Amin Sakzad – FPPW: A Fair and Privacy-Preserving Watchtower For Bitcoin

In this talk, I will introduce FPPW, a new payment channel with watchtower scheme for Bitcoin. This new scheme provides fairness with respect to all channel participants including both channel parties and the watchtower. The watchtower in FPPW learns no information about the off-chain transactions and hence the channel balance privacy is preserved. As a byproduct, we also define the coverage of a watchtower scheme, that is the total capacity of channels that a watchtower can cover on a scale of 0 to 1, and show that FPPW’s coverage is higher than those of PISA and Cerberus. If time allows, I will discuss two other watchtowers Garrison and Daric with various other properties and try to formalise the definitions of payment channels and watchtowers.