Chosen Ciphertext Secure Keyed-Homomorphic Public-Key Encryption

  • Keita Emura
  • Goichiro Hanaoka
  • Go Ohtake
  • Takahiro Matsuda
  • Shota Yamada
Conference paper

DOI: 10.1007/978-3-642-36362-7_3

Part of the Lecture Notes in Computer Science book series (LNCS, volume 7778)
Cite this paper as:
Emura K., Hanaoka G., Ohtake G., Matsuda T., Yamada S. (2013) Chosen Ciphertext Secure Keyed-Homomorphic Public-Key Encryption. In: Kurosawa K., Hanaoka G. (eds) Public-Key Cryptography – PKC 2013. Lecture Notes in Computer Science, vol 7778. Springer, Berlin, Heidelberg

Abstract

In homomorphic encryption schemes, anyone can perform homomorphic operations, and therefore, it is difficult to manage when, where and by whom they are performed. In addition, the property that anyone can ‘‘freely” perform the operation inevitably means that ciphertexts are malleable, and it is well-known that adaptive chosen ciphertext (CCA) security and the homomorphic property can never be achieved simultaneously. In this paper, we show that CCA security and the homomorphic property can be simultaneously handled in situations that the user(s) who can perform homomorphic operations on encrypted data should be controlled/limited, and propose a new concept of homomorphic public-key encryption, which we call keyed-homomorphic public-key encryption (KH-PKE). By introducing a secret key for homomorphic operations, we can control who is allowed to perform the homomorphic operation. To construct KH-PKE schemes, we introduce a new concept, a homomorphic transitional universal hash family, and present a number of KH-PKE schemes through hash proof systems. We also present a practical construction of KH-PKE from the DDH assumption. For ℓ-bit security, our DDH-based scheme yields only ℓ-bit longer ciphertext size than that of the Cramer-Shoup PKE scheme.

Keywords

homomorphic public key encryption CCA2 security hash proof system 

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Copyright information

© International Association for Cryptologic Research 2013

Authors and Affiliations

  • Keita Emura
    • 1
  • Goichiro Hanaoka
    • 2
  • Go Ohtake
    • 3
  • Takahiro Matsuda
    • 2
  • Shota Yamada
    • 4
  1. 1.National Institute of Information and Communications Technology (NICT)Japan
  2. 2.Japan Broadcasting CorporationJapan
  3. 3.National Institute of Advanced Industrial Science and Technology (AIST)Japan
  4. 4.The University of TokyoJapan

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