Parameters

SAGE

p = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff43
K = GF(p)
a = K(0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff40)
b = K(0x25581)
E = EllipticCurve(K, (a, b))
G = E(0x01, 0x696f1853c1e466d7fc82c96cceeedd6bd02c2f9375894ec10bf46306c2b56c77)
E.set_order(0xffffffffffffffffffffffffffffffffe43c8275ea265c6020ab20294751a825 * 0x01)

PARI/GP

p = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff43
a = Mod(0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff40, p)
b = Mod(0x25581, p)
E = ellinit([a, b])
E[16][1] = 0xffffffffffffffffffffffffffffffffe43c8275ea265c6020ab20294751a825 * 0x01
G = [Mod(0x01, p), Mod(0x696f1853c1e466d7fc82c96cceeedd6bd02c2f9375894ec10bf46306c2b56c77, p)]

JSON

{
  "name": "numsp256d1",
  "desc": "",
  "form": "Weierstrass",
  "field": {
    "type": "Prime",
    "p": "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff43",
    "bits": 256
  },
  "params": {
    "a": {
      "raw": "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff40"
    },
    "b": {
      "raw": "0x25581"
    }
  },
  "generator": {
    "x": {
      "raw": "0x01"
    },
    "y": {
      "raw": "0x696f1853c1e466d7fc82c96cceeedd6bd02c2f9375894ec10bf46306c2b56c77"
    }
  },
  "order": "0xffffffffffffffffffffffffffffffffe43c8275ea265c6020ab20294751a825",
  "cofactor": "0x01"
}