Encrypted Secret Sharing and Analysis by Plaintext Randomization

Stephen R.  Tate; Roopa Vishwanathan; Scott Weeks

Paper 2013/264

Encrypted Secret Sharing and Analysis by Plaintext Randomization

Stephen R. Tate, Roopa Vishwanathan, and Scott Weeks

Abstract

In this paper we consider the problem of secret sharing where shares are encrypted using a public-key encryption (PKE) scheme and ciphertexts are publicly available. While intuition tells us that the secret should be protected if the PKE is secure against chosen-ciphertext attacks (i.e., CCA-secure), formally proving this reveals some subtle and non-trivial challenges. We isolate the problems that this raises, and devise a new analysis technique called ``plaintext randomization'' that can successfully overcome these challenges, resulting in the desired proof. The encryption of different shares can use one key or multiple keys, with natural applications in both scenarios.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Published elsewhere. Minor revision. To appear in ISC 2013
Keywords: public-key cryptography secret sharing reduction cryptographic games
Contact author(s): vishwanathan roopa @ gmail com
History: 2013-10-23: revised; 2013-05-13: received; See all versions
Short URL: https://ia.cr/2013/264
License: CC BY

BibTeX

@misc{cryptoeprint:2013/264,
      author = {Stephen R.  Tate and Roopa Vishwanathan and Scott Weeks},
      title = {Encrypted Secret Sharing and Analysis by Plaintext Randomization},
      howpublished = {Cryptology {ePrint} Archive, Paper 2013/264},
      year = {2013},
      url = {https://eprint.iacr.org/2013/264}
}