Patent attributes
Disclosed is a system to efficiently compute validity of a block chain controlling access to an encrypted data. The block chain defines user permissions to access the encrypted data. The system creates a computational checkpoint proving a validity of the block chain based on the user permissions defined in the block chain. The system performs an expensive computation from an initial block in the block chain to a last block in the block chain, wherein the expensive computation validates each block between the initial block and the last block. The system creates a proof of the validity of the block chain based on the expensive computation and stores the proof after the last block in the block chain. The system can provide the proof of the validity, without performing the expensive computation, where verifying the proof is at least ten times faster than the expensive computation.
