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Secure Hybrid Encryption from Weakened Key Encapsulation (2007)
| Citations: | 55 - 9 self |
BibTeX
@MISC{Hofheinz07securehybrid,
author = {Dennis Hofheinz and Eike Kiltz},
title = { Secure Hybrid Encryption from Weakened Key Encapsulation},
year = {2007}
}
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Abstract
We put forward a new paradigm for building hybrid encryption schemes from constrained chosen-ciphertext secure (CCCA) key-encapsulation mechanisms (KEMs) plus authenticated symmetric encryption. Constrained chosen-ciphertext security is a new security notion for KEMs that we propose. CCCA has less demanding security requirements than standard chosen-ciphertext (CCA) security (since it requires the adversary to have a certain plaintext-knowledge when making a decapsulation query) yet we can prove that CCCA is sufficient for secure hybrid encryption. Our notion is not only useful to express the Kurosawa-Desmedt public-key encryption scheme and its generalizations to hash-proof systems in an abstract KEM/DEM security framework. It also has a very constructive appeal, which we demonstrate with a new encryption scheme whose security relies on a class of intractability assumptions that we show (in the generic group model) strictly weaker than the Decision Diffie-Hellman (DDH) assumption. This appears to be the first practical public-key encryption scheme in the literature from an algebraic assumption strictly weaker than DDH.
Keyphrases
secure hybrid encryption key encapsulation chosen-ciphertext security security requirement hash-proof system hybrid encryption scheme constructive appeal kurosawa-desmedt public-key encryption scheme first practical public-key encryption scheme intractability assumption hybrid encryption generic group model weak security assumption new security notion new paradigm decision diffie-hellman new encryption scheme algebraic assumption decapsulation query key-encapsulation mechanism authenticated symmetric encryption certain plaintextknowledge abstract kem dem security framework chosen-ciphertext secure
