Hierarchical Identity-based Encryption System Research Articles

Efficient Hierarchical Identity-Based Encryption System for Internet of Things Infrastructure

Security is a main concern for the Internet of Things (IoT) infrastructure as large volumes of data are collected and processed in the systems. Due to the limited resources of interconnected sensors and devices in the IoT systems, efficiency is one of the key considerations when deploying security solutions (e.g., symmetric/asymmetric encryption, authentication, etc.) in IoT. In this paper, we present an efficient Hierarchical Identity-Based Encryption (HIBE) system with short parameters for protecting data confidentiality in distributed IoT infrastructure. Our proposed HIBE system has the public parameters, private key, and ciphertext, each consisting of a constant number of group elements. We prove the full security of the HIBE system in the standard model using the dual system encryption technique. We also implement the proposed scheme and compare the performance with the original Lewko–Waters HIBE. To the best of our knowledge, our construction is the first HIBE system that achieves both full security in the standard model and short parameters in terms of the public parameters, private key, and ciphertext.

Identifier discrimination: realizing selective-ID HIBE with authorized delegation and dedicated encryption privacy

It has been almost one and a half decades since the introduction of the concept of hierarchical identity-based encryption (HIBE) systems, and many pairing-based HIBE systems have been proposed; however, how to achieve independent private key delegation in HIBE systems is still open. Independent private key delegation in HIBE systems requires that the following three conditions are satisfied: (1) private keys are not valid delegation credentials for deriving descendants’ private keys, (2) any entity intending to derive a private key for any one of its descendants should own a valid delegation credential distributed by the root private key generator (PKG), and (3) a credential is only valid for deriving private keys for a given descendant. We present a new technique for composing private keys for entities in HIBE systems that we call identifier discrimination, aiming at resolving the problem of independent private key delegation. With the technique, we construct a selective identity secure HIBE system under the decisional bilinear Diffie–Hellman (DBDH) assumption in the standard model with the following properties. (1) Every entity in the HIBE system is prevented from deriving private keys for its descendants with the only use of its private key and the public parameters. (2) The root PKG can delegate the privilege (if needed) of generating private keys for each individual entity to any of its ancestors through authorization that we call authorized delegation, by distributing a specifically crafted secret (delegation credential) to the ancestor. (3) The encryption privacy of each ciphertext for its intended recipient is achieved, that is, ciphertexts encrypted on identity of any entity cannot be decrypted by any of its ancestors that we call dedicated encryption privacy.

Differentiating Technique: Constructing Efficient HIBE with Constant Size Ciphertext and Authorized Delegation

As Hierarchical Identity Based Encryption (HIBE) system usually maps the true institutional structure of an organization or entity relationship between objects in real world, It is important that computation & communication complexity of private key, ciphertext, cryptographic computations and so on related to an entity in the hierarchy is independent to the hierarchy depth of the entity. Moreover, key escrow problem that any non-leaf entity in a hierarchical identity based cryptosystem can derive private keys for its descendants with use of its private key should be resolved, in order to prevent any entity from behaving on behalf of its descendants. In this paper, a new technique is introduced for composing a private key for each individual entity in HIBE system by differentiating between non-local identifiers and local identifiers of the identity of the entity. That we call Identifier Discrimination. With the technique, A selective identity secure HIBE system is constructed under Decisional Bilinear Diffie-Hellman (DBDH) assumption without using random oracles, where the private key and the ciphertext consist of constant number of group elements, and decryption requires only three bilinear map computations, regardless of the identity hierarchy depth. Moreover, in contrast to previous HIBE constructions, where private key for an entity can be derived by its ancestors with direct use of their private keys, key escrow problem inherent in identity based cryptosystems is resolved in our HIBE construction. Privilege of deriving private keys for an entity can be delegated to any of its ancestors through authorization by distributing specifically crafted values to the ancestor in our HIBE system, that we call Authorized Delegation.

Anonymous hierarchical identity-based encryption without key delegation in decryption

Hierarchical identity-based encryption (HIBE) introduces the concept of hierarchical identity in identity-based encryption (IBE) which eases the burden of key generation centre. Anonymous identity-based encryption is another extension of IBE in which the ciphertext leaks no information about the target identity. In this paper, we propose a new anonymous hierarchical identity-based encryption system. Unlike previous anonymous HIBE system, our system needs no key delegation in decryption, i.e., the user can decrypt the ciphertext directly if his identity vector is the prefix of the target identity vector. So it is not necessary for the user to know the target identity vector, which enhances the practicality of anonymous HIBE systems. Our system is constructed in composite order groups and proven adaptive security and anonymity from four static assumptions by using the dual system encryption technique.