Note: we are at MadLab as usual, but this month’s meetup is on the Tuesday to avoid the bank holiday. If you want to let us know you’re coming, you can sign up on our event link.

This month for Bitcoin Machester we are going to talk on the theme of privacy. Blockchain-based currencies as a public ledger can be read by anyone and this causes positive and negative effects.

We will report on two technologies designed to enhance privacy and how they work.

Confidential Transactions

Max will describe Confidential Transactions, a new more private type of transaction for Bitcoin. Confidential Transactions enable Bitcoin users to send transactions where the amount is kept private, but the ledger can still be used to validate that the total amount adds up.

Max will describe how this works, what benefits it has for privacy, and what trade-offs it makes in terms of transaction size and performance.

CoinJoin and coin mixing

Ash will describe CoinJoin, a more basic form of privacy (but already actively in use) that combines transactions from multiple users to make tracing the flow of money harder. He will explain how CoinJoin works and discuss its limitations.

Ash will look at two implementations of CoinJoin: JoinMarket for Bitcoin and DarkSend (to be rebranded PrivacyProtect) for Dash. With JoinMarket, bitcoin holders can earn a fee by depositing coins as mixing collateral on a JoinMarket server they contral. With PrivacyProtect/DarkSend, Dash users can mix coins through the Dash masternode network. We will compare the differences of the two systems.

Pizza & Pub

As always we’ll have sponsored pizza provided by one of the Bitcoin-accepting vendors.

Finally at around 9pm we’ll head to the pub, which is our new friend Terrace right next to MadLab.