Best Security Measures to Reduce Cyber-incident and Data Breach Risks -- Synthesizing Privacy-Preserving Location Traces Including Co-locations -- Quantitative Rubric for Privacy Policy Analysis -- Rethinking the Limits of Mobile Operating System Permissions -- Interdependent privacy issues are pervasive among third-party applications -- SPGC: An Integrated Framework of Secure Computation and Differential Privacy for Collaborative Learning -- A k-anonymised Federated Learning Framework with Decision Trees -- Anonymizing Machine Learning Models -- A New Privacy Enhancing Beacon Scheme in V2X Communication -- Next Generation Data Masking Engine -- Towards a Formal Approach for Data Minimization in Programs -- Virtual ASICs: Generalized Proof-of-Stake Mining in Cryptocurrencies -- Asymmetric Asynchronous Byzantine Consensus -- Using Degree Centrality to Identify Market Manipulation on Bitcoin -- Augmenting MetaMask to support TLS-endorsed Smart Contracts -- Smart Contracts for Incentivized Outsourcing of Computation -- Anonymous Sidechains -- Filling the Tax Gap via Programmable Money -- Impact of delay classes on the data structure in IOTA -- Secure Static Content Delivery for CDN using Blockchain Technology -- Lattice-Based Proof-of-Work for Post-Quantum Blockchains -- Blockchain-based Two-Factor Authentication for Credit Card Validation -- Homomorphic decryption in blockchains via compressed discrete-log lookup tables.

This book constitutes the refereed proceedings and revised selected papers from the 16th International Workshop on Data Privacy Management, DPM 2021, and the 5th International Workshop on Cryptocurrencies and Blockchain Technology, CBT 2021, which were held online on October 8, 2021, in conjunction with ESORICS 2021. The workshops were initially planned to take place in Darmstadt, Germany, and changed to an online event due to the COVID-19 pandemic. The DPM 2021 workshop received 25 submissions and accepted 7 full and 3 short papers for publication. These papers were organized in topical sections as follows: Risks and privacy preservation; policies and regulation; privacy and learning. For CBT 2021 6 full papers and 6 short papers were accepted out of 31 submissions. They were organized in topical sections as follows: Mining, consensus and market manipulation; smart contracts and anonymity.