Chosen-Ciphertext Security from Slightly Lossy Trapdoor Functions

10 years 6 months ago
Chosen-Ciphertext Security from Slightly Lossy Trapdoor Functions
Lossy Trapdoor Functions (LTDFs), introduced by Peikert and Waters (STOC 2008) have been useful for building many cryptographic primitives. In particular, by using an LTDF that loses a (1 − 1/ω(log n)) fraction of all its input bits, it is possible to achieve CCA security using the LTDF as a black-box. Unfortunately, not all candidate LTDFs achieve such a high level of lossiness. In this paper we drastically improve upon previous results and show that an LTDF that loses only a non-negligible fraction of a single bit can be used in a black-box way to build numerous cryptographic primitives, including oneway injective trapdoor functions, CPA secure public-key encryption (PKE), and CCA-secure PKE. We then describe a novel technique for constructing such slightly-lossy LTDFs and give a construction based on modular squaring.
Petros Mol, Scott Yilek
Added 14 Aug 2010
Updated 14 Aug 2010
Type Conference
Year 2010
Where PKC
Authors Petros Mol, Scott Yilek
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