I'm looking at implementing elliptic curve point compression a la SEC1 (admittedly, mostly to reduce the number of "feature not supported" code paths in a library, but it seems like a somewhat useful ability). Nettle/Hogweed already implements it internally for curve25519, but I want to implement it for the "secp" curves as well.
Point compression is easy enough, but point decompression requires some curve math, potentially dependent on the specific curve, and some of it is redundant with what's already done in ecc_point_set(). So I was thinking about moving this functionality into Hogweed as a function along the lines of ecc_point_set_compressed(), which would take, instead of a y-coordinate, an int containing the sign/parity of the y-coordinate.
So my question for the list and for the maintainers is, is this a reasonable API to add to Hogweed? Is there interest in including it in Hogweed if I were to take the time to turn it into a tidy patch?