  Banking as an essential service can be hard to access in remote, rural
regions where the network connectivity is intermittent. Although micro-banking
has been made possible by SMS or USSD messages in some places, their security
flaws and session-based nature prevent them from a wider adoption. Global level
cryptocurrencies enable low-cost, secure and pervasive money transferring among
distributed peers, but are still limited in their ability to reach more people
in remote communities.
  We proposed to take advantage of the delay-tolerant nature of blockchains to
deliver banking services to remote communities that only connect to the broader
Internet intermittently. Using a base station that offers connectivity within
the local area, regular transaction processing is solely handled by blockchain
miners. The bank only joins to process currency exchange requests, reward
miners and track user balances when the connection is available. By
distributing the verification and storage tasks among peers, our system design
saves on the overall deployment and operational costs without sacrificing the
reliability and trustwor- thiness. Through theoretical and empirical analysis,
we provided insights to system design, tested its robustness against network
disturbances, and demonstrated the feasibility of implementation on
off-the-shelf computers and mobile devices.
