Dual_EC_DRBG is the name of a relatively new random number generator, the use of which has apparently been pushed by the NSA. However According to a recent article by By Bruce Schneier, it’s beginning to be obvious why the NSA would want to push the inclusion of this random number generator in the new encryption standard…
From the article:
This is how it works: There are a bunch of constants — fixed numbers — in the standard used to define the algorithm’s elliptic curve. These constants are listed in Appendix A of the NIST publication, but nowhere is it explained where they came from.
What Shumow and Ferguson showed is that these numbers have a relationship with a second, secret set of numbers that can act as a kind of skeleton key. If you know the secret numbers, you can predict the output of the random-number generator after collecting just 32 bytes of its output. To put that in real terms, you only need to monitor one TLS internet encryption connection in order to crack the security of that protocol. If you know the secret numbers, you can completely break any instantiation of Dual_EC_DRBG.
So it’s really obvious here, whether it’s intended that way or not (yeah, right.) this particular random number generator isn’t just weak, it should be considered broken and scrapped.