  A term structure model in which the short rate is zero is developed as a
candidate for a theory of cryptocurrency interest rates. The price processes of
crypto discount bonds are worked out, along with expressions for the
instantaneous forward rates and the prices of interest-rate derivatives. The
model admits functional degrees of freedom that can be calibrated to the
initial yield curve and other market data. Our analysis suggests that strict
local martingales can be used for modelling the pricing kernels associated with
virtual currencies based on distributed ledger technologies.
