Trusted Third Party Application in Durable Medium e-Service

The paper presents a novel concept of applying a trusted third party (TTP) to the blockchain-based electronic service (e-service) in the form of a durable medium. The main aim of the proposed e-service is storing, managing, and processing sensitive electronic documents. The developed e-service meets the requirements of both Polish law (related to the durable medium) and market needs. Firstly, the functional requirements were defined. Subsequently, the adequate e-service was designed, and then implemented in a real company in Poland. Due to the nature of the durable medium e-service, the presented research combines scientific and implementation aspects. The designed and implemented e-service is secure (because of using the immutable blockchain technology merged with symmetric and asymmetric cryptographic algorithms) and trusted (by using TTP as the e-service provider, as well as an independent arbitrator monitoring the document storage and processing flow). Finally, the presented approach was experimentally verified using Hyperledger Besu—a blockchain implementation platform. During the realization of two designed test scenarios, over 30,000 transactions were added to the blockchain. Furthermore, security analyses were performed regarding inherent blockchain properties, the use of cryptographic algorithms, and potential cyberattacks and vulnerabilities.