Unbalanced tree‐formed verification data for trusted platforms

Abstract

Validation is an alternative approach to the establishment of the trust between two or more entities. The validation allows a challenger to evaluate the trustworthiness of an attesting system based on provided evidence. Early attempts show the evidence is always organized in a linear structure or a balanced tree. These methods, however, are not optimal when facing a complex system and privacy issues. In particular, the Stored Measurement Log (SML) to record the execution history of the attesting system brings efficiency, scalability and privacy problems. We attempt to mitigate them through a new algorithm that uses an unbalanced tree to manage the SML. Leaves represent measurement values of components, and the root is protected by platform configuration registers, which is the same as the balanced tree. The location of each node, however, is constantly mutative until the probability distribution of all components tends towards stabilization. The greater the probability of the leaf is, the closer it is to the root, which benefits the validation. We build a prototype program that is developed through the Trusted Platform Module emulator 0.7. We touch on some mechanisms to reduce the size of the tree and avoid privacy leak. Finally, we perform an in-depth analysis of the validation efficiency, and present the impression of the time complexity of the measurement. Results show that the validation obtains the logarithmic speed-up (O((n/N)lb(n))) and that the time complexity of the measurement process is also acceptable. Besides, our scheme demonstrates advantages in privacy protection and scalability.

Mutual authentication‐based RA scheme for embedded systems

“…In this section, we present the evaluation on the integrity attestation of our scheme. We compare the efficiency of LPBHT with Xu et al's [26] Merkle hash tree (MHT), Zhang et al's Enhanced-MHT (E-MHT) [27], and Fu et al's stored measurement log (UBTS-SML) [29], both of which are configuration-based RA scheme and work for better efficiency. The MHT is an integrity measurement hash-tree scheme based on a balanced binary tree (BBT), which is a static measurement scheme with a very high attestation efficiency.…”

“…7c shows that as the number of updated nodes increases from 40 to 600 at the same time, the average updated path depth rises from 5 to 8, which is far more shortened than the depth value 14 in BBT. At last, we assume n at a [26] high static none high E-MHT [27] high dynamic low high UBTS-SML [29] high dynamic low high this paper high dynamic high high typical value, which is 8. With the strength of local principle iol increases, the efficiency of the RA is becoming better and better, which is shown in Fig.…”

“…Although the construction of the hash tree is optimised and the construction time of the hash tree is reduced, the model fails to improve the verification efficiency of RA. Taking into account of the access frequency of applications, Fu et al [29] proposed an UnBalanced Tree Scheme (UBTS)-stored measurement log (SML) construction method for unbalanced hash tree (UHT), which improved the verification efficiency of RA. However, this method needs to update the structure of the tree for each application request.…”

Remote Attestation on Behavioral Traces for Crowd Quality Control Based on Trusted Platform Module

“…is promising technique can provide two important services, namely, secure storage and platform attestation. In recent years, we have conducted several studies [23][24][25][26] on platform attestation and its application. As another technical branch addressing the issue, a trusted environment is isolated in the CPU [27,28].…”

TZ-MRAS: A Remote Attestation Scheme for the Mobile Terminal Based on ARM TrustZone

“…e Merkle hash tree is a fundamental technology in remote verification, which is flexible and protects privacy. Many research studies have proposed to assign different weights to the hash tree leaf nodes to achieve a better model [13,14]. However, the prior has not offered a feasible algorithm to compute and update the weight of each leaf node.…”