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Chosen-ciphertext security from identity-based encryption. (English) Zbl 1122.94358
Cachin, Christian (ed.) et al., Advances in cryptology – EUROCRYPT 2004. International conference on the theory and applications of cryptographic techniques, Interlaken, Switzerland, May 2–6, 2004. Proceedings. Berlin: Springer (ISBN 3-540-21935-8/pbk). Lecture Notes in Computer Science 3027, 207-222 (2004).
Summary: We propose a simple and efficient construction of a CCA-secure public-key encryption scheme from any CPA-secure identity-based encryption (IBE) scheme. Our construction requires the underlying IBE scheme to satisfy only a relatively “weak” notion of security which is known to be achievable without random oracles; thus, our results provide a new approach for constructing CCA-secure encryption schemes in the standard model. Our approach is quite different from existing ones; in particular, it avoids non-interactive proofs of “well-formedness” which were shown to underlie most previous constructions. Furthermore, applying our conversion to some recently-proposed IBE schemes results in CCA-secure schemes whose efficiency makes them quite practical.
Our technique extends to give a simple and reasonably efficient method for securing any binary tree encryption (BTE) scheme against adaptive chosen-ciphertext attacks. This, in turn, yields more efficient CCA-secure hierarchical identity-based and forward-secure encryption schemes in the standard model.
For the entire collection see [Zbl 1051.94003].

94A60 Cryptography
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