[Cryptography] Size of the PGP userbase?

[Phil Pennock]

On 2013-12-11 at 08:51 -0500, Phillip Hallam-Baker wrote:
> I am trying to get an estimate of the size of the PGP userbase for a
> presentation. Does anyone have figures?

You're probably after Strong Set figures, which are the keys which are
usefully verifiable, although this ignores isolated islands, such as
companies with strong internal cross-signatures and no attempts to join
the Strong Set.

http://pgp.cs.uu.nl/plot/

About 53,000 keys are in the Strong Set.

 * "The PGP web of trust can be viewed as a directed graph where the
   points are the PGP keys, and the arrows (directed lines) are the
   signatures."
 * "The strong set is the largest set of keys such that for any two keys
   in the set, there is a path from one to the other."

The active userbase will additionally include those who have no
cross-signatures, whether because the do understand the trust models and
just want a persistent identifier (but not a real-world-name-mapping
verifiable one) or, more commonly, because they don't understand.

-Phil