If anyone has any test problems I can run for point multiplication on the secp256k1 curve that would be great.  I think I have the implementation down, but the fact that everything is in hex is giving me fits.  I would love to be able to verify that the point multiplication works in decimal before moving on the tackling hex.

Doing the math by hand, I know that 2 * (4, 3) = (56, -419).
But doing large multiplications by hand is impossible.
For example, 100 * (4, 3) =

And for actually doing the point multiplication required by bitcoin...

Let's say privatekey (in hex) = 059E2BF5E2C7A4098C164B29A91CF70508D2FD1A256A60656FD2593BDB980FAA
so privatekey in dec = 2541029483313867478679144795827841690699430215057902992954466247848698056618
Gx (in hex) = 79BE667E F9DCBBAC 55A06295 CE870B07 029BFCDB 2DCE28D9 59F2815B 16F81798
so Gx in dec = 55066263022277343669578718895168534326250603453777594175500187360389116729240
Gy (in hex) = 483ADA77 26A3C465 5DA4FBFC 0E1108A8 FD17B448 A6855419 9C47D08F FB10D4B8
so Gy in dec = 32670510020758816978083085130507043184471273380659243275938904335757337482424

so, given that privatekey * (Gx, Gy) = publickey
the math is (in dec): 2541029483313867478679144795827841690699430215057902992954466247848698056618 * (55066263022277343669578718895168534326250603453777594175500187360389116729240, 32670510020758816978083085130507043184471273380659243275938904335757337482424).

Having a real hard time seeing if my function works with numbers that big...