Proposal and Evaluation of Safe and Efficient Log Signature Scheme for the Preservation of Evidence

In recent years, the requirements for the preservation of evidence have increased for important log data, such as the data in the planned common number identification system in Japan. One of the proposed evidence preservation methods, the hysteresis signature scheme, reflects previously summarized data with a new digital signature of the log data. However, it takes a long time for this scheme to verify signatures. Therefore, we propose a new hybrid signature scheme that is based on the existing united signature scheme and the hysteresis signature scheme. In evaluations under various conditions, we found that the hybrid signature scheme is the most efficient.