Timed-Release Cryptography: New Constructions and Assumptions
Juan Garay
Bell Labs - Lucent Technologies
Monday, September 29, 2:00PM
Lieb 3rd floor Conference Room
Computer Science Department
Stevens Institute of Technology
Abstract
The goal of timed-release crypto is to "send information into the
future," i.e., to apply a cryptographic transformation (e.g.,
encryption, signature) to a message so that it cannot be retrieved or
verified by anyone until a pre-determined amount of time has passed.
Although this problem was formulated in the early nineties,
constructions that are efficient and at the same time satisfy strong
verifiability properties (such as right content of the encrypted
message, or amount of time that will be needed to open it) are
relatively recent. In this talk we present two of such efficient
constructions that allow for the timed release of information and
timed fair exchange; the former has applications to standard digital
signatures that can only be universally verified in the future, while
the latter has applications to contract signing and multi-party
computation problems, such as the "socialist millionaires problem."
These constructions rely on some new/generalized complexity
assumptions, which we also discuss.