Paper 2002/161 Original: eprint.iacr.org/2002/161 ↗

Practical Verifiable Encryption and Decryption of Discrete Logarithms

Jan Camenisch
Victor Shoup
Abstract

This paper presents a variant of the new public key encryption of Cramer and Shoup based on Paillier's decision composite residuosity assumption, along with an efficient protocol for verifiable encryption of discrete logarithms. This is the first verifiable encryption system that provides chosen ciphertext security and avoids inefficient cut-and-choose proofs. This has numerous applications, including fair exchange and key escrow. We also present efficient protocols for verifiable decryption, which has applications to, e.g., confirmer signatures. The latter protocols build on a new protocol for proving whether or not two discrete logarithms are equal that is of independent interest. Prior such protocols were either inefficient or not zero-knowledge.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
History
2003-08-25: last updated
2002-11-01: published
Short URL
https://ia.cr/2002/161
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2002/161,
      author = {Jan Camenisch and Victor Shoup},
      title = {Practical  Verifiable Encryption and Decryption of Discrete Logarithms},
      howpublished = {Cryptology {ePrint} Archive, Paper 2002/161},
      year = {2002},
      url = {https://eprint.iacr.org/2002/161}
}
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