Hi there,

I got some requests to re-record the tutorial talk I gave at DevCore 2015, "How to build a timestamping smart contracts app in 30 minutes". It's now available here:

    https://bitcoinj.github.io/document-timestamp-app

It covers:
  • How to customise the wallet-template app for this use case
  • How to construct a complex multi-stage SPV proof of block chain inclusion
  • How to save and then verify proof files
  • How to bind transaction confidence state to the user interface
  • How to create a Mac DMG bundle with a custom icon
I hope someone finds it enjoyable!



On Thu, Apr 9, 2015 at 10:23 PM, Mike Hearn <mike@plan99.net> wrote:
Next week on April 15th Gavin, Wladimir, Corey and myself will be at DevCore London:


If you're in town why not come along?

It's often the case that conferences can be just talking shops, without much meat for real developers. So in the afternoon I'll be doing two things:
  1. Running a hackathon/workshop type event. The theme is contracts, but we can hack on whatever you all feel like.

  2. My "talk" will actually be a live coding event. Writing contracts apps has become a lot easier in the past few years, and to prove it to you I will write a decentralised cross-platform Tor supporting document timestamping app that uses OP_RETURN outputs and has a nice GUI ..... in 30 minutes, on stage.

    Don't think it can be done? Turn up and see for yourself. 
See you there!