Alternative/additional verification methods

When talking to other people, trying to convince them to use Matrix/Element, the verification process is always declared as being too complicated. I would therefor like to propose two alternative (or even complementing), opt-in verification methods:

The first one would simply be TOFU (Trust On First Use): In many cases I have seen, peers first talked to each other about opening a personal chat in Matrix, so that it's clear who the other person is when an invitation arrives. So the other end could simply accept that invitation w/o further verification.

The other method would be a (probably anonymized, hidden) web of trust (WoT). Given that A and B, as well as B and C already know (have verified) each other, A and C could verify each other by asking their common contact B (eventually w/o telling them who the common contact is) under the hood. The more common contacts can be asked, the better. Of course, the common contact(s) should have enabled WoT, too.

Users should then have the choice of enabling WoT with either TOFU or the traditional verification method being the fallback in case no common contacts are found.

Thoughts?

Start by reviewing the existing Matrix verification process and the two proposed alternatives in this issue. Determine whether TOFU or a web of trust belongs in the Matrix specification, what protocol behavior would need to be defined, and what a concrete, agreed scope would be before implementation.

Written by the indexing model from the issue text.