Authenticated digital currency redaction with stronger privacy and usability

With the promotion of digital currency, how to effectively solve the authenticity, privacy and usability of digital currency issuance has been a key problem. Redactable signature scheme (RSS) can provide the verification of the integrity and source of the generated sub-documents and solve the privacy problem in digital currency by removing blocks from the signed documents. Unfortunately, it has not realized the consolidation of signed documents, which can not solve the problem of merging two digital currencies. Now, we introduce the concept of weight based on the threshold secret sharing scheme (TSSS) and present a redactable signature scheme with merge algorithm (RSS-MA) using the quasi-commutative accumulator. Our scheme can reduce the communication overhead by utilizing the merge algorithm when transmitting multiple digital currency signatures. Furthermore, this can effectively hide the scale of users' private monetary assets and the number of transactions between users. While meeting the three properties of digital currency issuance, in order to ensure the availability of digital currency after redacting, editors shall not remove the relevant identification information block form digital currency. Finally, our security proof and the analysis of efficiency show that RSS-MA greatly improves the communication and computation efficiency when transmitting multiple signatures.