The book "Cryptographic Hardware and Embedded Systems -- CHES 2015" documents the refereed proceedings of the 17th International Workshop on Cryptographic Hardware and Embedded Systems, which took place in September 2015 in Saint Malo, France. This volume includes 34 full papers that were carefully selected from 128 submitted works. The contributions cover a wide range of topics relevant to professionals and researchers in the fields of cryptography and the security of embedded systems. The topics addressed range from processing techniques in side-channel analysis to cryptographic hardware implementations and homomorphic encryption in hardware. This collection provides valuable insights into current developments and challenges in cryptography and is an important resource for anyone involved in the security of hardware and embedded systems.