Hierarchical Identity-based Encryption Research Articles

Tightly secure (H)IBE in the random oracle model

We present an adaptively secure identity-based encryption (IBE) scheme with constant sized parameters and constant security loss in multi-instance multi-ciphertext (MIMC) setting in prime-order groups, in the random oracle model. We then further construct an adaptively secure hierarchical identity-based encryption (HIBE) scheme with shorter sized parameters and constant security loss in the MIMC setting in prime-order groups, in the random oracle model.At the core of our technique, we observe that the pseudorandomness property of the random oracle matches the conditions of Left Subgroup Indistinguishability (LS) and Right Subgroup Indistinguishability (RS) in dual system groups (DSG) well, so that we can transform the queried secret keys and the challenge ciphertexts for once. We construct our IBE scheme from Agrawal and Chase's work (CCS 2017) and construct our HIBE scheme from Boneh et al.'s work (Eurocrypt 2005). As a byproduct of our IBE scheme, we construct a new DSG instantiation from Chen et al.'s work (Eurocrypt 2015) under bi-MDDH assumption.

IHIBE: A Hierarchical and Delegated Access Control Mechanism for IoT Environments

Ensuring authorized access control in the IoT is vital for privacy and safety protection. Our study presents the novel IHIBE framework, which combines IOTA (a distributed ledger technology) with hierarchical identity-based encryption (HIBE), thereby enhancing both IoT security and scalability. This approach secures access tokens and policies while reducing the computational demand on data owners. Our empirical findings reveal a significant performance gap, with access rights delegation on the Raspberry Pi 4 exceeding those on AWS by over 250%. Moreover, our analysis uncovers optimal identity policy depths: up to 640 identities on AWS and 640 on the Raspberry Pi 4 for systems with higher tolerable delays, and 320 identities on AWS versus 160 on the Raspberry Pi 4 for systems with lower tolerable delays. The system shows practical viability, exhibiting insignificant operational time differences compared to Zhang et al.’s schemes, particularly in access rights verification processes, with a minimal difference of 33.35%. Our extensive security assessment, encompassing scenarios like encrypted token theft and compromise of authority, affirms the efficacy of our challenge-response and last-word challenge (LWC) mechanisms. This study underscores the importance of platform choice in IoT system architectures and provides insights for deploying efficient, secure, and scalable IoT environments.

Anonymous hierarchical identity-based encryption with delegated traceability for cloud-based data sharing systems

Cloud-based data sharing systems (DSS) have become prevalent due to their ample storage and convenient access control. To protect sensitive data privacy in DSS, anonymous identity-based encryption (IBE) is a promising approach, enabling encryption using a recipient’s identity as a public key, while preventing identity and data leaks out of ciphertexts. As complete anonymity risks abuse and illegal usage, Blazy et al. introduced the notion called anonymous IBE with traceable identities (AIBET) at ARES’19, allowing users with tracing keys to identify recipients from ciphertexts. Unfortunately, existing AIBET schemes lack tracing key delegation and only consider security in weaker models (i.e., selective-identity attacks and chosen-plaintext attacks), posing risks of inconvenience and user privacy leaks. In this paper, we introduce a novel notion called anonymous hierarchical identity-based encryption with delegated traceability (AHIBEDT) for DSS. We formalize its syntax and define security notions in stronger models (i.e., adaptive-identity attacks and chosen-ciphertext attacks). In addition, we demonstrate that a concrete AHIBEDT scheme can be simply obtained from a hierarchical IBE scheme and a one-time signature scheme. The comparison results indicate that, despite a substantial increase in communication and computational costs, our approach achieves better security and functionality.

English

This paper proposes a solution to enhance the key management of Wireless Sensor Networks (WSNs) by integrating blockchain technology with Hierarchical Identity-Based Encryption. The aim is to establish a highly secure WSN structure. The current wireless network is improved by incorporating blockchain technology to increase security and reliability. However, the security of key management in dynamic WSNs is threatened by the vulnerability of untrusted Head Nodes(HN) to attack. The presence of an untrusted HN imposes a heavy burden on the sensors for key management, in addition to the already existing challenges. In order to overcome these issues, blockchain technology has been used to propose a secure key management scheme (BSKM). We offer a secure node movement technique and a safe cluster-building mechanism, with the blockchain acting as a trust machine to replace the major functions of the Head node. We run extensive simulations for security analyses. The findings show that the BSKM scheme is efficient and effective and is more suitable for enhancing the reliability of dynamic WSNs.

An Efficient Data Protection Scheme Based on Hierarchical ID-Based Encryption for MQTT

As Internet of Things (IoT) thrives over the whole world, more and more IoT devices and IoT-based protocols have been designed and proposed in order to meet people’s needs. Among those protocols, message queueing telemetry transport (MQTT) is one of the most emerging and promising protocols, which provides many-to-many message transmissions based on the “publish/subscribe” mechanism. It has been widely used in industries such as the energy industry, chemical engineering, self-driving, and so on. While transporting important messages, MQTT specification recommends the use of TLS protocol. However, the computation cost of TLS is too heavy. Since topics in a broker are stored with a hierarchical structure, in this manuscript, we propose a novel data protection protocol for MQTT from hierarchical ID-based encryption. Our protocol adopts the intrinsic hierarchical structures of MQTT, and achieves constant-size keys, i.e., independent of the depth in hierarchical structures. Besides, the formal security model for the proposed protocol have been defined in the manuscript. The proposed protocol have been formally proven chosen-plaintext secure under the ℓ-wBDHI assumption.

Blockchain-Based Data Sharing With Key Update for Future Networks

Future networks incorporate artificial intelligence to enable smart resource management and adaptive service provisioning. With a heterogeneous architecture and a large number of users in future networks, transparent and decentralized data sharing is required to promote data circulation and break data silos, for which blockchain is a potential solution to allow intelligent access permission control. However, it remains a challenging task to achieve flexible authorization management for blockchain-based data sharing and efficient key update for multi-users in case of key exposure. In this paper, we propose an intelligent blockchain-based data-sharing scheme with key update for future networks. First, we design a new encryption scheme, where keywords of data are extracted using machine learning algorithms that are published on the blockchain. Then, keywords of data and time validity are used to encrypt different types of data for flexible data authorization. Second, using hierarchical identity-based encryption, we construct an efficient key update mechanism, where update tokens are generated by invoking a smart contract deployed on the blockchain to facilitate key and ciphertext updates. We formally prove that the proposed scheme can guarantee three essential security properties: forward security, post-compromise security, and collusion attack resistance. On-chain and off-chain experiment results are provided to demonstrate that the proposed scheme can achieve computational and communication efficiency for key and ciphertext updates.

Quantum-safe Anonymous Hierarchical Identity-Based Encryption with Traceable Identities

Anonymous Identity Based Encryption (AIBET) scheme allows a tracer to use the tracing key to reveal the recipient’s identity from the ciphertext while keeping other data anonymous. This special feature makes AIBET a promising solution to distributed IoT data security since it can preserve both the privacy and the anonymity of a communication network but still give the server the ability to revoke the anonymity of some specific users in necessary situations (such as when their illegal behavior are detected). In this paper, we construct an efficient quantum-safe Hierarchical Identity-Based cryptosystem with Traceable Identities (AHIBET) with fully anonymous ciphertexts. We prove the security of our AHIBET scheme under the Learning with Errors (LWE) problem in the standard model.

ACR-MLM: a privacy-preserving framework for anonymous and confidential rewarding in blockchain-based multi-level marketing

Network marketing is a trading technique that provides companies with the opportunity to increase sales. With the increasing number of Internet-based purchases, several threats are increasingly observed in this field, such as user privacy violations, company owner (CO) fraud, the changing of sold products’ information, and the scalability of selling networks. This study presents the concept of a blockchain-based market called ACR-MLM that functions based on the multi-level marketing (MLM) model, through which registered users receive anonymous and confidential rewards for their own and their subgroups’ sales. Applying a public blockchain as the ACR-MLM framework’s infrastructure solves existing problems in MLM-based markets, such as CO fraud (against the government or its users), user privacy violations (obtaining their real names or subgroup users), and scalability (when vast numbers of users have been registered). To provide confidentiality and scalability to the ACR-MLM framework, hierarchical identity-based encryption (HIBE) was applied with a functional encryption (FE) scheme. Finally, the security of ACR-MLM is analyzed using the random oracle (RO) model and then evaluated.

A direct construction of continuous leakage-resilient (H)IBE scheme with CCA security from dual system encryption

Continuous leakage resilient semantically secure Identity-based Encryption (IBE) schemes created with dual system encryption technique were presented by Lewko et al. at TCC 2011 and Yuen et al. at Eurocrypt 2012, respectively. It has been a research challenge to achieve the security against chosen-ciphertext attacks (CCA). The previous attempts toward the CCA security rely on q-type assumptions, which are referred as non-static assumptions causing loose reduction in security proofs. In this paper, we provide a complete solution to the problem and show how to construct the continuous leakage-resilient IBE with weaker CCA security based on the dual system encryption technique, where the adversary is allowed to make continuous leakage queries. We are able to prove its security with static assumptions in the standard model. As a feature of our scheme, we allow leakage of multiple keys, i.e., leakage of the master secret key and the private key of user. Our scheme also enjoys better computational performance, since the round leakage parameter is independent of the plaintext space and has a constant size. Furthermore, our scheme can be easily extended to give the weaker CCA secure continuous leakage-resilient hierarchical identity-based encryption scheme with a short ciphertext length.

A Generic Approach to Build Revocable Hierarchical Identity-Based Encryption

Revocable hierarchical identity-based encryption (RHIBE) is an extension of HIBE that provides the efficient key revocation function by broadcasting an update key per each time period. Many RHIBE schemes have been proposed by combining an HIBE scheme and a tree-based revocation method, but a generic method for constructing an RHIBE scheme has not been proposed. In this paper, we show for the first time that it is possible to construct RHIBE schemes by generically combining underlying cryptographic primitives and tree-based revocation methods. We first generically construct an RHIBE-CS scheme by combining HIBE schemes and the complete subtree (CS) method, and prove the adaptive security by using the adaptive security of the HIBE schemes. Thus, we obtain RHIBE schemes under the quadratic residuosity assumption, CDH assumption, and factoring assumption. Next, we generically construct an RHIBE-SD scheme with shorter update keys by combining HIBE and hierarchical single revocation encryption (HSRE) schemes, and the subset difference (SD) method to reduce the size of update keys. Finally, we generically construct an RHIBE-CS scheme with shorter ciphertexts by combining HIBE schemes with constant-size ciphertext and the CS method. Through different kind of generic combinations, we obtain various RHIBE schemes that provide a trade-off between shorter ciphertexts and shorter update keys.

Wildcarded identity-based encryption from lattices

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.

Revocable hierarchical identity-based encryption with adaptive security

Hierarchical identity-based encryption (HIBE) can be extended to revocable HIBE (RHIBE) if a private key of a user can be revoked when the private key is revealed or expired. Previously, many selectively secure RHIBE schemes were proposed, but it is still unsolved problem to construct an adaptively secure RHIBE scheme. In this work, we propose two RHIBE schemes in composite-order bilinear groups and prove their adaptive security under simple static assumptions. To prove the adaptive security, we use the dual system encryption framework, but it is not simple to use the dual system encryption framework in RHIBE since the security model of RHIBE is quite different with that of HIBE. We show that it is possible to solve the problem of the RHIBE security proof by carefully designing hybrid games.

Adaptively secure revocable hierarchical IBE from k-linear assumption

Revocable identity-based encryption (RIBE) is an extension of IBE with an efficient key revocation mechanism. Revocable hierarchical IBE (RHIBE) is its further extension with key delegation functionality. Although there are various adaptively secure pairing-based RIBE schemes, all known hierarchical analogues only satisfy selective security. In addition, the currently known most efficient adaptively secure RIBE and selectively secure RHIBE schemes rely on non-standard assumptions, which are referred to as the augmented DDH assumption and q-type assumptions, respectively. In this paper, we propose a simple but effective design methodology for RHIBE schemes. We provide a generic design framework for RHIBE based on an HIBE scheme with a few properties. Fortunately, several state-of-the-art pairing-based HIBE schemes have the properties. In addition, our construction preserves the sizes of master public keys, ciphertexts, and decryption keys, as well as the complexity assumptions of the underlying HIBE scheme. Thus, we obtain the first RHIBE schemes with adaptive security under the standard k-linear assumption. We prove adaptive security by developing a new proof technique for RHIBE. Due to the compactness-preserving construction, the proposed R(H)IBE schemes have similar efficiencies to the most efficient existing schemes.

Identity-based Encryption from the Diffie-Hellman Assumption

We provide the first constructions of identity-based encryption and hierarchical identity-based encryption based on the hardness of the (Computational) Diffie-Hellman Problem (without use of groups with pairings) or Factoring. Our construction achieves the standard notion of identity-based encryption as considered by Boneh and Franklin [CRYPTO 2001]. We bypass known impossibility results using garbled circuits that make a non-black-box use of the underlying cryptographic primitives.

Edge-Based Blockchain Architecture for Event-Driven IoT using Hierarchical Identity Based Encryption

IoT (Internet of Things) sensors usually generate a large amount of data that is shared with a centralized cloud to provide various services. Traditional IoT architecture is heavily centralized, where data stored in a cloud environment is prone to several kinds of threats. As such, both data generated by sensors as well as IoT network shall be protected. Blockchain is an emerging technology that can be used in a wide spectrum of applications for better protection. However, the traditional blockchain protocol for Bitcoin cannot be used for IoT data protection because Bitcoin is a payment system, and the IoT ecosystem has a different architecture and requirements. Hence, more suitable blockchain architecture and encryption schemes for IoT are needed. In this paper, we propose a privacy-preserving blockchain architecture for IoT using Hierarchical Identity Based Encryption (HIBE). The proposed architecture fits well with event-driven IoT devices and uses the edge and the cloudlet computing paradigm as well as HIBE to preserve the privacy. Furthermore, the efficiency of the proposed architecture is demonstrated using a real-life case, namely, traffic speed radars. The security of the proposed architecture is analyzed and is verified through theoretical analysis that considers the existence of a malicious adversary. The performance of the proposed architecture is evaluated by conducting extensive experiments using the Contiki OS. The experimental results provide the system and network performance of the proposed architecture.

Algorithms for the Generalized NTRU Equations and their Storage Analysis

In LATTE, a lattice based hierarchical identity-based encryption (HIBE) scheme, each hierarchical level user delegates a trapdoor basis to the next level by solving a generalized NTRU equation of level ℓ ≥ 3. For ℓ = 2, Howgrave-Graham, Pipher, Silverman, and Whyte presented an algorithm using resultant and Pornin and Prest presented an algorithm using a field norm with complexity analysis. Even though their ideas of solving NTRU equations can be conceptually extended for ℓ ≥ 3, no explicit algorithmic extensions with the storage analysis are known so far. In this paper, we interpret the generalized NTRU equation as the determinant of a matrix. By using the mathematical properties of the determinant, we show that how to construct algorithms for solving the generalized NTRU equation either using resultant or a field norm for any ℓ ≥ 3. We also obtain an upper bound of the size of solutions by using the properties of the determinant. From our analysis, the storage requirement of the algorithm using resultant is O(ℓ2n2 logB) and that of the algorithm using a field norm is O(ℓ2n logB), where B is an upper bound of the coefficients of the input polynomials of the generalized NTRU equations. We present examples of our algorithms for ℓ = 3 and the average storage requirements for ℓ = 3; 4.

A generic construction for revocable identity-based encryption with subset difference methods.

To deal with dynamically changing user's credentials in identity-based encryption (IBE), providing an efficient key revocation method is a very important issue. Recently, Ma and Lin proposed a generic method of designing a revocable IBE (RIBE) scheme that uses the complete subtree (CS) method by combining IBE and hierarchical IBE (HIBE) schemes. In this paper, we propose a new generic method for designing an RIBE scheme that uses the subset difference (SD) method instead of using the CS method. In order to use the SD method, we generically design an RIBE scheme by combining IBE, identity-based revocation (IBR), and two-level HIBE schemes. If the underlying IBE, IBR, and HIBE schemes are adaptively (or selectively) secure, then our RIBE scheme is also adaptively (or selectively) secure. In addition, we show that the layered SD (LSD) method can be applied to our RIBE scheme and a chosen-ciphertext secure RIBE scheme also can be designed generically.

Tightly Secure Hierarchical Identity-Based Encryption

We construct the first tightly secure hierarchical identity-based encryption (HIBE) scheme basedon standard assumptions, which solves an open problem from Blazy, Kiltz, and Pan (CRYPTO 2014).At the core of our constructions is a novel randomization technique that enables us to randomizeuser secret keys for identities with flexible length.The security reductions of previous HIBEs lose at least a factor of Q, which is the number ofuser secret key queries. Different to that, the security loss of our schemes is only dependent onthe security parameter. Our schemes are adaptively secure based on the Matrix Diffie-Hellmanassumption, which is a generalization of standard Diffie-Hellman assumptions such as k-Linear. Wehave two tightly secure constructions, one with constant ciphertext size, and the other with tightersecurity at the cost of linear ciphertext size. Among other things, our schemes imply the first tightlysecure identity-based signature scheme by a variant of the Naor transformation.

Fully secure wicked identity-based encryption resilient to continual auxiliary- inputs leakage

To allow more general key derivation patterns, the concept of wicked identity-based encryption (wicked IBE) was introduced. It is an extension of hierarchical identity based encryption (HIBE). Recently, research on leakage-resilient wicked IBE has attracted much attention for its consideration on the problem of key leakage in system. However, the existing works implement leakage resistance under the bounded leakage model and fail to capture general form of leakage attacks. Through designing the generation of the master secret key and the user secret key reasonably, a wicked IBE scheme resilient to continual auxiliary-inputs leakage is proposed in this paper. The leakage of our scheme is not only from the user secret key, but also from the master secret key. We show the scheme is proven fully secure in the standard model based on the subgroup decision assumption in composite-order bilinear groups and the Goldreich-Levin theorem in Galois field. To achieve this goal, the dual system encryption technology is exploited in the security proof. Compared with existing leakage-resilient wicked IBE, our scheme has a better performance in leakage resilience and security.

ID-Based User-Centric Data Usage Auditing Scheme for Distributed Environments

Recent years have witnessed the trend of increasingly relying on remote and distributed infrastructures, mainly owned and managed by third parties. This increased the number of reported incidents of security breaches compromising users' personal data, where involved entities may massively collect and process massive amounts of such data. Toward these challenges, this paper combines hierarchical Identity Based Cryptographic (IBC) mechanisms with emerging blockchain technologies and introduces a blockchain-based data usage auditing architecture ensuring availability and accountability in a personal data-preserving fashion. The proposed approach relies on smart auditable contracts deployed in blockchain infrastructures. Thus, it offers transparent and controlled data access, sharing and processing, so that unauthorized entities cannot process data without data subjects' consent. Moreover, thanks to the usage of hierarchical ID-based encryption and signature schemes, the proposed solution protects and ensures the confidentiality of users' personal data shared with multiple data controllers and processors. It also provides auditing capacities with tamper-proof evidences for data usage compliance, supported by the intrinsic properties of the blockchain technology.