Paper 2020/619

Security Analysis of NIST CTR-DRBG

Viet Tung Hoang and Yaobin Shen

Abstract

We study the security of $\mathsf{CTR\text{-}DRBG}$, one of NIST's recommended Pseudorandom Number Generator (PRNG) designs. Recently, Woodage and Shumow (Eurocrypt' 19), and then Cohney et al. (S&P' 20) point out some potential vulnerabilities in both NIST specification and common implementations of $\mathsf{CTR\text{-}DRBG}$. While these researchers do suggest counter-measures, the security of the patched $\mathsf{CTR\text{-}DRBG}$ is still questionable. Our work fills this gap, proving that $\mathsf{CTR\text{-}DRBG}$ satisfies the robustness notion of Dodis et al. (CCS'13), the standard security goal for PRNGs.

Note: This is the full version of our paper.