IN THROUGH THE BACKDOOR —

Report: RSA endowed crypto product with second NSA-influenced code

Extended Random like "dousing yourself with gasoline," professor warns.

Security provider RSA endowed its BSAFE cryptography toolkit with a second NSA-influenced random number generator (RNG) that's so weak it makes it easier for eavesdroppers to decrypt protected communications, Reuters reported Monday.

Citing soon-to-be-published research from several universities, Reuters said the Extended Random extension for secure websites allows attackers to work tens of thousands of times faster when breaking cryptography that uses the Dual EC_DRBG algorithm to generate the random numbers that populate a specific cryptographic key. Dual EC_DRBG is a pseudo-random number generator that was developed by cryptographers from the National Security Agency and was the default RNG in BSAFE even after researchers demonstrated weaknesses so severe that many suspected they were introduced intentionally so the US spy agency could exploit them to crack encrypted communications of people it wanted to monitor. In December, Reuters reported that the NSA paid RSA $10 million to give Dual EC_DRBG its favored position in BSAFE.

Extended Random was a second RNG that would presumably make cryptographic keys more robust by adding a second source of randomness. In theory, the additional RNG should increase the entropy used when constructing a new key. In reality, the algorithm made protected communications even easier for attackers to decrypt by reducing the time it takes to predict the random numbers generated by Dual EC_DRBG, which is short for Dual Elliptic Curve, Reuters reported Monday.

"If using Dual Elliptic Curve is like playing with matches, then adding Extended Random is like dousing yourself with gasoline," Matt Green, a professor specializing in cryptography at Johns Hopkins University and one of the authors of the upcoming academic report, told Reuters. Monday's report continued:

The NSA played a significant role in the origins of Extended Random. The authors of the 2008 paper on the protocol were Margaret Salter, technical director of the NSA's defensive Information Assurance Directorate, and an outside expert named Eric Rescorla.

Rescorla, who has advocated greater encryption of all Web traffic, works for Mozilla, maker of the Firefox Web browser. He and Mozilla declined to comment. Salter did not respond to requests for comment.

Though few companies appear to have embraced Extended Random, RSA did. The company built in support for the protocol in BSafe toolkit versions for the Java programming language about five years ago, when a preeminent Internet standards group—the Internet Engineering Task Force—was considering whether to adopt Extended Random as an industry standard. The IETF decided in the end not to adopt the protocol.

The researchers said it took them about an hour to crack a free version of BSAFE for Java using about $40,000 worth of computer gear, Reuters reported. Cracking was 65,000 times faster when BSAFE used Extended Random, an improvement that reduced attacks to seconds.

Channel Ars Technica