Multi-core and SIMD Architecture Based Implementation on SHA-256 of Blockchain

SHA-256 is a completely unpredictable pseudorandom function which generates unique output for a given input ensuring data authenticity and non-repudiation. It is the cornerstone for imparting security and privacy into Blockchain and its efficiency of calculation decides the performance of Blockchain. In this paper, we propose two novel methods to accelerate the calculation of SHA-256 in different situations. To eliminate the useless operations, we present pre-expanded padding blocks and hard coded into the software. On this basis, for a single message containing multiple 512-bit message blocks, we propose Interleaved Multi-Vectorizing Message Scheduling (IMV-MS) to optimize the message schedule stage of SHA-256, which utilize the interleaved multi-vectorizing (IMV) to combine single instruction multiple data (SIMD) vectorization with SHA-256. It splits a vectorized program into multiple states, then it interleaves the execution of vectorized states from those running instances which can make full use of the data parallelism in SIMD. On the other hand, in the situation where we hash several messages simultaneously, we propose the modified SHA-256 which employs SIMD instructions and thread-level parallelism technology together to realize parallel optimization on SHA-256. As experimental results show, IMV-MS and the proposed SHA-256 achieves up to 6.36X, 60.38X better performance compared with the pure SIMD vectorization and the pure scalar implementation, respectively.