This book constitutes the thoroughly refereed post conference papers of the Third International Conference on Blockchain and Trustworthy Systems, Blocksys 2021, held in Guangzhou, China, in August 2021.The 38 full papers and the 12 short papers were carefully reviewed and selected from 98 submissions. The papers are organized in topical sections: Contents Blockchain and Data Mining; Performance Optimization of Blockchain; Blockchain Security and Privacy; Theories and Algorithms for Blockchain; Blockchain and Internet of Things; Blockchain and Smart Contracts; Blockchain Services and Applications; Trustworthy System Development. weiterlesen