  The Transport Layer Security (TLS) protocol and its public-key infrastructure
(PKI) are widely used in the Internet to achieve secure communication.
Validating domain ownership by trusted certification authorities (CAs) is a
critical step in issuing digital certificates, but unfortunately, this process
provides a poor security level. In this work, we present SmartCert, a novel
approach based on smart contracts to improve digital certificates. A
certificate in SmartCert conveys detailed information about its validation
state which is constantly changing but only with respect to the specified smart
contract code and individual domain policies. CAs issuing and updating
certificates are kept accountable and their actions are transparent and
monitored by the code. We present the implementation and evaluation of
SmartCert, and discuss its deployability.
