# Comparative Study of Blockchain Hashing Algorithms with a Proposal for HashLEA
## 2 Related Works
The authors draw the conclusion that it is more challenging to compromise on hiding and puzzle-friendliness than on preimage resistance. This suggests that hash functions like SHA-256, which are preimage-resistant, are suitable for blockchain security. This theoretical framework provides insights into potential vulnerabilities and attacks on blockchain hash functions. [PERSON] et al. [37] examine the significance of hash functions in blockchain systems, which guarantees data integrity and transaction speed. The efficiency of the hash algorithm is of paramount importance for the maintenance of stability and the facilitation of rapid transactions. The acceleration of hash functions enhances the operational efficiency of blockchain systems by expediting the processing of transactional data. The research tests a variety of hash functions within a straightforward blockchain framework, demonstrating that the BLAKE2b algorithm is particularly adept at processing data rapidly and efficiently on hardware, while the SHA family of algorithms strikes a balance between complexity and security. [PERSON] et al. [38] investigate the potential for integrating blockchain technology with Industrial IoT (IIoT) in order to enhance data integrity and network efficiency. They propose a flexible blockchain architecture that adapts the hash function used for mining based on transaction volume, aiming to enhance the availability of the blockchain network. The selection of lightweight hash functions, including QUARK, PHOTON, and SPONGENT, ensures that the architecture exhibits high performance in terms of area, throughput, and power consumption, rendering it suitable for resource-constrained IIoT devices. The authors argue that this dynamic approach mitigates the computational load and latency, thereby enhancing scalability and efficiency, particularly in the context of monitoring and supervision applications within IIoT environments. [PERSON] et al. [39] address the challenges of efficiency and computational overhead in blockchain data verification, particularly in Ethereum, by proposing a novel aggregation scheme for zero-knowledge proofs within Merkle Trees. The approach proposed by the authors markedly reduces the size of the proof and the computational resources required for verification, thereby achieving a balance between security and efficiency. The results of experimental evaluations conducted using actual Ethereum block data demonstrate a notable enhancement over traditional methods. This work offers a scalable and secure solution for blockchain data verification, thereby enhancing the performance and adaptability of blockchain technology across a range of applications, including financial transactions and supply chain management. In addition to the studies examining the hash algorithms developed for blockchain applications mentioned above, many new hash algorithm architecture designs [40; 41], new hash functions [42; 43], and hash-based blockchain applications [44; 45] have been presented. In addition to the studies mentioned earlier, the key hash functions discussed in the literature are presented in detail in the following sections. Existing lightweight hash functions have demonstrated notable success and offered application-specific advantages in IoT-blockchain integration. However, challenges such as high computational complexity, energy consumption, and compatibility with resource-constrained IoT devices remain areas of concern. While these algorithms have their strengths, the proposed HashLEA algorithm has been designed to address these limitations by focusing on speed, performance, and security. Our evaluations indicate that HashLEA performs faster and more efficiently than the reviewed algorithms while maintaining a comparable level of security, making it a competitive option for IoT-blockchain applications. The contributions of the HashLEA algorithm are explained in detail below.