## 4 The Proposed Scheme
### Privacy-Preserved Security Energy Trading
#### 4.2.4 Transaction
Finally, both parties encrypt the account balance and send it to KGC. After passing the verification \(\beta=M_{5}\times M_{6}\), KGC forwards the encrypted transaction data to the transaction broadcast. Figure 5: Relationship between chain data and cloud data. Figure 6: Overall flow of transactions. ing node, and the transaction is completed. The above process does not require the private keys of both parties to decrypt any encrypted data. When the homomorphic decryption key is unknown, the transaction amount and account balance cannot be decrypted

### Anonymity Analysis

After registering with the energy station, all users can become legitimate energy nodes, and all energy nodes can request a pseudonym from KGC before engaging in trading. The node utilizes the pseudonym that KGC creates for it to carry out energy transactions. The method put forward in this study makes use of IBS technology specified in the Chinese national standard SM9 [28] issued by the China National Cryptology Administration to generate pseudonyms for nodes. The identity password security of bilinear pairs serves as the foundation for the algorithm's security, including the problem of solving discrete logarithms on elliptic curves. The calculation process of anonymous identities includes a one-way algorithm of hash functions. Therefore, it is not feasible to crack the password. The anonymity of the proposed scheme is guaranteed. ### Traceability of Pseudonyms

In the process of pseudonym application, the KGC stores the agreement between the node's true identity and its pseudonym in the local list. If any dispute occurs in the transaction process, the disputing party can send an arbitration application to the KGC. The KGC can query the local list to resolve the real identity of the node and gradually trace the transaction process. ### Scheme Comparison

The comparison between the plan put forward in this study and previous works is shown in Figure 4.0 [PERSON] et al. [1] and [PERSON] et al. [10] have built their own transaction frameworks through the alliance blockchain. These two systems make the guarantee that the data are safe, but saving all the trading data on the chain will lead to large storage overhead. The confidentiality and transparency of energy trading are guaranteed by the blockchain-based energy trading privacy protection method developed by [PERSON] et al. [8], but the system's overall computation and storage overhead are high. In the scheme of [20], the blockchain-based cross-domain Industrial Internet of Things device authentication scheme proposed, they use IBS technology to provide anonymous identified for entities, but it does not take into account the privacy leakage problem that may be caused in the process of entity interaction. In the scheme of [21], through the system's integration of blockchain and multi-signature technologies, peers can securely conduct transactions while negotiating energy rates in an anonymous manner. However, due to the redundancy of communication messages and insufficient routing, the system has scalability problems. In the scheme of [22], the nodes in the blockchain transaction have their identities protected using an upgraded identity-based group signature technique; however, the privacy disclosure of transaction data is also not taken into account. Ref. [23] proposes a framework to hide the amount by encrypting and decrypting using a homomorphic encryption cryptosystem, which can realize the encryption of the transaction amount, but cannot meet the needs of users for identity privacy. In this study, users' identity privacy and transaction information privacy are protected using a transaction mechanism based on IBS and Paillier homomorphic encryption. Both the node identity and transaction amount privacy are safeguarded during the transaction procedure. Additionally, with the help of the cloud, the amount of redundant data written to the blockchain is decreased.