"errors"
	"sync"
)

// p256ElementLength is the length of an element of the base or scalar field,
// which have the same bytes length for all NIST P curves.
const p256ElementLength = 32

// P256Point is a P256 point. The zero value is NOT valid.
type P256Point struct {
	// The point is represented in projective coordinates (X:Y:Z),
	// where x = X/Z and y = Y/Z.
	x, y, z *fiat.P256Element
}

	})
	return _p224
}

var p256Once sync.Once
var _p256 *nistCurve[*nistec.P256Point]

func p256() *nistCurve[*nistec.P256Point] {
	p256Once.Do(func() {
		_p256 = &nistCurve[*nistec.P256Point]{
			newPoint: func() *nistec.P256Point { return nistec.NewP256Point() },
		}
		precomputeParams(_p256, elliptic.P256())
	})
	return _p256
}

var p384Once sync.Once
var _p384 *nistCurve[*nistec.P384Point]

//go:build (amd64 || arm64) && !purego

package nistec_test

import (
	"bytes"
	"crypto/elliptic"
	"crypto/internal/nistec"
	"math/big"
	"testing"
)

func TestP256OrdInverse(t *testing.T) {
	N := elliptic.P256().Params().N

	// inv(0) is expected to be 0.
	zero := make([]byte, 32)
	out, err := nistec.P256OrdInverse(zero)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(out, zero) {

DATA p256ord<>+0x18(SB)/8, $0xf3b9cac2fc632551
DATA p256<>+0x00(SB)/8, $0xffffffff00000001 // P256
DATA p256<>+0x08(SB)/8, $0x0000000000000000 // P256
DATA p256<>+0x10(SB)/8, $0x00000000ffffffff // P256
DATA p256<>+0x18(SB)/8, $0xffffffffffffffff // P256
DATA p256<>+0x20(SB)/8, $0x0c0d0e0f1c1d1e1f // SEL d1 d0 d1 d0
DATA p256<>+0x28(SB)/8, $0x0c0d0e0f1c1d1e1f // SEL d1 d0 d1 d0
DATA p256<>+0x30(SB)/8, $0x0000000010111213 // SEL 0  d1 d0  0

// on little endian.
DATA p256<>+0x00(SB)/8, $0xffffffff00000001 // P256
DATA p256<>+0x08(SB)/8, $0x0000000000000000 // P256
DATA p256<>+0x10(SB)/8, $0x00000000ffffffff // P256
DATA p256<>+0x18(SB)/8, $0xffffffffffffffff // P256
DATA p256<>+0x20(SB)/8, $0x0c0d0e0f1c1d1e1f // SEL d1 d0 d1 d0
DATA p256<>+0x28(SB)/8, $0x0c0d0e0f1c1d1e1f // SEL d1 d0 d1 d0
DATA p256<>+0x30(SB)/8, $0x0000000010111213 // SEL 0  d1 d0  0

Roland Shoemaker <******@****.***> 1715710936 -0700

Roland Shoemaker <******@****.***> 1715710936 -0700

func testAllCurves(t *testing.T, f func(*testing.T, elliptic.Curve)) {
	tests := []struct {
		name  string
		curve elliptic.Curve
	}{
		{"P256", elliptic.P256()},
		{"P224", elliptic.P224()},
		{"P384", elliptic.P384()},
		{"P521", elliptic.P521()},
		{"P256/Generic", genericParamsForCurve(elliptic.P256())},
	}
	if testing.Short() {
		tests = tests[:1]
	}
	for _, test := range tests {
		curve := test.curve

				t.Errorf("boringcrypto error leaked out: %v", err)
			}
		}
	})
}

func testAllCurves(t *testing.T, f func(t *testing.T, curve ecdh.Curve)) {
	t.Run("P256", func(t *testing.T) { f(t, ecdh.P256()) })
	t.Run("P384", func(t *testing.T) { f(t, ecdh.P384()) })
	t.Run("P521", func(t *testing.T) { f(t, ecdh.P521()) })
	t.Run("X25519", func(t *testing.T) { f(t, ecdh.X25519()) })
}

// a generic, non-constant time implementation of [Curve].
//
// The generic Curve implementation is deprecated, and using custom curves
// (those not returned by [P224], [P256], [P384], and [P521]) is not guaranteed
// to provide any security property.
type CurveParams struct {
	P       *big.Int // the order of the underlying field
	N       *big.Int // the order of the base point