Following the recent reports about the NSA weakening this standard, the NIST reopened Special Publication 800-90A, which includes the Dual_EC_DRBG specification, for public comments. The organization also denied that it would deliberately weaken a cryptographic standard.
However, the harm to the NIST's reputation seems already to have been done.
RSA, the security division of EMC, has since advised customers that its BSAFE cryptographic libraries and its Data Protection Manager products have been using Dual_EC_DRBG by default and strongly recommended that they switch to a different PRNG using instructions in the product documentation.
Silent Circle's new decision to move away from AES, SHA-2 and the P-384 curve doesn't mean that these standards are insecure, Callas said in the blog post. "It doesn't mean we think less of our friends at NIST, whom we have the utmost respect for; they are victims of the NSA's perfidy, along with the rest of the free world. For us, the spell is broken. We're just moving on."
The company still plans to support the NIST-sanctioned algorithms in its services, but they won't be the default choice anymore.
Asked why Twofish and Skein in particular were chosen to be the new default choices for Silent Circle's products, Callas said via email that both algorithms come from trusted sources, including himself in the case of Skein.
Twofish was a finalist in the NIST's selection of the AES cipher, and the team that developed it included people that Silent Circle's co-founders personally know and trust, he said. "A number of the same people produced Skein -- which was a SHA-3 finalist -- and I am a member of the Skein team."
For Silent Circle this was a "decision of conscience," Callas said. "Our primary responsibility is to protect our customers, especially in the face of uncertainty."
However, Callas doesn't think other vendors necessarily should follow suit and move away from NIST cryptographic standards.
"I wouldn't fault anyone for deciding differently," he said. "We need more of the world coming together with security and respecting each other's decisions even if we make different decisions and do different things. If someone decides to stay the course, I respect that."
"That's also why we're going to allow customers to use the old algorithms," Callas said. "We respect their personal decisions, too."