Exemple #1
0
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
}
Exemple #2
0
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
}