Strong identity-based proxy signature schemes, revisited

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Proxy Signature Scheme with Effective Revocation Using Bilinear Pairings

We present a proxy signature scheme using bilinear pairings that provides effective proxy revocation. The scheme uses a binding-blinding technique to avoid secure channel requirements in the key issuance stage. With this technique, the signer receives a partial private key from a trusted authority and unblinds it to get his private key, in turn, overcomes the key escrow problem which is a constraint in most of the pairing-based proxy signature schemes. The scheme fulfills the necessary security requirements of proxy signature and resists other possible threats

On Using Encryption Techniques to Enhance Sticky Policies Enforcement

How to enforce privacy policies to protect sensitive personal data has become an urgent research topic for security researchers, as very little has been done in this field apart from some ad hoc research efforts. The sticky policy paradigm, proposed by Karjoth, Schunter, and Waidner, provides very useful inspiration on how we can protect sensitive personal data, but the enforcement is very weak. In this paper we provide an overview of the state of the art in enforcing sticky policies, especially the concept of sticky policy enforcement using encryption techniques including Public-Key Encryption (PKE), Identity-Based Encryption (IBE), Attribute-Based Encryption (ABE), and Proxy Re-Encryption (PRE). We provide detailed comparison results on the (dis)advantages of these enforcement mechanisms. As a result of the analysis, we provide a general framework for enhancing sticky policy enforcement using Type-based PRE (TPRE), which is an extension of general PRE

Certificateless Signature Scheme Based on Rabin Algorithm and Discrete Logarithm

Certificateless signature can effectively immue the key escrow problem in the identity-based signature scheme. But the security of the most certificateless signatures usually depends on only one mathematical hard problem, which makes the signature vulnerable when the underlying hard problem has been broken. In order to strengthen the security, in this paper, a certificateless signature whose security depends on two mathematical hard problems, discrete logarithm and factoring problems, is proposed. Then, the proposed certificateless signature can be proved secure in the random oracle, and only both of the two mathematical hard problems are solved, can the proposed signature be broken. As a consequence, the proposed certificateless signature is more secure than the previous signatures. On the other hand, with the pre-computation of the exponential modular computation, it will save more time in the signature signing phase. And compared with the other schemes of this kind, the proposed scheme is more efficient

Cost-effective secure e-health cloud system using identity based cryptographic techniques

Nowadays E-health cloud systems are more and more widely employed. However the security of these systems needs more consideration for the sensitive health information of patients. Some protocols on how to secure the e-health cloud system have been proposed, but many of them use the traditional PKI infrastructure to implement cryptographic mechanisms, which is cumbersome for they require every user having and remembering its own public/private keys. Identity based encryption (View the MathML sourceIBE) is a cryptographic primitive which uses the identity information of the user (e.g., email address) as the public key. Hence the public key is implicitly authenticated and the certificate management is simplified. Proxy re-encryption is another cryptographic primitive which aims at transforming a ciphertext under the delegator AA into another ciphertext which can be decrypted by the delegatee BB. In this paper, we describe several identity related cryptographic techniques for securing E-health system, which include new View the MathML sourceIBE schemes, new identity based proxy re-encryption (View the MathML sourceIBPRE) schemes. We also prove these schemes’ security and give the performance analysis, the results show our View the MathML sourceIBPRE scheme is especially highly efficient for re-encryption, which can be used to achieve cost-effective cloud usage.Peer ReviewedPostprint (author's final draft

Efficient cryptographic primitives: Secure comparison, binary decomposition and proxy re-encryption

”Data outsourcing becomes an essential paradigm for an organization to reduce operation costs on supporting and managing its IT infrastructure. When sensitive data are outsourced to a remote server, the data generally need to be encrypted before outsourcing. To preserve the confidentiality of the data, any computations performed by the server should only be on the encrypted data. In other words, the encrypted data should not be decrypted during any stage of the computation. This kind of task is commonly termed as query processing over encrypted data (QPED). One natural solution to solve the QPED problem is to utilize fully homomorphic encryption. However, fully homomorphic encryption is yet to be practical. The second solution is to adopt multi-server setting. However, the existing work is not efficient. Their implementations adopt costly primitives, such as secure comparison, binary decomposition among others, which reduce the efficiency of the whole protocols. Therefore, the improvement of these primitives results in high efficiency of the protocols. To have a well-defined scope, the following types of computations are considered: secure comparison (CMP), secure binary decomposition (SBD) and proxy re-encryption (PRE). We adopt the secret sharing scheme and paillier public key encryption as building blocks, and all computations can be done on the encrypted data by utilizing multiple servers. We analyze the security and the complexity of our proposed protocols, and their efficiencies are evaluated by comparing with the existing solutions.”--Abstract, page iii