Explain that the hybrid key store is the historical implementation and
neither alternative is a drop-in replacement. Discuss how we could
potentially reduce the number of variants after the next major release.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
In particular, fix an off-by-one error right after I explain how the number
is off by one from what you'd expect. State explicitly that the number can
be negative.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
