  Permissionless blockchains (e.g., Bitcoin, Ethereum, etc) have shown a wide
success in implementing global scale peer-to-peer cryptocurrency systems. In
such blockchains, new currency units are generated through the mining process
and are used in addition to transaction fees to incentivize miners to maintain
the blockchain. Although it is clear how currency units are generated and
transacted on, it is unclear how to use the infrastructure of permissionless
blockchains to manage other assets than the blockchain's currency units (e.g.,
cars, houses, etc). In this paper, we propose a global asset management system
by unifying permissioned and permissionless blockchains. A governmental
permissioned blockchain authenticates the registration of end-user assets
through smart contract deployments on a permissionless blockchain. Afterwards,
end-users can transact on their assets through smart contract function calls
(e.g., sell a car, rent a room in a house, etc). In return, end-users get paid
in currency units of the same blockchain or other blockchains through atomic
cross-chain transactions and governmental offices receive taxes on these
transactions in cryptocurrency units.
