func (c *curve) initNamedCurve(name string, nid C.int) *curve {
c.name = name
c.ctx = C.BN_CTX_new()
if c.ctx == nil {
panic("C.BN_CTX_new: " + getErrString())
}
c.g = C.EC_GROUP_new_by_curve_name(nid)
if c.g == nil {
panic("can't find create P256 curve: " + getErrString())
}
// Get this curve's prime field
c.p = newBigNum()
if C.EC_GROUP_get_curve_GFp(c.g, c.p.bn, nil, nil, c.ctx) == 0 {
panic("EC_GROUP_get_curve_GFp: " + getErrString())
}
c.plen = (c.p.BitLen() + 7) / 8
// Get the curve's group order
c.n = newBigNum()
if C.EC_GROUP_get_order(c.g, c.n.bn, c.ctx) == 0 {
panic("EC_GROUP_get_order: " + getErrString())
}
c.nlen = (c.n.BitLen() + 7) / 8
// Get the curve's cofactor
c.cofact = newBigNum()
if C.EC_GROUP_get_cofactor(c.g, c.cofact.bn, c.ctx) == 0 {
panic("EC_GROUP_get_cofactor: " + getErrString())
}
// Stash a copy of the point at infinity
c.null = newPoint(c)
c.null.Null()
return c
}
func buildCurveParams(curve *C.EC_GROUP) *elliptic.CurveParams {
cp := &elliptic.CurveParams{}
// handle go < 1.5
// Name wasn't in CurveParams before
elem := reflect.ValueOf(cp).Elem()
f := elem.FieldByName("Name")
if f.IsValid() {
f.SetString(getCurveName(curve))
}
cp.BitSize = getCurveBitSize(curve)
p := C.BN_new()
if p == nil {
panic(sslerr.SSLErrorMessage().String())
}
defer C.BN_free(p)
a := C.BN_new()
if a == nil {
panic(sslerr.SSLErrorMessage().String())
}
defer C.BN_free(a)
b := C.BN_new()
if b == nil {
panic(sslerr.SSLErrorMessage().String())
}
defer C.BN_free(b)
if C.EC_GROUP_get_curve_GFp(curve, p, a, b, nil) != 1 {
panic(sslerr.SSLErrorMessage().String())
}
if p == nil || a == nil || b == nil {
panic("something went wrong getting GFp params")
}
cp.P, _ = new(big.Int).SetString(C.GoString(C.BN_bn2dec(p)), 10)
cp.N, _ = new(big.Int).SetString(C.GoString(C.BN_bn2dec(a)), 10)
cp.B, _ = new(big.Int).SetString(C.GoString(C.BN_bn2hex(b)), 16)
generator := C.EC_GROUP_get0_generator(curve)
if generator == nil {
panic("generator cannot be nil")
}
x := C.BN_new()
if x == nil {
panic(sslerr.SSLErrorMessage().String())
}
defer C.BN_free(x)
y := C.BN_new()
if y == nil {
panic(sslerr.SSLErrorMessage().String())
}
defer C.BN_free(y)
if C.EC_POINT_get_affine_coordinates_GFp(curve, generator, x, y, nil) != 1 {
panic(sslerr.SSLErrorMessage().String())
}
if x == nil || y == nil {
panic("something went wrong getting affine coordinates")
}
cp.Gx, _ = new(big.Int).SetString(C.GoString(C.BN_bn2hex(x)), 16)
cp.Gy, _ = new(big.Int).SetString(C.GoString(C.BN_bn2hex(y)), 16)
return cp
}