement information server, but if the verified information covering a portfolio is distributed across several such servers, the process might be rather cumbersome, confusing even, as several part certificates would have to be shown. Better to deal with such certificates only as part of a one-off verification process, perhaps as part of induction to a new opportunity. Instead, if the holder were able to point from a piece of information to the one or more parts of the primary records that backed it up, and then to set permissions within the portfolio system for the viewer to be able to follow that link, the viewer could be given the permission to see the verified information behind any particular piece of information. Stepping back a little, it might look like this. Each piece of information in a portfolio presentation or system is part of a web of evidence. Some of that evidence is provided by other items in the portfolio, but some refers to primary trustable sources. The method of verification can be provided, at the discretion of the portfolio holder, for permitted viewers to follow, for each piece of information.

One last sidestep: the nice thing about electronic information is that it is very easy to duplicate exactly. If there is a piece of information on a trusted server, belonging to a portfolio holder, it is in principle easy for the holder to reproduce that piece of information in the holder’s own personal portfolio system. Given this one-to-one correspondence, for that piece of information there is exactly one primary source of verification, which is the achievement information server’s version of just that piece of information. The information in the portfolio can be marked as “verifiable”, and associated with its means of verification. A big advantage of this is that one can query a trusted server in the least revealing way possible: simply to say, does this person have this information associated with them? The answer would be, “yes”, or “no”, or “not telling” (if the viewer is not permitted to see that information).

Stepping back again, we no longer need any emphasis on representing “verified” information within a portfolio itself, but instead the emphasis is on representing “verifiable” information. The task of looking after this information then becomes one of making sure that the the verification queries are successful just when they should be. What does this entail? These are the main things that I am unclear about in this vision, and would be grateful to know. How do we use and transform personal information while retaining its verifiability? What is required to maintain that verifiability?

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