Structure-Preserving Chosen-Ciphertext Security With Shorter Verifiable Ciphertexts
(2017) 20th International Conference on Practice and Theory in Public-Key Cryptography - PKC 2017 — Location: Amsterdam (the Netherlands) (28.March.2017)
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- Abstract
- Structure-preserving cryptography is a world where messages, signatures, ciphertexts and public keys are entirely made of elements of a group over which a bilinear map is efficiently computable. While structure-preserving signatures have received much attention the last 6 years, structure-preserving encryption schemes have undergone slower development. In particular, the best known structure-preserving cryptosystems with chosen-ciphertext (IND-CCA2) security either rely on symmetric pairings or require long ciphertexts comprised of hundreds of group elements or do not provide publicly verifiable ciphertexts. We provide a publicly verifiable construction based on the SXDH assumption in asymmetric bilinear groups e : G׈ G→GT, which features relatively short ciphertexts. For typical parameters, our ciphertext size amounts to less than 40 elements of G. As a second contribution, we provide a structure-preserving encryption scheme with perfectly randomizable ciphertexts and replayable chosen-ciphertext security. Our new RCCA secure system significantly improves upon the best known system featuring similar properties in terms of ciphertext size.
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Citations
Libert, B., Peters, T., & Qian, C. (2017). Structure-Preserving Chosen-Ciphertext Security With Shorter Verifiable Ciphertexts. Proceedings of the 20th International Conference on Practice and Theory in Public-Key Cryptography - PKC 2017, LNCS(10174), 247-276. https://hdl.handle.net/2078.5/175667 (Original work published 2017)