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Ethan Heilman

TumbleBit: An Untrusted Bitcoin-Compatible Anonymous Payment Hub
Ethan Heilman

TumbleBit is a new anonymous payments protocol that is fully
compatible with today’s Bitcoin protocol. TumbleBit allows parties to
make payments through an untrusted Tumbler. No-one, not even the
Tumbler, can tell which payer paid which payee during a TumbleBit
epoch. TumbleBit consists of two interleaved fair-exchange protocols
that prevent theft of bitcoins by cheating users or a malicious
Tumbler. TumbleBit combines fast cryptographic computations (performed
off the blockchain) with standard bitcoin scripting functionalities
(on the blockchain) that realize smart contracts. TumbleBit was used
to mix 800 input addresses to 800 output addresses on Bitcoin’s
blockchain.