This dissertation explores the impact of quantum computing on UTXO-based blockchains like Bitcoin, presenting two significant contributions to the field. The primary contribution introduces two novel cryptographic schemes designed to securely transition from current cryptographic mechanisms to quantum-resistant alternatives. These schemes focus exclusively on the signature verification process, ensuring compatibility with all transaction types, including multi-signature transactions.
The first scheme is highly efficient, requiring minimal changes to Bitcoin’s codebase—fewer than 100 lines in the proof-of-concept implementation. The second scheme, while more complex, incorporates symmetric encryption and decryption algorithms. This allows users to customize security parameters based on their risk perception and asset value, providing a flexible transition strategy.
The secondary contribution involves an empirical analysis of the financial risks posed by quantum-capable adversaries. This dissertation evaluates how advancements in quantum computing could compromise the cryptographic foundations of blockchains and quantifies the potential for value extraction by quantum attackers under existing security frameworks.
In summary, this research identifies and quantifies the risks introduced by quantum advancements and proactively proposes strategic approaches to fortify decentralized blockchain systems in preparation for the quantum era. By addressing both the technical transition to quantum-resistant cryptography and the associated financial risks, the dissertation offers a comprehensive framework for enhancing the security and resilience of UTXO-based blockchains against future quantum threats.