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Xiao, Tianran, Tong, Wei, Lei, Xia, Liu, Jingning, Liu, Bo.  2019.  Per-File Secure Deletion for Flash-Based Solid State Drives. 2019 IEEE International Conference on Networking, Architecture and Storage (NAS). :1—8.

File update operations generate many invalid flash pages in Solid State Drives (SSDs) because of the-of-place update feature. If these invalid flash pages are not securely deleted, they will be left in the “missing” state, resulting in leakage of sensitive information. However, deleting these invalid pages in real time greatly reduces the performance of SSD. In this paper, we propose a Per-File Secure Deletion (PSD) scheme for SSD to achieve non-real-time secure deletion. PSD assigns a globally unique identifier (GUID) to each file to quickly locate the invalid data blocks and uses Security-TRIM command to securely delete these invalid data blocks. Moreover, we propose a PSD-MLC scheme for Multi-Level Cell (MLC) flash memory. PSD-MLC distributes the data blocks of a file in pairs of pages to avoid the influence of programming crosstalk between paired pages. We evaluate our schemes on different hardware platforms of flash media, and the results prove that PSD and PSD-MLC only have little impact on the performance of SSD. When the cache is disabled and enabled, compared with the system without the secure deletion, PSD decreases SSD throughput by 1.3% and 1.8%, respectively. PSD-MLC decreases SSD throughput by 9.5% and 10.0%, respectively.

Fan, Yongkai, Zhao, Guanqun, Sun, Xiaofeng, Wang, Jinghan, Lei, Xia, Xia, Fanglue, Peng, Cong.  2019.  A Security Scheme for Fog Computing Environment of IoT. Proceedings of the 2nd International ACM Workshop on Security and Privacy for the Internet-of-Things. :58–59.

As an extension of cloud computing, fog computing environment as well as fog node plays an increasingly important role in internet of things (IoT). This technology provides IoT with more distributed and efficient applications and services. However, IoT nodes have so much variety and perform poorly, which leads to more security issues. For this situation, we initially design a security scheme for the IoT fog environment. Based on the combination of Blockchain and Trusted Execution Environment (TEE) technologies, the security of data storage and transmission from fog nodes to the cloud are ensured, thus ensuring the trustworthiness of the data source in the fog environment.