You can do a BTC transaction without connecting to the internet. A new concept HTLBs which are very similar to HTLCs. Removing the "reject" message to clean up some code. Discussion on SIGHASH_NOINPUT's safety.
Off Chain and Programming Blockchain:
I spoke a few times at SXSW, but the videos aren't online. Tech Talk Q&A video. My book is available in print on Amazon! Programming Blockchain is coming to New York!