Trust, was Re: SEIS: Re: A $25,000,000,000 PKI

[Ed Gerck <egerck@xxxxxxxxxx>]

Patrik Fältström wrote:

> It is also the case that if you also have a contract between the
> parties exchanging information, or for example the party which hands
> out the keys, things get extremely complicated -- and I have not seen
> a single person being able to come with a formula for "TRUST" ever,
> and I doubt anyone will.

See:

1. Ed Gerck, "Towards Real-World Models of Trust: Reliance on Received
Information", in http://www.mcg.org.br/trustdef.htm

2.  Ed Gerck, "Trust Points" from http://www.mcg.org.br/trustdef.txt excerpted in
"Digital Certificates: Applied Internet Security" by J. Feghhi, J. Feghhi and P.
Williams, Addison-Wesley , ISBN 0-20-130980-7, p. 194-195, 1998.

3. John Gregory, "Electronic Legal Records: Pretty Good Authentication?", in
http://www.callacbd.ca/summit/auth-johngregory.html

4. Lea Viljanen, with Web page at  http://www.nixu.fi/~lea/  in a paper delivered
in an Internet seminar in Finland, had the following excerpt which may well
illustrate the usefulness of the approach in [1] above:

"If we analyze the first case following Gerck's definition of trust
being "[that which is] essential to a communication channel but which cannot
be transferred from the source to a destination using that channel"
(see 2.2 ), we must first analyze what is the communication channel in
this case. Here we find that the certificates themselves are the
channel/medium with which the data conveying some trust expressions are
transmitted. So trust to the certificates themselves cannot be
transferred using the certificates.

To define trust in a communication system from this point of view also
yields the interesting point that we can have several trust requirements
for a communication system. Each observer can have a list of trust
requirements for every level of the communication system, for example
trust for the hardware, trust only data carried by operator X or only
within our own corporate network, trust only data-origin-authenticated
messages etc. For us to trust the information received from the
communication all these trust conditions must be satisfied. The
existence of these multiple layers of trust is usually ignored."


Cheers,

Ed Gerck