Brands' private credentials

[Jason Holt]

Here's what I remember from about a year ago about the current state of
private credentials.  That recollection comes with no warranties express or
implied.

Last I heard, Brands started a company called Credentica, which seems to only
have a placeholder page (although it does have an info@ address).

I also heard that his credential system was never implemented, but that might
be wrong now.  Anna Lysyanskaya and Jan Camenisch came up with a credential
system that I hear is based on Brands'. Anna's dissertation is online and
might give you some clues.  They might also have been working on an
implementation.

I came up with a much simpler system that has many similar properties to
Brands', and even does some things that his doesn't.  It's much less developed
than the other systems, but we did write a Java implementation and published a
paper at WPES last year about it.  I feel a little presumptuous mentioning it
in the context of the other systems, which have a much more esteemed set of
authors and are much more developed, but I'm also pretty confident in its
simplicity.

http://isrl.cs.byu.edu/HiddenCredentials.html
http://isrl.cs.byu.edu/pubs/wpes03.pdf

Note that most anonymous credential systems are encumbered by patents.  The
implementation for my system is based on the Franklin/Boneh IBE which they
recently patented, although there's another IBE system which may not be
encumbered and which should also work as a basis for Hidden Credentials.

					-J


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