This book constitutes the thoroughly refereed post-conference proceedings of the 21st International Conference on Financial Cryptography and Data Security, FC 2017, held in Sliema, Malta, in April 2017.The 30 revised full papers and 5 short papers were carefully selected and reviewed from 132 submissions. The papers are grouped in the following topical sections: Privacy and Identity Management Privacy and Data Processing Cryptographic Primitives and API's Vulnerabilities and Exploits Blockchain Technology Security of Internet Protocols Blind signatures Searching and Processing Private Data Secure Channel Protocols and Privacy in Data Storage and Retrieval.

Datenverarbeitung / Anwendungen / Betrieb, Verwaltung Datenverarbeitung / Datenverschlüsselung, Kryptografie EDV / Theorie / Sicherheit E-Business Electronic Commerce - E-Commerce E-Venture Internet / Electronic Commerce Net Economy Netzwerk (elektronisch) Computingtechnologypolicy FinancialTechnology Internet NetworkSecurity Privacy Softwareengineering SystemsSecurity WorldWideWeb authentication computercrime cryptography databasesecurity electronicdocumentidentificationsystems encryption formalmethodsandtheoryofsecurity humanandsocietalaspectsofsecurityandprivacy intrusion/anomalydetectionandmalwaremitigation publickeycryptography securityinhardware softwareandapplicationsecurity