Revisited—The Subliminal Channel in Blockchain and Its Application to IoT Security

Abstract

Although digital signature has been a fundamental technology for cryptosystems, it still draws considerable attention from both academia and industry due to the recent raising interest in blockchains. This article revisits the subliminal channel existing digital signature and reviews its abuse risk of the constructor’s private key. From a different perspective on the subliminal channel, we find the new concept named the chamber of secrets in blockchains. The found concept, whereby the secret is hidden and later recovered by the constructor from the common transactions in a blockchain, highlights a new way to encourage implementing various applications to benefit efficiency and security. Thus, the proposed scheme benefits from the following advantages: (1) avoiding the high maintenance cost of certificate chain of certificate authority, or public key infrastructure, and (2) seamlessly integrating with blockchains using the property of chamber of secrets. In order to easily understand the superiority of this new concept, a remote authentication scenario is taken as a paradigm of IoT to demonstrate that the further advantages are achieved: (1) avoiding high demand for storage space in IoT devices, and (2) avoiding maintaining a sensitive table in IoT server.