This book constitutes the proceedings of the 11th International Conference on Security and Cryptography for Networks, SCN 2018, held in Amalfi, Italy, in September 2018. The 30 papers presented in this volume were carefully reviewed and selected from 66 submissions. They are organized in topical sections on signatures and watermarking; composability; encryption; multiparty computation; anonymity and zero knowledge; secret sharing and oblivious transfer; lattices and post quantum cryptography; obfuscation; two-party computation; and protocols.