[TallGuyShort]

I don't. Hadn't even heard of Dunbar's Number and had to Google it :) I would imagine, though this is pure speculation, that it's highly variable and hard to measure accurately since most leaks are hard to pinpoint. Probably depends on company culture, nature of the deal, etc. I just think that if you're at the scale that verbally confirming who has dialed in via insecure means is unscalable, you're likely enough to be past this limit that you should be taking other countermeasures anyway.

[mmt]

> hard to measure accurately since most leaks are hard to pinpoint.

Pinpointing the source isn't necessary, though, only knowing that the leak occurred and the approximate number of people "in on it". Even limiting this to leaks to the media for information shared at company meetings (so the number of people is equal to the number of employees) could provide interesting data, assuming a large enough sample size (and that leaks are numerous enough).