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.
