Fourth lecture of the Bitcoin and cryptocurrency technologies online course.

For the accompanying textbook, including the free draft version, see: bitcoinbook.cs.princeton.edu/

In this lecture (click the time to jump to the section):
* Simple Local Storage 0:27
* Hot and Cold Storage 6:28
* Splitting and Sharing Keys 19:52
* Online Wallets and Exchanges 30:54
* Payment Services 50:17
* Transaction Fees 58:30
* Currency Exchange Markets 1:04:09