This book constitutes the refereed proceedings of the 11th International Conference on Information Systems Security, ICISS 2015, held in Kolkata, India, in December 2015.

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