Proxy Re-encryption with Keyword Search from Anonymous Conditional Proxy Re-encryption

Proxy re-encryption (PRE) allows a proxy to transform a cipher text for Alice (delegator) to be the one which can be decrypted by Bob (delegatee). Since it is introduced by Blaze et al. in 1998, many variants of PRE have been proposed. In this paper, we concentrate on two of them: anonymous conditional proxy re-encryption (ACPRE) and constrained proxy re-encryption with keyword search (PRES). Conditional proxy re-encryption (CPRE) is a primitive which only allows those cipher texts satisfying the condition can be re-encrypted correctly by the proxy. Anonymous conditional proxy re-encryption (ACPRE) requires the proxy not knowing which condition the cipher text associated with. PRES is a primitive which allows the proxy simultaneously re-encrypt and search the delegator's cipher text. Based on the PRES proposed by Shao et al., We show the definition of constrained proxy re-encryption with keyword search (CPRES), give its security models and discuss its potential applications. At last, based on a concrete ACPRE scheme, we construct a concrete CPRES scheme.