I do not know of an open source library that uses the approach that I discussed in the article. Maybe there is one now. I was pulled away from the blockchain project to work on the more general problem of how to integrate Web services with financial services. Most of the blockchain implementations have a consensus phase where they use a distributed process to decide how to make a block. This makes them slow and expensive. My current thinking is that we should make a high volume “message oriented” system that skips consensus and instead uses a “trust but verify” approach. It would process messages and emit blocks from some centralized cloud system, and users could verify in real time that the blocks contain the right data. If you take this approach, you can just piggyback on replicated cloud services like Google PubSub, Google Dataflow, and Google Bigtable. You have to add your own encryption and identity management. But, it’s a manageable way to get a very high volume signed data flow.