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.
