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Private Branching Programs: On Communication-Efficient Cryptocomputing

Speaker: Helger Lipmaa University College London
Time: 2008-05-21 13:30-2008-05-21 14:30
Venue: FIT Building 4-603, Tsinghua University
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We polish a recent cryptocomputing method that makes it possible to cryptocompute every language in $\mathbf{L/poly}$. We give several nontrivial applications, including: (a) A CPIR protocol with log-squared communication and sublinear server-computation by giving a secure function evaluation protocol for Boolean functions with similar performance, (b) A protocol that makes it possible to compute (say) how similar is client's input to an element in server's database, without revealing any information to the server, (c) A protocol for private database updating with low amortized complexity.

Short Bio:

Helger Lipmaa is from Estonia. He was constantly one of the best in Estonian mathematics and informatics olympiads during the high school. In 1998 and 1999 he got an award from the Estonian Science Foundation, Commission for Exact Sciences, for successful research (only awarded to a single researcher a year). He got his PhD from University of Tartu in 1999. From 2001 to early 2005 he was a professor of cryptology at the Helsinki University of Technology. Since 2006, he is working at the University College London.        He is best known for his work on efficient and secure time-stamping, secure electronic auctions, privacy-preserving data mining. Moreover, he has written world's fastest implementations of AES (which were available commercially) and several other block ciphers for the Pentium. He also keeps up the world-famous list of cryptopointers at http://www.adastral.ucl.ac.uk/~helger/crypto . He has been awarded about 10 grants in 1994--2006, he has been a member of a PC of 30 conferences in 2002--2008, and he is on the steering committee of NordSec. He has consulted Estonian government on e-voting and digital signatures (Estonia is the first country to have nationwide e-voting).