What is the ECC key length for OpenCoin's implementation of Ripple?
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.