An efficient consortium blockchain privacy protection scheme based on group signatures and bulletproofs

Compared to the public blockchain, the consortium blockchain restricts nodes’ read and write permissions; however, in the transaction transfer process, the ledger is transparent to all parties involved, and research continues to focus on the security of private data during the transaction. Most current blockchain privacy protection schemes concentrate on protecting the transaction amount’s privacy, but the issue of identify exposure of both parties during the transaction process has not received enough attention, and the transaction legitimacy verification strategy may lead to inadequate security due to the use of ineffective cryptographic algorithms. This paper proposes a scheme for blockchain privacy protection based on group signatures and bulletproofs (BPPGSB). To guarantee that the identities of both parties are hidden from the common nodes, verifiable to the verification nodes, and traceable to the group administrator nodes, the ElGamal algorithm on elliptic curves (EC-ElGmal) is employed to process and improve interaction processes that may reveal identity information in the original group signature scheme. Meanwhile, the bulletproofs, a zero-knowledge proof algorithm based on Pedersen commitment, is developed to validate the transaction legitimacy process both comprehensively and effectively. Together with the whole validation strategy for the transaction with a transaction amount greater than zero and transaction balance greater than or equal to zero, the verification process ensures no exposure of the actual transaction data involved in the transaction. The experimental results indicate that, compared to the current scheme, the entire transaction process can hide the identities and transaction details of the two parties involved in the transaction, the transaction validation algorithm is more effective, and the validation strategy is more comprehensive. Also, the running time of our approach is less than existing privacy protection schemes.