(inspired + extract from Calypso paper)
Auditability: All data accesses are third-party verifiable and recorded in a tamper-resistant log.
Decentralization: There are no single points of availability failure or security compromise in the system.
Confidentiality: Secrets stored on-chain can be decrypted only by authorized clients after leaving an access record.
Fair access: Clients are guaranteed authorized access to a secret after posting a valid access request on-chain. If a barrier point exists, authorized clients atomically get simultaneous access after the barrier, protecting against front-running.
Future: Receiver anonymity: An on-chain proof-of-access log does not identify the user unless an audit is requested.
Future: Dynamic self-sovereign identities: Users and organizations fully control the public keys representing their identities, and can update them verifiably and atomically.
(Generalization of the above^)
Organization A wants to share with organization B a document D whose entirety or certain parts are classified and should be accessible only by people with proper clearance. Clearance is granted to (or revoked from) employees individually as needed or automatically when they join (or leave) a depart- ment, so the set of authorized employees continuously changes. The goal is to enable the mutually distrustful A and B to share D while dynamically enforcing the specific clearance requirements and securely tracking accesses to D for auditing