## CryptoDB

### Andris Ambainis

#### Publications

Year
Venue
Title
2019
CRYPTO
We present an improved version of the one-way to hiding (O2H) Theorem by Unruh, J ACM 2015. Our new O2H Theorem gives higher flexibility (arbitrary joint distributions of oracles and inputs, multiple reprogrammed points) as well as tighter bounds (removing square-root factors, taking parallelism into account). The improved O2H Theorem makes use of a new variant of quantum oracles, semi-classical oracles, where queries are partially measured. The new O2H Theorem allows us to get better security bounds in several public-key encryption schemes.
2014
EPRINT
2004
PKC
2003
EPRINT
We develop cryptographically secure techniques to guarantee unconditional privacy for respondents to polls. Our constructions are efficient and practical, and are shown not to allow cheating respondents to affect the tally'' by more than their own vote --- which will be given the exact same weight as that of other respondents. We demonstrate solutions to this problem based on both traditional cryptographic techniques and quantum cryptography.
1996
EPRINT
Private information retrieval was introduced by Chor, Goldreich, Kushilevitz and Sudan. It is the problem of reading a bit from the database so that it remains secret which bit we need. If the database exists in several identical copies, it is possible to ask queries so that each of copies alone does not get any information about the adress of the needed bit. We construct a scheme for private information retrieval with k databases and O(n sup (1/(2k-1)) ) bits of communication.

#### Coauthors

Mike Hamburg (1)
Markus Jakobsson (2)
Helger Lipmaa (2)
Ansis Rosmanis (1)
Dominique Unruh (2)