Document security issues around selection of commitment tree root for senders and receivers. about zips HOT 7 CLOSED

This needs to be on the protocol spec, but it doesn't influence our protocol or our codebase, so let's move it to the spec repo (zips). ping @daira

from zips.

This is largely covered by zcash/zcash#604 is it not?

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@ebfull I want zcash/zcash#604 to be closable by making the spec reflect the current implementation. This ticket is about analysing whether that's a good idea and whether we want to change the decision, and/or make recommendations to wallet implementors.

from zips.

@daira why is this on the agenda? Are we doing in-or-not-1.0 triage?

from zips.

The discussion in https://github.com/#comment-289658016 and subsequent comments should form the basis of this documentation.

from zips.

See also zcash/zcash#1614 and the links from it.

from zips.

Duplicate of #351.

from zips.