Today, the New York Times reported that an algorithm for generating random numbers, which was adopted in 2006 by the National Institute of Standards and Technology (NIST), contains a backdoor for the NSA.

The news followed a NYT report from last week, which indicated that the National Security Agency (NSA) had circumvented widely used (but then-unnamed) encryption schemes by placing backdoors in the standards that are used to implement the encryption. In 2007, cryptographers Niels Ferguson and Dan Shumow presented research suggesting that there could be a potential backdoor in the Dual_EC_DRBG algorithm, which NIST had included in Special Publication 800-90.

If the parameters used to define the algorithm were chosen in a particular way, they would allow the NSA to predict the supposedly random numbers produced by the algorithm. It wasn’t entirely clear at the time that the NSA had picked the parameters in this way; as Ars noted last week, the rationale for choosing the particular Dual_EC_DRBG parameters in SP 800-90 was never actually stated. Today, the NYT says that internal memos leaked by Edward Snowden confirm that the NSA generated the Dual_EC_DRBG algorithm. Publicly, however, the agency’s role in development was significantly underbilled: “In publishing the standard, NIST acknowledged ‘contributions’ from NSA, but not primary authorship,” wrote the NYT. From there, the NSA pushed the International Organization for Standardization to adopt the algorithm, calling it “a challenge in finesse” to convince the organization’s leadership.     

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