In recent years, blockchain technology has been used in many fields, including IoT and Smartphones. Since most of these devices are battery constrained and have low processing capabilities, conventional blockchains are not suitable for these types of systems. In this field, critical challenges that need to be addressed are providing security for transactions and power consumption. An available solution to meet the mentioned challenges is TrustChain. Unlike conventional blockchains, TrustChain does not have a single global chain. Instead, each node is responsible for building and maintaining its local chain. With all the benefits, TrustChain is vulnerable to the whitewashing attack and suffers from client vulnerability issues. Moreover, once a fatal error occurs, the recovery time of each TrustChain node is considerably high. In this paper, we propose a solution to address the attacks mentioned above by implementing an authentication system with MongoDB on top of TrustChain. Moreover, we connected TrustChain to the distributed cloud storage to significantly reduce the recovery time of nodes in fatal errors (up to 80%). Finally, we evaluate improved TrustChain with the PoW-based smartphone-oriented blockchains from two aspects of security and power consumption, proving that improved TrustChain does not significantly affect the lifetime of the smartphone battery. Its power consumption is less than mentioned blockchains and is more secure than these systems against main attacks.

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