Edward Snowden 再次丟出 NSA 內部文件，表示 NSA 付錢給 RSA 在演算法裡面放後門：「Exclusive: Secret contract tied NSA and security industry pioneer」。
RSA 的回應則是完全不想提到這筆錢是做什麼用的：「RSA Response to Media Claims Regarding NSA Relationship」。
現在一般在猜測，這個後門應該就是 RSA BSAFE 的預設偽隨機數產生器 Dual_EC_DRBG。
對於 Dual_EC_DRBG 的攻擊，2006 年的「Cryptanalysis of the Dual Elliptic Curve Pseudorandom Generator」就這樣寫：
Our experimental results and also empirical argument show that the DEC PRG is insecure. The attack does not imply solving the ECDLP for the corresponding elliptic curve. The attack is very efficient.
在 2007 年，Bruce Schneier 寫了一篇「Did NSA Put a Secret Backdoor in New Encryption Standard?」，提到這個弱點並沒有大到使得這個演算法不堪用，但看了總是不爽：
Problems with Dual_EC_DRBG were first described in early 2006. The math is complicated, but the general point is that the random numbers it produces have a small bias. The problem isn't large enough to make the algorithm unusable -- and Appendix E of the NIST standard describes an optional work-around to avoid the issue -- but it's cause for concern. Cryptographers are a conservative bunch: We don't like to use algorithms that have even a whiff of a problem.
My recommendation, if you're in need of a random-number generator, is not to use Dual_EC_DRBG under any circumstances. If you have to use something in SP 800-90, use CTR_DRBG or Hash_DRBG.