This book constitutes the refereed proceedings of 3 workshops held at the 22nd International Conference on Financial Cryptography and Data Security, FC 2018, in Nieuwport, Curaçao, in March 2018. The 23 full papers presented together with 2 short papers were carefully reviewed and selected from 52 submissions. They feature the outcome of the 5th Workshop on Bitcoin and Blockchain Research, BITCOIN 2018, the Third Workshop on Secure Voting Systems, VOTING 2018,and the Second Workshop on Trusted Smart Contracts, WTSC 2018. The papers are grouped in topical sections named: Blockchain, Distributed Ledgers, Cryptography, Bitcoin, Voting, and Smart Contracts.