Wildcard identity-based encryption (WIBE) is a generalization of hierarchical identity-based encryption (HIBE) where a sender can simultaneously encrypt messages to a group of users matching a certain pattern, defined as a sequence of identities and wildcards. This special feature makes WIBE a promising solution to distributed IoT data security. In this paper, we propose the first construction of a post-quantum WIBE scheme. Our scheme is proven secure in the standard model, and it enjoys the security in the future quantum computer era.
Proxy re-encryption (PRE), introduced by Blaze, Bleumer, and Strauss at EUROCRYPT 98, offers delegation of decryption rights, i.e., it securely enables the re-encryption of ciphertexts from one key to another, without relying on trusted parties. PRE allows a semi-trusted third party termed as a “proxy” to securely divert ciphertexts of a user (delegator) to another user (delegatee) without revealing any information about the underlying messages to the proxy. Attribute-based proxy re-encryption (ABPRE) generalizes PRE by allowing such transformation of ciphertext under an access-policy into another ciphertext under a new access policy. Such a primitive facilitates fine-grained secure sharing of encrypted data in the cloud. In order to capture the application goals of PRE, the security model of (Attribute-based) PRE evolves over the decades. There are two well-established notions of security for (Attribute-based) proxy re-encryption schemes: security under chosen-plaintext attacks (C