The recent development of quantum computing and quantum algorithmics has raised important questions in cryptography. With Shor s algorithm (Peter W. Shor, Polynomial-TimeAlgorithms for Prime Factorization and Discrete Lo- rithmsonaQuantumComputer ,SIAMJ.Sci.Statist.Comput.41(2):303-332, 1999)thecollapseofsomeofthemostwidelyusedtechniquesfor securingdigital communications has become a possibility. In consequence, the everlasting duty of the cryptographic research community to keep an eye on alternative te- niques has become an urgent necessity. Post-quantum cryptography was born. Its primary concern is the study of public-key cryptosystems that remain - cure in a world with quantum computers. Currently, four families of public-key cryptosystemsseemto havethis potential:code-based,hash-based,lattice-based and multivariate public-key cryptosystems. Other techniques may certainly join this rapidly growing research area. With the PQCrypto conference series, this emerging community has created a place to disseminate results, exchange new ideas and de?ne the state of the art. In May of 2006, the First International Workshop on Post-Quantum Cryptography was held at the Katholieke Univ- siteit Leuvenin Belgium with support fromthe EuropeanNetworkof Excellence ECRYPT.TheSecondInternationalWorkshoponPost-QuantumCryptography, PQCrypto2008,washeldattheUniversityofCincinnati,USA, inOctober2008.

Inhalt
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.