Security requirements for real-life applications still increase. For this purpose, many people develop cryptographic protocols in order to fulfill these needs. When someone designs a new protocol, he usually uses cryptographic tools for which he is confident. The design and the analysis of these tools is the domain
Many cryptographic protocols secure against malicious players use specially designed cryptographic tools. Essentially, these special tools function much like less-expensive tools, but give extra ‘powers’ to a reduction or simulation algorithm. Using these powers, cryptographers can construct a proof of security using standard techniques. However, these powers are not available to either the honest parties or the adversary. In a large class of protocols, by replacing the expensive, specially designed cryptographic tool with a corresponding less-expensive tool, we can improve the protocol’s efficiency without changing the functionality available to either the adversary or the honest parties. The key motivating question we address in this paper is whether the new, ‘substituted’ protocol is still secure. We introduce a framework for reasoning about this question. Our framework uses translators: special purpose oracles that map outputs of one cryptographic tool to corresponding outputs of a different tool. Translators are similar to, but generally weaker than, the “angels” of Prabhakaran and Sahai [29]. We introduce the notion of substitution-friendly protocols and show that such protocols remain secure after substitution in our framework. We also leverage existing proofs of security; there is no need to re-prove security from scratch. We demonstrate our framework with a non-interactive non-malleable bit commitment protocol.
In recent years, wireless sensor networks (WSNs) have been extensively used in many fields, which provide great convenience for people’s daily work and life. With the popularity of WSNs, people’s demands for related authentication protocols are developing in a comprehensive and perfect direction, and relevant designs are focusing more on two aspects: security and performance. However, current research cannot avoid the problem that security and efficiency are not compatible. Some studies use time-consuming cryptographic structures for security, while most lightweight schemes are designed without considering certain security properties, such as perfect forward secrecy, the resistance to known session-specific temporary information attack, etc. In our view, this conflict can be resolved by using lightweight cryptography primitives with special attention to protocol vulnerabilities and ever-evolving security requirements of people. By abandoning all unnecessary cryptographic structures, we propose a comprehensive lightweight three-factor authentication protocol with various security requirements, including adaptive privacy preservation, which is suitable for the user-friendly scenario in the WSN. Through security analysis, real-or-random (ROR) model proof, Automated Validation of Internet Security Protocols and Applications experimental verification, and security aspect comparison, it is proved that our protocol is superior in the security aspect. The performance experiment under MIRACL library shows that this study has advantages in performance compared with other recent research.
Assume that several people wish to have a meeting. For this to happen, they usually have to meet somewhere. If they cannot meet physically, then they can take part in a video (or audio) conference to discuss whatever needs to be discussed. But what if their meeting is meant to be private? In this case they need a cryptographic protocol that allows them to exchange their ideas remotely, while keeping them secure from any potential eavesdropper. In this paper we list all the necessary requirements that a cryptographic protocol must have in order to allow several persons to exchange their ideas securely over the Internet. Moreover, and based on the standard taxonomy of cryptographic protocols, we suggest several approaches on how to design cryptographic protocols that enable us to achieve our aim. Finally, we propose the design of a protocol that solves our problem.