This week we talk with John Fletcher from Cambridge Cryptographic, author of a paper on Risk Free Interest rates using blockchains.

We explore why this is an important economic control that is used by central banks, and why it is critical to the smooth operation of global economies.

We talk about proof of stake blockchains and their ability to produce risk free interest rates, and also about how proof of work blockchains can help provide the the sybil defense mechanism and anchor the value to a real world economic indicator, the cost of energy.