Random Number Generation From 3D-NAND Flash Memory Using Shallow Charge Trap Related Short-Term Retention Errors
Ruibin Zhou, Jian Huang, Xianping Liu, Yuhan Wang, Xinrui Zhang, Yungen Peng, Zhiyi Yu · 2024
Read noise and operation latency variation are major sources of entropy in existing flash memory-based True Random Number Generators (TRNGs). We proposed that the short-term retention errors caused by the charging and discharging of shallow traps in 3D-NAND flash memory can serve as entropy for TRNGs. By utilizing the back-pattern effect and bypassing the intrinsic determinacy of the design and process of 3D-NAND flash memory, we developed a method with only normal user operations for random number extraction. Using this method, we successfully extracted random bitstreams without post-debiasing process. We evaluated the randomness of the generated bitstream using the NIST SP 800–22 statistical test suite and it passed all 15 tests. This method can be conveniently implemented in electrical systems that use 3D NAND flash memory as a storage medium.