I added support of secp256k1 bitcoin stock secp256k1 curve in libgcrypt. Is there any good Bitcoin client? Where could I put my private key of Bitcoin?
M9 1a8 8 0 1 0 0 16A8 8 0 0 0 9 1zm. I am working on a bitcoin related project and I am trying to speedup the ecc calculation. I started with double-and-add and sliding window. I would like to go move over to the jacobian coordinates. I am not sure if this is correct.
Since I am not sure about this point, I started to think about the point doubling algorithm. I know that in affine coordinates this would be a problem but how does it look in Jacobian? Looks like you found those algorithms here? See the answer here for more about that. I would highly recommend getting your formulas from the Explicit-Formulas Database in the future, or at least using it as a cross-check. They do a great job sourcing where their algorithms come from. Yes, you are right about the location where I found it.
When I want to double a point, how do I check if it is the point at infinity? Would I check if X and Y are 1 and Z equals 0? I don’t have experience with Bitcoin calculations, but that’s what I would do to start. Not the answer you’re looking for?