Paper 2008/304

A New Randomness Extraction Paradigm for Hybrid Encryption

Eike Kiltz, Krzysztof Pietrzak, Martijn Stam, and Moti Yung


We present a new approach to the design of IND-CCA2 secure hybrid encryption schemes in the standard model. Our approach provides an efficient generic transformation from 1-universal to 2-universal hash proof systems. The transformation involves a randomness extractor based on a 4-wise independent hash function as the key derivation function. Our methodology can be instantiated with efficient schemes based on standard intractability assumptions such as DDH, QR and Paillier. Interestingly, our framework also allows to prove IND-CCA2 security of a hybrid version of 1991's Damgaard's ElGamal public-key encryption scheme under the DDH assumption.

Available format(s)
Public-key cryptography
Publication info
Published elsewhere. This is the full version of the paper in EUROCRYPT 2009
Chosen-ciphertext securityhybrid encryptionhash proof systemsElGamal
Contact author(s)
kiltz @ cwi nl
2009-07-22: last of 2 revisions
2008-07-08: received
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Creative Commons Attribution


      author = {Eike Kiltz and Krzysztof Pietrzak and Martijn Stam and Moti Yung},
      title = {A New Randomness Extraction Paradigm for Hybrid Encryption},
      howpublished = {Cryptology ePrint Archive, Paper 2008/304},
      year = {2008},
      note = {\url{}},
      url = {}
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