ADR 040 and hash collisions

[peterbourgon]

B2: hash(key) → key: a reverse index to get a key from an SMT path. Internally the SMT will store (key, value) as prefix || hash(key) || hash(value). So, we can get an object value by composing hash(key) → B2 → B1.

What happens when two distinct keys yield the same hash?