Cryptanalysis of Multivariate Systems -- Properties of the Discrete Differential with Cryptographic Applications -- Growth of the Ideal Generated by a Quadratic Boolean Function -- Mutant Zhuang-Zi Algorithm -- Cryptanalysis of Two Quartic Encryption Schemes and One Improved MFE Scheme -- Cryptanalysis of Code-Based Systems -- Cryptanalysis of the Niederreiter Public Key Scheme Based on GRS Subcodes -- Grover vs. McEliece -- Information-Set Decoding for Linear Codes over F q -- A Timing Attack against the Secret Permutation in the McEliece PKC -- Practical Power Analysis Attacks on Software Implementations of McEliece -- Design of Encryption Schemes -- Key Exchange and Encryption Schemes Based on Non-commutative Skew Polynomials -- Designing a Rank Metric Based McEliece Cryptosystem -- Secure Variants of the Square Encryption Scheme -- Low-Reiter: Niederreiter Encryption Scheme for Embedded Microcontrollers -- Design of Signature Schemes -- Strongly Unforgeable Signatures and Hierarchical Identity-Based Signatures from Lattices without Random Oracles -- Proposal of a Signature Scheme Based on STS Trapdoor -- Selecting Parameters for the Rainbow Signature Scheme.

This book constitutes the refereed proceedings of the Third International Workshop on Post-Quantum Cryptography, PQCrypto 2010, held in Darmstadt, Germany, in May 2010. The 16 revised full papers presented were carefully reviewed and selected from 32 submissions. The papers are organized in topical sections on cryptanalysis of multivariate systems, cryptanalysis of code-based systems, design of encryption schemes, and design of signature schemes.