Tumblebit Server Demo

Use at your own risk.

About tumblebit.network

tumblebit.network is a classic Bitcoin tumbler, mixing together the transfer of one bitcoin from each of n distinct payers (Alice) to n distinct payees (Bob). TumbleBit is run with the payment phase shrunk to 30 seconds, so the protocol runs in epochs that require two blocks added to the blockchain. tumblebit.network provides k-anonymity within an epoch: no one, not even the Tumbler, can link one of the k transfers that were successfully completed during the epoch to a specific pair of payer and payee (Alice, Bob).

No Coordination
If Alice wants to pay Bob, she need not interact with any other TumbleBit users. Instead, Alice and Bob need only interact with the Tumblebit server and each other.
Bitcoin Compatibility
TumbleBit is fully compatible with the Bitcoin protocol. Bitcoin scripts are used to validate the preimage of a hash and to validate an ECDSA signature on a Bitcoin transaction.
Performance
Performance is limited only by the time it takes for two blocks to be confirmed on the blockchain and the time it takes for transactions to be confirmed; this takes approximately 20 minutes. Meanwhile, off-blockchain payments can complete in seconds.

Tumblebit Protocol Overview

TumbleBit replaces on-blockchain payments with off-blockchain RSA-puzzle solving, where Alice pays Bob by providing Bob with the solution to a blinded RSA-puzzle. The puzzle z is generated through interaction between Bob and Tumbler (the Tumblebit server) , and solved through an interaction between Alice and Tumbler . Each time a puzzle is solved, 1 bitcoin is transferred from Alice to the Tumbler and finally on to Bob.

Tumblebit overview

Tumblebit: An Untrusted Bitcoin-Compatible Anonymous Payment Protocol

This paper, authored by Ethan Heilman, Leen AlShenibr, Foteini Baldimtsi, Alessandra Scafuro and Sharon Goldberg, presents TumbleBit, a new uni- directional unlinkable payment protocol that is fully com- patible with today’s Bitcoin protocol. TumbleBit allows parties to make fast, anonymous, off-blockchain payments through an untrusted intermediary called the Tumbler: no one, not even the Tumbler, can link a payment from its payer to its payee. Every payment made via TumbleBit is backed by bitcoins, and comes with a guarantee that Tumbler can neither violate anonymity, nor steal bitcoins, nor “print money” by issuing payments to itself.

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