A Unified Methodology For Constructing Public-Key Encryption Schemes Secure Against Adaptive Chosen-Ciphertext Attack

Edith Elkind; Amit Sahai

Paper 2002/042

A Unified Methodology For Constructing Public-Key Encryption Schemes Secure Against Adaptive Chosen-Ciphertext Attack

Edith Elkind and Amit Sahai

Abstract

We introduce a new methodology for achieving security against adaptive chosen-ciphertext attack (CCA) for public-key encryption schemes, which we call the {\em oblivious decryptors model}. The oblivious decryptors model generalizes both the two-key model of Naor and Yung, as well the Cramer--Shoup encryption schemes. The key ingredient in our new paradigm is Sahai's notion of Simulation-Sound NIZK proofs. Our methodology is easy to use: First, construct an encryption scheme which satisfies the ``bare'' oblivious-decryptors model: This can be done quite easily, with simple proofs of security. Then, by adding a Simulation-Sound NIZK proof, the scheme becomes provably CCA-secure. Note that this paradigm allows for the use of {\em efficient} special-purpose Simulation-Sound NIZK proofs, such as those recently put forward by Cramer and Shoup. We also show how to present all known efficient (provably secure) CCA-secure public-key encryption schemes as special cases of our model.

Note: Fixed some typos.

Metadata

Available format(s): PS
Category: Public-key cryptography
Publication info: Published elsewhere. Unknown where it was published
Keywords: chosen-ciphertext security
Contact author(s): elkind @ cs princeton edu
History: 2002-04-05: last of 2 revisions; 2002-04-05: received; See all versions
Short URL: https://ia.cr/2002/042
License: CC BY

BibTeX

@misc{cryptoeprint:2002/042,
      author = {Edith Elkind and Amit Sahai},
      title = {A Unified Methodology For Constructing Public-Key Encryption Schemes Secure Against Adaptive Chosen-Ciphertext Attack},
      howpublished = {Cryptology {ePrint} Archive, Paper 2002/042},
      year = {2002},
      url = {https://eprint.iacr.org/2002/042}
}