By Vipul Gupta on Dec 01, 2009
One of my previous blog posts talked about Elliptic Curve Cryptography, why it is being endorsed by the National Security Agency and how a small team of researchers at Sun Labs has had a big hand in promoting its wide-spread industry adoption.
A few days ago, I received notification that the development team behind Apache has finally integrated the patch that makes this next-generation security technology available to the users and administrators of the world's most popular web server. It has been a long, slow journey -- we demonstrated the first version of ECC-enabled Apache at a Sun Labs Open House in 2004 (and you thought high tech moves fast!) -- but I'm excited to see this final chip fall in place. It is a significant milestone in overhauling the cryptographic underpinnings of the World Wide Web.
The timing couldn't be better. NIST guidelines (see pages 63, 66) recommend that key sizes used with RSA (the currently popular incumbent technology) be doubled from 1024- to 2048-bits after 2010 to guarantee adequate protection of sensitive information -- think online banking and e-commerce. The big advantage of ECC is it can provide equivalent security using much smaller keys. More specifically, corresponding ECC key sizes only need to increase from 160- to 224-bits. Since the computational cost of public-key operations grows roughly as the cube of the key-size, the performance advantage of ECC over RSA increases as security needs increase over time:
Table 1 compares the speed of doing an RSA decryption against the speed of an ECDH computation. These are the main cryptographic operations a web server needs to perform for establishing an HTTPS connection. As shown, ECC operations are faster by a factor of more than six for key sizes needed beyond 2010. I wouldn't expect an ECC-based HTTPS server to perform six times better than an RSA-based server because there are other operations in processing an HTTPS request that are common to both. One needs HTTPS-level testing with a tool like httpperf to determine the actual speedup. We did such a study back in 2004 and found that an ECC-based HTTPS server can handle between two to four times as many connections as an RSA-based server (for key sizes needed beyond 2010). I'd love to repeat that experiment with the latest software running on contemporary hardware when I can find some time. Stay tuned.
- "More times than we can count, we've made history, without history even knowing we were there."
- Keith Alexander, Director NSA/Chief CSS, speaking at the NSA's 55th Anniversary.
(For many years, the U.S. government did not acknowledge the existence of the
NSA earning it the nickname "No Such Agency")