A secure data system facilitates efficient searching of extensive data storage layers, e.g., a blockchain. The system may create an index for data elements of a predefined type recorded in the blockchain. The system may generate the index by invoking executable instructions stored in an executable data element (e.g., a smart contract) recorded in the blockchain and associated with the predefined type of data elements. The index facilitates fast query into the blockchain for the data elements of the predefined type.