A Solution for Secure Certified Electronic Mail Using Blockchain as a Secure Message Board

The certified mail is a value-added service that is widely used in the paper world. However, the scientific community has not yet provided a solution for certified e-mail that has achieved widespread acceptance. This lack of a certified e-mail solution is not due to a lack of proposed approaches; because over the past 40 years, more than 100 protocols have been reported in journals and at conferences. The vast majority of these proposed protocols use a trusted third party (TTP) to achieve fairness. The few solutions without a TTP have not been successful due to their high computational and/or communication cost. Blockchain provides a new approach to develop the protocols without a TTP but without the prior drawbacks of the previous solutions without a TTP. Here, we present a new protocol for certified e-mail based on a blockchain without a conventional TTP that is integrated with the conventional e-mail infrastructure. The protocol is secure, efficient, and viable from a practical perspective.