Qingni Shen

Fully secure unidirectional identity-based proxy re-encryption

Proxy re-encryption (PRE) allows the proxy to translate a ciphertext encrypted under Alices public key into another ciphertext that can be decrypted by Bobs secret key. Identity-based proxy re-encryption (IB-PRE) is the development of identity-based encryption and proxy re-encryption, where ciphertexts are transformed from one identity to another. In this paper, we propose two novel unidirectional identity-based proxy re-encryption schemes, which are both non-interactive and proved secure in the standard model. The first scheme is a single-hop IB-PRE scheme and has master secret security, allows the encryptor to decide whether the ciphertext can be re-encrypted. The second scheme is a multi-hop IB-PRE scheme which allows the ciphertext re-encrypted multiple times but without the size of ciphertext growing linearly as previous multi-hop IB-PRE schemes.

Securing data services: a security architecture design for private storage cloud based on HDFS

With the growth of business, an enterprise would like to make its PSC private storage cloud approach an infrastructure service in a partner/public cloud. In such PSCs, there are some new data security issues, First, how to keep the data rest in the PSC isolated from internal and external attackers; second, how to make secure intra-cloud data migration within the enterprise; third, how to secure inter-cloud data migrating between the PSC and the partner/public cloud. In this paper, we propose an architecture design for enforcing data security services on the layer of HDFS in the PSC, including secure data isolation service, secure intra-cloud data migration service, and secure inter-cloud data migration service. Finally, it gives the prototype implemented as pluggable security modules in accord with our custom security policies through AOP Aspect-Oriented Programming method. The time cost is given and evaluated efficiently.

SAPSC: Security Architecture of Private Storage Cloud Based on HDFS

With the growth of business, an enterprise would like to make its PSC(private storage cloud) approach an infrastructure service in a Partner/Public Cloud. In such PSCs, there are some new security issues, First, how to isolate the data stored in the PSC from internal and external attackers, Second, how to make secure intra-cloud data migration within an enterprise, Third, how to secure inter-cloud data migration between the PSC and the Partner/Public Cloud. In this paper, we propose an architecture of enforcing security services on the layer of HDFS, including Data Isolation Service, Secure Intra-Cloud Data Migration Service, and Secure Inter-Cloud Data Migration Service. Finally, a prototype has been implemented based on HDFS by our three custom security policies, and the time cost is given and evaluated.

SecDM: Securing Data Migration between Cloud Storage Systems

with the development of cloud computing, cloud security issues have recently gained traction in the research community. Although much of the efforts are focused on securing the operation system and virtual machine, or securing data storage inside a cloud system, this paper takes an alternative perspective to cloud security-the security of data migration between different clouds. First, we describe some threats when we are doing data migration. Second, we propose a security mechanism to deal with the security issues on data migration from one cloud to another. Third, we design a prototype to give the mechanism a brief implementation based on HDFS(Hadoop Distributed File System) and we do a series of tests to evaluate our prototype. Here, the solutions to securing data migration between clouds mainly involve in SSL negotiation, migration ticket design and block encryption in distributed file system and cluster parallel computing.

Optimization of covert channel identification

We characterize the properties of covert channels and present a taxonomy of covert channels. Information flow sequence is adopted to represent information flows and covert channels. Covert channels are categorized according to their information flow characteristics. On this basis, we explore the optimization of covert channel identification with the shared resource matrix method adopted for demonstration. A general framework for covert channel identification founded on information flow analysis is proposed. We also review previous work within our framework. The application of our approach to a practical system is shown. At last, a new class of covert channels which used to be omitted by previous work is introduced

A way of key management in cloud storage based on trusted computing

Cloud security has gained increasingly emphasis in the research community, with much focus primary concentrated on how to secure the operation system and virtual machine on which cloud system runs on. We take an alternative perspective to consider the problem of building a secure cloud storage service on top of a public cloud infrastructure where the service provider is not completely trusted by the customer. So, it is necessary to put cipher text into the public cloud. We describe an architecture based on Trusted Platform Module and the client of cloud storage system to help manage the symmetric keys used for encrypting data in the public cloud and the asymmetric keys used for encrypting symmetric keys. The key management mechanism includes how to store keys, how to backup keys, and how to share keys. Based on the HDFS (Hadoop Distributed File System), we put a way of key management into practice, and survey the benefits that such an infrastructure will provide to cloud users and providers, and we also survey the time cost it will bring to us.

Covert channel identification founded on information flow analysis

This paper focuses on covert channel identification in a nondiscretionary secure system. The properties of covert channels are analyzed by channel types. Information flow characteristics are utilized to optimize channel identification with the Share Resource Matrix method adopted for demonstration, and a general framework for channel identification founded on information flow analysis is presented. At last, timing channels are also discussed.

Ciphertext-Policy Attribute-Based Encryption with User and Authority Accountability

To ensure the security of sensitive data, people need to encrypt them before uploading them to the public storage. Attribute-based encryption (ABE) is a promising cryptographic primitive for fine-grained sharing of encrypted data. However, ABE lacks user and authority accountability. The user can share his/her secret key without being identified, while key generation center (KGC) can generate any user’s secret key. In this paper, we propose a practical large universe ciphertext-policy ABE (CP-ABE) with user and authority accountability in the white-box model. As embedding the user’s identity information into this user’s secret key directly, the trace stage has only O(1) time overhead. The property of accountability is proved against the dishonest user and KGC in the standard model. We implement our scheme in Charm. Experiments show that CP-ABE of Rouselakis and Waters in CCS 2013 is enhanced in user and authority accountability by our method with small computational cost.

A Generalized Trusted Virtualized Platform Architecture

Problems of overall safety management, appropriate load balance, and the need for easy-to-use emerge in an environment containing multiple trusted virtualized platforms. We proposed the generalized trusted virtualized platform architecture, GTVP, which combines multiple physical platforms as a trusted union. GTVP first establishes trust relationship among all platforms, and then synchronizes their resource and security information for unified management. Moreover, GTVP supports fast and secure migration to resolve the overall load-balance issue. Host OS (as in Xen) of GTVP is divided into five control domains for minimizing TCB and guest OS of certain application (called as Lazy Box) cut into components for rapid deployment and upgrade. As a result, administrators can manage multiple platforms in a similar way as in a single platform and get the benefits of security, efficiency and easy-to-use while obtaining transparency and flexibility. Three scenarios are demonstrated to show their efficiency in the GTVP architecture.

A practical construction for large universe hierarchical attribute‐based encryption

We present a practical large universe hierarchical attribute‐based encryption (LU‐HABE) scheme, which supports monotone access structures. In our system, key generation centers (KGCs), any one in which is labeled by a unique identity, are organized as a hierarchical structure. Thus, all secret keys issued by the KGC contain 2 parts: the identity‐related one and the attribute‐related one. Once the data owner wants to encrypt his/her data, he/she needs to specify certain numbers of pairs according to his/her demand. The pair consists of an identity of a KGC and a policy of attributes managed by the corresponding KGC, eg, IDi and (Mi, ρi). If and only if an identity associated with users secret key is equal to or is an ancestor of one of the identities appearing in ciphertext, and simultaneously a set of attributes belonging to the user satisfies the policy, the user can decrypt it successfully. Our scheme is proved to be selectively secure in the standard model under the modified “q‐type” assumption similar to the ones used in former works and is extended to support online/offline encryption. To show the efficiency of our construction, we implement our original scheme and the extended one in Charm. Analyses show that both of them are very practical.