Quantum-secured blockchain
This addresses the problem of quantum threats to blockchain security for commercial and governmental applications, representing a novel solution rather than an incremental improvement.
The authors tackled the vulnerability of blockchain to quantum computer attacks by proposing and experimentally realizing a quantum-safe blockchain platform using quantum key distribution over an urban fiber network, achieving information-theoretically secure authentication.
Blockchain is a distributed database which is cryptographically protected against malicious modifications. While promising for a wide range of applications, current blockchain platforms rely on digital signatures, which are vulnerable to attacks by means of quantum computers. The same, albeit to a lesser extent, applies to cryptographic hash functions that are used in preparing new blocks, so parties with access to quantum computation would have unfair advantage in procuring mining rewards. Here we propose a possible solution to the quantum era blockchain challenge and report an experimental realization of a quantum-safe blockchain platform that utilizes quantum key distribution across an urban fiber network for information-theoretically secure authentication. These results address important questions about realizability and scalability of quantum-safe blockchains for commercial and governmental applications.