Multi-identity single-key decryption without random oracles



Publication Details

Guo, F., Mu, Y., Chen, Z. & Xu, L. (2007). Multi-identity single-key decryption without random oracles. In D. Pei & M. Yung (Eds.), International Conference on Information Security and Cryptology (pp. 384-398). Germany: Springer-Verlag.


Multi-Identity Single-Key Decryption (MISKD) is an Identity-Based Encryption (IBE) system where a private decryption key can map multiple public keys (identities). More exactly, in MISKD, a single private key can be used to decrypt multiple ciphertexts encrypted with different public keys associated to the private key. MISKD is a variant of IBE and offers convenience to users who have to manage many private keys in a standard IBE. The notion of MISKD was recently introduced by Guo, Mu and Chen in Pairing 2007. They proposed a concrete MISKD scheme and proved its security based on the Bilinear Strong Diffie-Hellman problem (q-BSDH) in random oracle model. In this paper, we present a novel MISKD scheme that is provably secure in the selective-ID model based on the Decisional Bilinear Diffie-Hellman (DBDH) assumption. Our scheme is more efficient in decryption.

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