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Is it true that the access policy only use "0" bit string? If yes, it is safe enough to encrypt the message with 2 attributes *0** and **0* (i.e., 1*** and ***1 are not needed)? First off, a numerical attribute such as *0** is nothing more than the ASCII string "*0**" which is then hashed. The following is a user's secret key: $$\text{SK}=\left(D=g^{\...


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Identity-based encryption (IBE) uses the receiver's identity as a public key. The sender specifies an identity that the receiver with a matching identity already has. An IBE scheme is anonymous if a ciphertext does not reveal the identity of the recipient. "Hierarchical IBE (HIBE) is a generalization of IBE that mirrors an organizational hierarchy. An ...


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At first, your syntax (Setup,GenKey,Encrypt,Query) seems to be the syntax of public-key encryption with keyword-search (PKES). In the case of predicate-based encryption, we use Decrypt rather than Query. The Sahai-Waters Fuzzy IBE I recommend Sahai and Waters: Fuzzy identity-based encryption (EUROCRYPT 2005) as a first step. I assume you know the basic of ...


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The previous answers skip an important fact. I think that a PE for all circuits and A FE for all circuits are equivalent in the sense that you can build the second from the first one (the opposite direction is trivial). A key for a circuit C with output size of $n$ bits can be implemented as $n$ PE keys in which the $i$-th key is relative to the circuit ...


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