隨著科技的發展，使用者越來越重視資料的安全性與隱私，以資料的儲存來說NAND Flash Memory具有體積小、高抗震性、低功耗及快速儲存等優點，成為目前手機的主要儲存設備。Flash Memory相較於傳統硬碟(Hard Disk Drive)來說，在資料抹除(Data Erasure)方面有很大的不同，傳統硬碟可以針對讀寫的最小單位磁區(Sector)進行抹除的動作，而Flash Memory因為硬體上的限制，最小的抹除單位是區塊(Block)，區塊是由最小的讀寫單位頁面(Page)所組成的。其中，Flash Memory必須透過快閃記憶體轉換層(Flash Translation Layer)中的垃圾資料回收機制(Garbage Collection)來達到真正抹除資料的動作。在近幾年的研究中，傳統硬碟的標準抹除演算法(Data Erasure Standard)是利用覆寫(Overwriting)最小單位磁區(Sector)來達到抹除磁性，使資料難以被辨別，進而達到抹除資料的效果，但Flash Memory的讀寫及抹除機制與傳統硬碟不同，因此，本文將驗證傳統硬碟上的標準抹除演算法(Data Erasure Standard)在NAND Flash Memory中是否達到完整抹除資料的效果。

Recently, NAND flash memory has been widely used in cell phones because of its small size, non-volatility feature, shock resistance, low-power consumption, and fast access speed. Data security is an important issue for the users. There is a different erase operation between Flash memory and Hard Disk Drive. And traditional overwriting algorithms are used on flash memory, which are used on HDD. These overwriting algorithms are not verified on flash memory. Thus, we are going to verify all of overwriting algorithms whether to work on flash memory or not. In the thesis, we will verify erase algorithms on different garbage collections and propose a method of complete erase data for NAND flash memory.

D. Defense, National Industrial Security Program Operating Manual (NISPOM), US, 2011.
P. Gutmann, "Data Remanence in Semiconductor Devices," in USENIX Security Symposium - Volume 10, Washington, D.C., 2001.
A. Ban, "“Flash file system". US Patent Patent 5404485A, April 1995.
A. Ban, "Flash file system optimized for page-mode flash technologies". US Patent Patent 5937425 A, Aug 1999.
Jesung Kim, Jong Min Kim, S. H. Noh, Sang Lyul Min, Yookun Cho, "A space efficient flash translation layer for CompactFlash systems," in IEEE Transactions on Consumer Electronics, pp. 366-375, May 2002.
Michael Wu, Willy Zwaenepoel, "eNVy: a non-volatile, main memory storage system," in ASPLOS VI Proceedings of the sixth international conference on Architectural support for programming languages and operating systems, San Jose, California, USA, 1994.
Mendel Rosenblum, John K. Ousterhout, "The design and implementation of a log-structured file system," ACM Transactions on Computer Systems (TOCS), pp. Pages 26-52 , 1 Feb 1992.
M.-L. Chiang, R.-C. Chang, "Cleaning policies in mobile computers using flash memory," Journal of Systems and Software, pp. Pages 213-231 , 1 Nov 1999.
Michael Wei, Laura M. Grupp, Frederick E. Spada, Steven Swanson, "Reliably erasing data from flash-based solid state drives," in FAST'11 Proceedings of the 9th USENIX conference on File and stroage technologies, San Jose, California, 2011.
S. Skorobogatov, "Data Remanence in Flash Memory Devices," in international conference on Cryptographic hardware and embedded systems, Edinburgh, UK, 2005.
Mohammad Tehranipoor, Cliff Wang, Introduction to Hardware Security and Trust, Springer Publishing Company, Incorporated ©2011 , 2011.
L. L. J. B. Kim Vaisanen, "Apparatus, a system, a method and a computer program for erasing data stored on a storage device". US Patent Patent US9286231B2, 05 07 2012.
Jens Axboe, Alan D. Brunelle, blktrace User Guide, US, 2008.
Aayush Gupta, Youngjae Kim, Bhuvan Urgaonkar, "DFTL: a flash translation layer employing demand-based selective caching of page-level address mappings," in Architectural support for programming languages and operating systems, New York, NY, USA, 2009.
P. Gutmann, "Secure deletion of data from magnetic and solid-state memory," in SSYM'96 Proceedings of the 6th conference on USENIX Security Symposium, Focusing on Applications of Cryptography - Volume 6, San Jose, California, 1996.
B. Schneier, "Schneier on Security," 2004. [Online]. Available: https://www.schneier.com/.
C. S. Establishment, Clearing and Declassifying Electronic Data Storage Devices, Canada: Communications Security Establishment , 2000.
A. Government, Information Security Management, Australian, 2014.
U. G. C. Headquarters, HMG IA/IS 5 Secure Sanitisation of Protectively Marked Information or Sensitive Information, UK: Communications-Electronics Security Group, 2014.
Richard Kissel, Andrew Regenscheid, Matthew Scholl, Kevin Stine, Guidelines for Media Sanitization, US: National Institute of Standards and Technology, December 2014.