This book constitutes the proceedings of the workshops that have been held in conjunction with the 28th International Conference on Financial Cryptography, FC 2024, which took place in Willemstad, Curaçao, during March 4-8, 2024. 
The total of 23 papers included in this book stem from the following workshops: 

• 9th Workshop on Advances in Secure Electronic Voting Schemes (Voting 2024), focusing on secure voting protocols, has accepted 5 papers out of 13 submissions;
• 4th Workshop on Decentralized Finance (DeFI 2024), focusing on decentralized finance and a blockchain powered peer-to-peer financial system, has received 32 submissions and accepted 4 papers for inclusion in this book
• 8th Workshop on Trusted Smart Contracts (WTSC 2024), dealing with smart contracts and other decentralised applications, accepted 5 papers from 11 submissions; and the
• 5th Workshop on Coordination of Decentralized Finance (CoDecFin 2024), discussing multi-disciplinary issues regarding technologies and operations of decentralized finance based on permissionless blockchain, has accepted 8 full and 1 short paper from 15 submissions.