A Chosen-Ciphertext Secure Fuzzy Identity-Based Proxy Re-Encryption Scheme

Green and Ateniese introduced the notion of identity-based proxy re-encryption (IB-PRE), whereby the proxy can covert a ciphertext encrypted under the delegator's identity to an encryption under the delegatee's identity of the same message. In some situations, biometric, such as dactylogram, was used as identities. However, these biometric identities will inherently have some noise when they are sampled each time. To make identity-based proxy re-encryption flexible on identities, we introduced a new primitive called fuzzy identity-based proxy re-encryption (FIB-PRE), in which an identity is viewed as a set of descriptive attributes. In a fuzzy identity-based proxy re-encryption scheme, an identity can decrypt a ciphertext re-encrypted under another identity, if and only if and are close to each other as measured by the "set overlap" distance metric. In this work, we first formulate the security model of a FIB-PRE scheme. Finally, we present a construction of FIB-PRE and prove its CCA security under the decisional bilinear Diffie-Hellman (DBDH) assumption in the random model.