Paper 2007/036
Chosen-Ciphertext Secure Key-Encapsulation Based on Gap Hashed Diffie-Hellman
Eike Kiltz
Abstract
We propose a practical key encapsulation mechanism with a simple and intuitive design concept. Security against chosen-ciphertext attacks can be proved in the standard model under a new assumption, the Gap Hashed Diffie-Hellman (GHDH) assumption. The security reduction is tight and simple. Secure key encapsulation, combined with an appropriately secure symmetric encryption scheme, yields a hybrid public-key encryption scheme which is secure against chosen-ciphertext attacks. The implied encryption scheme is very efficient: compared to the previously most efficient scheme by Kurosawa and Desmedt [Crypto 2004] it has 128 bits shorter ciphertexts, between 25-50% shorter public/secret keys, and it is slightly more efficient in terms of encryption/decryption speed. Furthermore, our scheme enjoys (the option of) public verifiability of the ciphertexts and it inherits all practical advantages of secure hybrid encryption.
Metadata
- Available format(s)
-
PDF
- Category
- Public-key cryptography
- Publication info
- Published elsewhere. Preliminary version in PKC 2007. This is the full version.
- Keywords
- Chosen-ciphertext securityPublic-key encryptionkey encapsulation
- Contact author(s)
- kiltz @ cwi nl
- History
- 2007-02-14: revised
- 2007-02-14: received
- See all versions
- Short URL
- https://ia.cr/2007/036
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2007/036,
author = {Eike Kiltz},
title = {Chosen-Ciphertext Secure Key-Encapsulation Based on Gap Hashed Diffie-Hellman},
howpublished = {Cryptology {ePrint} Archive, Paper 2007/036},
year = {2007},
url = {https://eprint.iacr.org/2007/036}
}
