| Abstract [eng] |
This doctoral dissertation addresses a pressing challenge in private blockchain technologies: how to effectively reconcile transaction authenticity, user anonymity, and the requirements for independent auditing and regulatory compliance. Conventional approaches, such as Monero’s Linkable Spontaneous Anonymous Group (LSAG) signatures, provide a degree of anonymity but often incur high computational costs and struggle to balance confidentiality with the demands of external oversight. The primary aim of the research is to develop and investigate an integrated Transaction Authenticity and Anonymity System (TAAs) suitable for resource-constrained environments, including the Internet of Things (IoT). The proposed system employs additively-multiplicatively homomorphic ElGamal encryption within the Unspent Transaction Output (UTXO) paradigm. This enables network participants and audit authorities to verify transaction balance correctness without revealing actual amounts. Anonymization and deanonymization are achieved through Schnorr multi-signatures. In addition, the alternative method of anonymization based on Schnorr type signature realized by Matrix Power Function (MPF) is presented having a potential to be a hypothetic post-quantum cryptographic method. Theoretical analysis and experimental evaluations demonstrate that the TAAs system significantly outperforms Monero LSAG ring signatures in terms of operational efficiency and execution time, particularly as the number of participants increases. Practical implementations in a simulated private blockchain and a hybrid IoT confirm the system’s functionality under realistic conditions. The proposed methods maintain high security levels while minimizing computational and energy demands on constrained devices. |
