This book constitutes the refereed proceedings of the Second International Workshop on Coding and Cryptology, IWCC 2009, held in Zhangjiajie, China, in June 2009.

An Infinite Class of Balanced Vectorial Boolean Functions with Optimum Algebraic Immunity and Good Nonlinearity.- Separation and Witnesses.- Binary Covering Arrays and Existentially Closed Graphs.- A Class of Three-Weight and Four-Weight Codes.- Equal-Weight Fingerprinting Codes.- Problems on Two-Dimensional Synchronization Patterns.- A New Client-to-Client Password-Authenticated Key Agreement Protocol.- Elliptic Twin Prime Conjecture.- Hunting for Curves with Many Points.- List Decoding of Binary Codes-A Brief Survey of Some Recent Results.- Recent Developments in Low-Density Parity-Check Codes.- On the Applicability of Combinatorial Designs to Key Predistribution for Wireless Sensor Networks.- On Weierstrass Semigroups of Some Triples on Norm-Trace Curves.- ERINDALE: A Polynomial Based Hashing Algorithm.- A Survey of Algebraic Unitary Codes.- New Family of Non-Cartesian Perfect Authentication Codes.- On the Impossibility of Strong Encryption Over .- Minimum Distance between Bent and Resilient Boolean Functions.- Unconditionally Secure Approximate Message Authentication.- Multiplexing Realizations of the Decimation-Hadamard Transform of Two-Level Autocorrelation Sequences.- On Cayley Graphs, Surface Codes, and the Limits of Homological Coding for Quantum Error Correction.