Lazy revocation

Plutus allows owners of files to revoke other people's rights to access those files. Following a revocation, we assume that it is acceptable for the revoked reader to read unmodified or cached files. A revoked reader, however, must not be able to read updated files, nor may a revoked writer be able to modify the files. Settling for lazy revocation trades re-encryption cost for a degree of security. We elaborate on lazy revocation in Section 3.4.