Identity-based matchmaking encryption (IB-ME) is an advanced encryption scheme that allows both the sender and the receiver to specify their respective identities. We study the notion of hierarchical IB-ME (HIB-ME), which augments IB-ME with delegation capabilities. Specifically, we first formalize HIB-ME and construct it based on hierarchical identity-based encryption and hierarchical identity-based signature. Moreover, as applications of the HIB-ME, we show two chosen ciphertext secure (H)IB-ME constructions for different security levels.
Identity-based matchmaking encryption (IB-ME) is an advanced encryption scheme that allows both the sender and the receiver to specify their respective identities. We study the notion of hierarchical IB-ME (HIB-ME), which augments IB-ME with delegation capabilities. Specifically, we first formalize HIB-ME and construct it based on hierarchical identity-based encryption and hierarchical identity-based signature. Moreover, as applications of the HIB-ME, we show two chosen ciphertext secure (H)IB-ME constructions for different security levels.
Matchmaking encryption constructed in the identity-based encryption setting, named identity-based matchmaking encryption (IB-ME), requires both sender and receiver to specify target identity simultaneously for each other for message decryption. The IB-ME schemes can not only ensure the privacy of the sender and the message but also provide authentication for the data source. In order to resist quantum-attacks, we put forward a post-quantum secure IB-ME scheme. Compared with Ateniese et al.'s scheme and Francati et al.'s scheme, our approach eliminates the use of functional encryption, predicate encryption and signature scheme, and only uses a more simple preimage sampling function and an IBE scheme in the way of non-black-box. Compared with post-quantum secure IB-MEs proposed currently, our scheme is the first non-black-box construction based on standard lattice assumptions such as LWE and ISIS.
Abstract Identity‐based Matchmaking Encryption (IB‐ME) is an extension notion of matchmaking encryption (CRYPTO 2019), where a sender and a receiver can specify an access policy for the other party. In IB‐ME, data encryption is performed by not only a receiver identity but also a sender's encryption key. Nevertheless, previous IB‐ME schemes have not considered the problem of efficient revocation . Hence, the authors introduce a new notion of revocable IB‐ME (RIB‐ME) and formalise the syntax and security model of RIB‐ME. In particular, the authors give an effective and simple construction of RIB‐ME in the standard model, whose security is reduced to the hardness of decisional bilinear Diffie—Hellman problem and computational Diffie—Hellman problem. In addition, the authors show two extensions of our RIB‐ME scheme to consider chosen‐ciphertext security and forward privacy.
Scholars are currently exploring Identity-Based Matchmaking Encryption (IB-ME), which allows senders and receivers to specify identities for decryption, protecting sensitive data in ciphertexts. Our work advances Revocable Identity-Based Matchmaking Encryption (RIB-ME) by adding revocation of decryption rights from unauthorized users. However, most RIB-ME systems rely on the Diffie-Hellman assumption, making them vulnerable to quantum computing threats. Current security models also fail to fully capture adversaries' evolving capabilities, risking unexpected exploits. To address this, we propose a flexible RIB-ME framework, inspired by Wang et al., using a two-tier revocable hierarchical identity-based encryption (RHIBE) approach integrated with post-quantum cryptography. This creates the first quantum-resistant RIB-ME system. We also introduce a detailed security model defining adversaries' strengths and attack patterns over time, enhancing the system's robustness and reliability across various practical scenarios.
In recent years, scholars have developed Identity-Based Matching Encryption (IB-ME), which enables both the sender and the receiver to specify identities, ensuring ciphertext confidentiality only when these identities match. Building on this concept, our work introduces Revocable Identity-Based Matching Encryption (RIB-ME), which incorporates a revocable mechanism to withdraw decryption rights from unauthorized users. Current RIB-ME schemes rely on a variant of the Diffie-Hellman assumption, rendering it susceptible to quantum computing attacks. To address this vulnerability, we propose a generic construction of RIB-ME inspired by Wang et al. Our approach employs two-level Revocable Hierarchical Identity-Based Encryption (RHIBE) and Identity-Based Signature (IBS) and is compatible with post-quantum encryption schemes. This enables the development of a generic construction of RIB-ME and the creation of the first post-quantum RIB-ME through the use of post-quantum constructions.
Puncturable encryption (PE), introduced by Green and Miers at IEEE S$&$P 2015, allows recipients to update their decryption keys to revoke decryption capability for selected messages without communicating with senders. In general, it allows users to control which ciphertexts their keys may decrypt. The notion of PE has been found very useful in many applications, such as asynchronous messaging systems, group messaging systems, public-key watermarking schemes, secure cloud emails, and many more. In this paper, we introduce a new primitive called hierarchical identity-based puncturable encryption (HIBPE) that enhances the concept of PE by allowing more general key delegation and flexible key puncture. It enhances the capability of the data owner for multi-level encrypted data sharing within a group of users by delegating the decryption keys of the users in higher-levels to generate decryption keys for the users in lower-levels. Moreover, it allows users to puncture (update) their decryption keys on tags so that a decryption key punctured on a tag can no longer decrypt ciphertexts under this tag. In addition, to control access to the users' data, the higher-level users can further puncture the delegated keys (for lower-level users) with some tags such that the part of the owner's data is labeled by the punctured tags will no longer be accessible by the lower-level users. These features offer an efficient and flexible solution for encrypted data sharing as well as data-access control mechanisms in a hierarchical setting. We propose the formal definition and security model for HIBPE schemes and provide a concrete HIBPE scheme based on the hardness of the learning with errors problem in the standard model. Further, we provide a generic construction of forward secure hierarchical identity-based encryption (fs-HIBE) from HIBPE, which enables the first quantum-safe construction of fs-HIBE in the standard model. Moreover, this is the first fs-HIBE construction by exploring the concept of PE. The proposed fs-HIBE provides quantum-safe protection for secret keys from exposure in multi-level encrypted data sharing by evolving the keys with time.
Receiver selective opening (RSO) security considers the security of encryption schemes under the scenario of a single sender and multiple receivers, where an adversary is allowed to adaptively corrupt some receivers’ secret keys. RSO security has been proven to be more secure than indistinguishability-based security notions. A lot of research has focused on RSO security in terms of public-key encryption and identity-based encryption (IBE); however, hierarchical IBE (HIBE), which is a generalization of IBE, is still lacking in the study, and how to obtain such a construction remains an open problem. To address this gap, we initiate a study of RSO security on HIBE in this work. Precisely, we first formalize the definition of simulation-based RSO against identity-chosen-plaintext/ciphertext attacks in the k-challenge setting (SIM-ID-RSO k -CPA/CCA) for HIBE. We then present generic SIM-ID-RSO k -CCA secure HIBE constructions by introducing the double secret key paradigm. Specifically, we show that a SIM-ID-RSO k -CCA secure HIBE scheme can be obtained from an IND-ID-CPA secure HIBE scheme as well as a one-time signature scheme that satisfies strong unforgeability. Through our general construction, we can derive various concrete schemes based on different hard assumptions (e.g., lattice-based and pairing-based SIM-ID-RSO k -CCA secure HIBE schemes) according to usage requirements.