Jon Callas <jon(_at_)callas(_dot_)org>:
[...]
ECC does *not* affect the speed of large file encryption. Actually, it's
the opposite; it matters most for *small* files.
You cannot expect elliptic curve based encryption to be faster than
RSA encryption. Signing and decryption may be faster than for RSA or
DSA/ElGamal (but not necessarily when the platform is a PC or
workstations and if the modular exponentiation implementation is
reasonably well optimized), but it is hard to beat RSA public key
operations with small exponents.