"Quantum Prudent Contracts with Applications to Bitcoin"
Smart contracts are cryptographic protocols that are enforced without a judiciary.
Smart contracts are used occasionally in Bitcoin. Public quantum money improves upon cash we use today, yet the current constructions do not enable smart contracts.
I'll discuss quantum prudent contracts -- a non-trivial subset of the functionality that a network such as Bitcoin provides. Examples discussed include: multi-signature wallets in which funds can be spent by any 2-out-of-3 owners; restricted accounts that can send funds only to designated destinations; and "colored coins" that can represent stocks that can be freely traded, and their owner would receive dividends.
The solution has all the benefits of public quantum money: no mining is necessary, and the security model is standard (e.g., it is not susceptible to 51% attacks, as in Bitcoin).
Our construction can be used to upgrade the Bitcoin network to a quantum payment scheme. Notable advantages of this approach are: transactions are locally verifiable and without latency, the throughput is unbounded, and most importantly, it would remove the need for Bitcoin mining.