The purpose of a hash serves to avoid hash collisions due to equal encodings for different objects. It is in general not possible to derive the purpose of the hash from the hash alone.

Whenever a hash is computed using HashOps, a HashPurpose must be specified that gets included in the hash. To reliably prevent hash collisions, every HashPurpose object should be used only in a single place.

All HashPurpose objects must be created through the HashPurpose$.apply method, which checks that the id is fresh.