Efficient Hash-Based Redactable Signature for Smart Grid Applications

The sharing of energy usage data in smart grids is becoming increasingly popular because it not only allows different entities to access fine-grained energy consumption data but also improves the effectiveness of smart grid technologies. How to ensure both verifiability and privacy of the shared data is a vital issue. Most existing privacy-preserving authentication schemes greatly hinder the flexibility of sharing data among multiple parties due to vulnerability and inefficiency reasons. The customer-centric energy usage data management framework based on redactable signature (RS) technology can be seen as an effective solution. It offers customers the flexibility to remove parts of privacy-sensitive data depending on different data usage demands, and ensures data verifiability for third party service providers. However, existing RS schemes are computationally inefficient for constrained devices such as smart meters. Besides, it is said that quantum computers are expected to break all traditional public-key primitives. In this regard, almost all existing RS schemes are vulnerable to quantum attacks. To address the above concerns, in this work, we propose a hash-based RS scheme HRSS based on a variant of the Goldreich-Goldwasser-Micali tree, a length-doubling pseudorandom generator, and an underlying SPHINCS+ framework. Our HRSS is the first quantum-safe RS scheme, where the security depends only on the security of underlying hash functions. We instantiate and evaluate the performance of our design. Theoretical and experimental comparisons with recent works show that HRSS is practical for smart grids.