  This chapter contributes to evolving the versatility and complexity of
blockchain-enabled services through extending the functionality of
blockchain-enforced smart contracts. The contributions include: (i) a method
for automated management of contracts with hierarchical conditionality
structures through an hierarchy of intelligent agents and the use of
hierarchical cryptographic key-pairs; (ii) a method for efficient and secure
matching and transfer of smart- contract underlyings (entities) among disparate
smart contracts/subcontracts; (iii) a method for producing an hierarchy of
common secrets to facilitate hierarchical communication channels of increased
security in the context of smart contracts/subcontracts/underlyings; and (iv) a
method for building secure and optimized repositories through distributed hash
tables in the context of contracts/ subcontracts/underlyings. These methods
help providing services that allow both narrower and worldwide reach and
distribution of resources. The longevity of the blockchain technology is
achieved through continuous innovation. Blockchain-enabled services are
potentially an efficient, secure, automated, and cost-effective alternative or
complement to current service infrastructures in a range of domains (legal,
medical, financial, government, IoT).
