A Google engineer has released an open source Java client for Bitcoin, the peer-to-peer currency that may eventually revolutionize online transactions. Although we have discussed the Bitcoin project previously (see Digital currency lets GPU cycles print money) it isn't yet a familiar idea. Fortunately there is now a YouTube video addressing the question What is Bitcoin: So as far as the end user is concerned Bitcoin makes it much easier to make handle low-value transations online as it eliminates fees and chargebacks and should make payments quick and easy. From a technical point of view it is a digital currency sytem consisting of an open source client and P2P network. However to make it all a reality requires rather a lot of developer effort and as an open source project this relies on volunteers. So the news that an engineer has developed BitCoinJ, a Java client that implements the simplified payment verification mode proposed by Satoshi Nakamoto, the founder of Bitcoin, is welcome news. His affilaition with Google is an added advantage but BitcoinJ isn't an official Google project but one undertaken in the 20% of time Google allows its staff to spend on personal projects. BitCoinJ has full documentation and some example apps showing how to use the library. The project aims to be easier to understand than the C++ implementation, and be suitable for usage on constrained devices such as mobile phones. More information: bitcoinj project page Digital currency lets GPU cycles print money Bitcoin website Wikipedia Bitcoin entry Satoshi Nakamoto's original paper describing Bitcoin: Bitcoin: A Peer-to-Peer Electronic Cash System