Biblio

The Trusted Platform Module (TPM) is an international standard for a security chip that can be used for the management of cryptographic keys and for remote attestation. The specification of the most recent TPM 2.0 interfaces for direct anonymous attestation unfortunately has a number of severe shortcomings. First of all, they do not allow for security proofs (indeed, the published proofs are incorrect). Second, they provide a Diffie-Hellman oracle w.r.t. the secret key of the TPM, weakening the security and preventing forward anonymity of attestations. Fixes to these problems have been proposed, but they create new issues: they enable a fraudulent TPM to encode information into an attestation signature, which could be used to break anonymity or to leak the secret key. Furthermore, all proposed ways to remove the Diffie-Hellman oracle either strongly limit the functionality of the TPM or would require significant changes to the TPM 2.0 interfaces. In this paper we provide a better specification of the TPM 2.0 interfaces that addresses these problems and requires only minimal changes to the current TPM 2.0 commands. We then show how to use the revised interfaces to build q-SDH-and LRSW-based anonymous attestation schemes, and prove their security. We finally discuss how to obtain other schemes addressing different use cases such as key-binding for U-Prove and e-cash.

Just as cloud customers have different performance requirements, they also have different security requirements for their computations in the cloud. Researchers have suggested a "security on demand" service model for cloud computing, where secure computing environment are dynamically provisioned to cloud customers according to their specific security needs. The availability of secure computing platforms is a necessary but not a sufficient solution to convince cloud customers to move their sensitive data and code to the cloud. Cloud customers need further assurance to convince them that the security measures are indeed deployed, and are working correctly. In this paper, we present Policy-Customized Trusted Cloud Service architecture with a new remote attestation scheme and a virtual machine migration protocol, where cloud customer can custom security policy of computing environment and validate whether the current computing environment meets the security policy in the whole life cycle of the virtual machine. To prove the availability of proposed architecture, we realize a prototype that support customer-customized security policy and a VM migration protocol that support customer-customized migration policy and validation based on open source Xen Hypervisor.

Compared to other remote attestation methods, the binary-based approach is the most direct and complete one, but privacy protection has become an important problem. In this paper, we presented an Extended Hash Algorithm (EHA) for privacy protection based on remote attestation method. Based on the traditional Merkle Hash Tree, EHA altered the algorithm of node connection. The new algorithm could ensure the same result in any measure order. The security key is added when the node connection calculation is performed, which ensures the security of the value calculated by the Merkle node. By the final analysis, we can see that the remote attestation using EHA has better privacy protection and execution performance compared to other methods.

Remote attestation is a crucial security service particularly relevant to increasingly popular IoT (and other embedded) devices. It allows a trusted party (verifier) to learn the state of a remote, and potentially malware-infected, device (prover). Most existing approaches are static in nature and only check whether benign software is initially loaded on the prover. However, they are vulnerable to runtime attacks that hijack the application's control or data flow, e.g., via return-oriented programming or data-oriented exploits. As a concrete step towards more comprehensive runtime remote attestation, we present the design and implementation of Control-FLow ATtestation (C-FLAT) that enables remote attestation of an application's control-flow path, without requiring the source code. We describe a full prototype implementation of C-FLAT on Raspberry Pi using its ARM TrustZone hardware security extensions. We evaluate C-FLAT's performance using a real-world embedded (cyber-physical) application, and demonstrate its efficacy against control-flow hijacking attacks.

Prior remote attestation may not be suitable to scale to the proliferation of IoT device swarms. To this end, we propose a cooperative remote attestation scheme, which validates the security state and verifies the system integrity with the cooperation of neighbor devices. The efficiency of the proposed mechanism is analyzed as a cryptographic protocol and then discussed in terms of security and scalability.

Anti-tampering is a form of software protection conceived to detect and avoid the execution of tampered programs. Tamper detection assesses programs' integrity with load or execution-time checks. Avoidance reacts to tampered programs by stopping or rendering them unusable. General purpose reactions (such as halting the execution) stand out like a lighthouse in the code and are quite easy to defeat by an attacker. More sophisticated reactions, which degrade the user experience or the quality of service, are less easy to locate and remove but are too tangled with the program's business logic, and are thus difficult to automate by a general purpose protection tool. In the present paper, we propose a novel approach to anti-tampering that (i) fully automatically applies to a target program, (ii) uses Remote Attestation for detection purposes and (iii) adopts a server-side reaction that is difficult to block by an attacker. By means of Client/Server Code Splitting, a crucial part of the program is removed from the client and executed on a remote trusted server in sync with the client. If a client program provides evidences of its integrity, the part moved to the server is executed. Otherwise, a server-side reaction logic may (temporarily or definitely) decide to stop serving it. Therefore, a tampered client application can not continue its execution. We assessed our automatic protection tool on a case study Android application. Experimental results show that all the original and tampered executions are correctly detected, reactions are promptly applied, and execution overhead is on an acceptable level.

Large numbers of smart connected devices, also named as the Internet of Things (IoT), are permeating our environments (homes, factories, cars, and also our body - with wearable devices) to collect data and act on the insight derived. Ensuring software integrity (including OS, apps, and configurations) on such smart devices is then essential to guarantee both privacy and safety. A key mechanism to protect the software integrity of these devices is remote attestation: A process that allows a remote verifier to validate the integrity of the software of a device. This process usually makes use of a signed hash value of the actual device's software, generated by dedicated hardware. While individual device attestation is a well-established technique, to date integrity verification of a very large number of devices remains an open problem, due to scalability issues. In this paper, we present SANA, the first secure and scalable protocol for efficient attestation of large sets of devices that works under realistic assumptions. SANA relies on a novel signature scheme to allow anyone to publicly verify a collective attestation in constant time and space, for virtually an unlimited number of devices. We substantially improve existing swarm attestation schemes by supporting a realistic trust model where: (1) only the targeted devices are required to implement attestation; (2) compromising any device does not harm others; and (3) all aggregators can be untrusted. We implemented SANA and demonstrated its efficiency on tiny sensor devices. Furthermore, we simulated SANA at large scale, to assess its scalability. Our results show that SANA can provide efficient attestation of networks of 1,000,000 devices, in only 2.5 seconds.

Based on the analysis relationships of challenger and attestation in remote attestation process, we propose a dynamic remote attestation model based on concerns. By combines the trusted root and application of dynamic credible monitoring module, Convert the Measurement for all load module of integrity measurement architecture into the Attestation of the basic computing environments, dynamic credible monitoring module, and request service software module. Discuss the rationality of the model. The model used Merkel hash tree to storage applications software integrity metrics, both to protect the privacy of the other party application software, and also improves the efficiency of remote attestation. Experimental prototype system shows that the model can verify the dynamic behavior of the software, to make up for the lack of static measure.

A web service is a web-based application connected via the internet connectivity. The common web-based applications are deployed using web browsers and web servers. However, the security of Web Service is a major concern issues since it is not widely studied and integrated in the design stage of Web Service standard. They are add-on modules rather a well-defined solutions in standards. So, various web services security solutions have been defined in order to protect interaction over a network. Remote attestation is an authentication technique proposed by the Trusted Computing Group (TCG) which enables the verification of the trusted environment of platforms and assuring the information is accurate. To incorporate this method in web services framework in order to guarantee the trustworthiness and security of web-based applications, a new framework called TrustWeb is proposed. The TrustWeb framework integrates the remote attestation into SSL/TLS protocol to provide integrity information of the involved endpoint platforms. The framework enhances TLS protocol with mutual attestation mechanism which can help to address the weaknesses of transferring sensitive computations, and a practical way to solve the remote trust issue at the client-server environment. In this paper, we describe the work of designing and building a framework prototype in which attestation mechanism is integrated into the Mozilla Firefox browser and Apache web server. We also present framework solution to show improvement in the efficiency level.