What is the ECC key length for OpenCoin's implementation of Ripple? http://www.reddit.com/r/Bitcoin/comments/1lubl1/wired_oped_worries_that_elliptic_curve/cc2vhos suggests that key lengths &lt; 500 bits are no longer considered secure from the NSA.  What key length is Ripple using?
Ripple uses the same signature scheme as Bitcoin, 256-bit ECDSA keys and elliptic curve SECP256k1. It takes about 5 times more CPU effort to verify a 512-bit ECDSA signature than a 256-bit ECDSA signature and signature verification is a huge CPU load for both Bitcoin and Ripple. And, of course, keys and signatures are twice as long.