This bookconstitutes the refereed proceedings of the 11th International Conference onInformation Systems Security, ICISS 2015, held in Kolkata, India, in December2015.

The 24revised full papers and 8 short papers presented together with 4 invited paperswere carefully reviewed and selected from 133 submissions. The papers addressthe following topics: access control; attacks and mitigation; cloud security;crypto systems and protocols; information flow control; sensor networks andcognitive radio; and watermarking and steganography.