Transferable Anonymous Payments via TumbleBit in Permissioned Blockchains


We propose a modification to the TumbleBit protocol, the off-chain payment hub enabling anonymous transactions among users in the Bitcoin network. Specifically, we modify the first step of the protocol by making the tumbler node sending a P2SH transaction onthe blockchain claiming that any user can redeem 1 Bitcoin by providing a SHA-2 preimage of a value chosen by the Tumbler. We remark that our modification enables Bob to transfer its Bitcoin to a third user, and argue that this modified TumbleBit protocol could find applications in permissioned blockchains, for example in the context of anonymous payments between different banks or fintech companies.

Proceedings of the Second Distributed Ledger Technology Workshop, DLT@ITASEC 2019, Pisa, Italy, February 12, 2019.