This book constitutes the refereed proceedings of two workshops held at the 23rd International Conference on Financial Cryptography and Data Security, FC 2019, in St. Kitts, St. Kitts and Nevis, in February 2019.The 20 full papers and 4 short papers presented in this book were carefully reviewed and selected from 34 submissions.The papers feature the outcome of the 4th Workshop on Advances in Secure Electronic Voting, VOTING 2019 and the Third Workshop on Trusted Smart Contracts, WTSC 2019. VOTING covered topics like election auditing, voting system efficiency, voting system usability, and new technical designs for cryptographic protocols for voting systems.WTSC focuses on smart contracts, i.e., self-enforcing agreements in the form of executable programs, and other decentralized applications that are deployed to and run on top of (specialized) blockchains.

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, Curacao, 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 onSecure 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.

This book constitutes the refereed proceedings of 5 workshops held at the 21st International Conference on Financial Cryptography and Data Security, FC 2017, in Sliema, Malta, in April 2017.The 39 full papers presented were carefully reviewed and selected from 96 submissions. They feature the outcome of the 5th Workshop on Encrypted Computing and Applied Homomorphic Cryptography, WAHC 2017, the 4th Workshop on Bitcoin and Blockchain Research, BITCOIN 2017, the Second Workshop on Secure Voting Systems, VOTING 2017, the First Workshop on Trusted Smart Contracts, WTSC 2017, and the First Workshop on Targeted Attacks, TA 2017.The papers are grouped in topical sections named: encrypted computing and applied homomorphic cryptography; bitcoin and blockchain research; advances in secure electronic voting schemes; trusted smart contracts; targeted attacks.