x448: Export shared secret size (#3)

Changes x448Bytes variable to SharedSecretSize

ec/x448/x448.go

@@ -28,7 +28,7 @@
 package x448
 
 const (
-	x448Bytes = 56
+	SharedSecretSize = 56
 	edwardsD         = -39081
 )
 
@@ -55,7 +55,7 @@ func ScalarMult(out, scalar, base *[56]byte) int {
 		// Scalar conditioning.
 		if t/8 == 0 {
 			sb &= 0xFC
-		} else if t/8 == x448Bytes-1 {
+		} else if t/8 == SharedSecretSize-1 {
 			sb |= 0x80
 		}
 

ec/x448/x448_ref.go

@@ -742,14 +742,14 @@ func (a *gf) canon() {
 }
 
 // deser deserializes into the limb representation.
-func (s *gf) deser(ser *[x448Bytes]byte) {
+func (s *gf) deser(ser *[SharedSecretSize]byte) {
 	var buf uint64
 	bits := uint(0)
 	k := 0
 
 	for i, v := range ser {
 		buf |= (uint64)(v) << bits
-		for bits += 8; (bits >= lBits || i == x448Bytes-1) && k < x448Limbs; bits, buf = bits-lBits, buf>>lBits {
+		for bits += 8; (bits >= lBits || i == SharedSecretSize-1) && k < x448Limbs; bits, buf = bits-lBits, buf>>lBits {
 			s.limb[k] = (uint32)(buf & lMask)
 			k++
 		}
@@ -757,14 +757,14 @@ func (s *gf) deser(ser *[x448Bytes]byte) {
 }
 
 // ser serializes into byte representation.
-func (a *gf) ser(ser *[x448Bytes]byte) {
+func (a *gf) ser(ser *[SharedSecretSize]byte) {
 	a.canon()
 	k := 0
 	bits := uint(0)
 	var buf uint64
 	for i, v := range a.limb {
 		buf |= (uint64)(v) << bits
-		for bits += lBits; (bits >= 8 || i == x448Limbs-1) && k < x448Bytes; bits, buf = bits-8, buf>>8 {
+		for bits += lBits; (bits >= 8 || i == x448Limbs-1) && k < SharedSecretSize; bits, buf = bits-8, buf>>8 {
 			ser[k] = (byte)(buf)
 			k++
 		}

ec/x448/x448_test.go

@@ -38,14 +38,14 @@ var reallyRunSlowTest = false
 
 func TestX448(t *testing.T) {
 	type KATVectors struct {
-		scalar [x448Bytes]byte
-		base   [x448Bytes]byte
-		answer [x448Bytes]byte
+		scalar [SharedSecretSize]byte
+		base   [SharedSecretSize]byte
+		answer [SharedSecretSize]byte
 	}
 
 	vectors := []KATVectors{
 		{
-			[x448Bytes]byte{
+			[SharedSecretSize]byte{
 				0x3d, 0x26, 0x2f, 0xdd, 0xf9, 0xec, 0x8e, 0x88,
 				0x49, 0x52, 0x66, 0xfe, 0xa1, 0x9a, 0x34, 0xd2,
 				0x88, 0x82, 0xac, 0xef, 0x04, 0x51, 0x04, 0xd0,
@@ -54,7 +54,7 @@ func TestX448(t *testing.T) {
 				0xf4, 0x49, 0x43, 0xeb, 0xa3, 0x68, 0xf5, 0x4b,
 				0x29, 0x25, 0x9a, 0x4f, 0x1c, 0x60, 0x0a, 0xd3,
 			},
-			[x448Bytes]byte{
+			[SharedSecretSize]byte{
 				0x06, 0xfc, 0xe6, 0x40, 0xfa, 0x34, 0x87, 0xbf,
 				0xda, 0x5f, 0x6c, 0xf2, 0xd5, 0x26, 0x3f, 0x8a,
 				0xad, 0x88, 0x33, 0x4c, 0xbd, 0x07, 0x43, 0x7f,
@@ -63,7 +63,7 @@ func TestX448(t *testing.T) {
 				0x83, 0xfa, 0x54, 0x29, 0xdb, 0x94, 0xad, 0xa1,
 				0x8a, 0xa7, 0xa7, 0xfb, 0x4e, 0xf8, 0xa0, 0x86,
 			},
-			[x448Bytes]byte{
+			[SharedSecretSize]byte{
 				0xce, 0x3e, 0x4f, 0xf9, 0x5a, 0x60, 0xdc, 0x66,
 				0x97, 0xda, 0x1d, 0xb1, 0xd8, 0x5e, 0x6a, 0xfb,
 				0xdf, 0x79, 0xb5, 0x0a, 0x24, 0x12, 0xd7, 0x54,
@@ -74,7 +74,7 @@ func TestX448(t *testing.T) {
 			},
 		},
 		{
-			[x448Bytes]byte{
+			[SharedSecretSize]byte{
 				0x20, 0x3d, 0x49, 0x44, 0x28, 0xb8, 0x39, 0x93,
 				0x52, 0x66, 0x5d, 0xdc, 0xa4, 0x2f, 0x9d, 0xe8,
 				0xfe, 0xf6, 0x00, 0x90, 0x8e, 0x0d, 0x46, 0x1c,
@@ -83,7 +83,7 @@ func TestX448(t *testing.T) {
 				0x31, 0x5c, 0x44, 0xe0, 0xa5, 0xb4, 0x37, 0x12,
 				0x82, 0xdd, 0x2c, 0x8d, 0x5b, 0xe3, 0x09, 0x5f,
 			},
-			[x448Bytes]byte{
+			[SharedSecretSize]byte{
 				0x0f, 0xbc, 0xc2, 0xf9, 0x93, 0xcd, 0x56, 0xd3,
 				0x30, 0x5b, 0x0b, 0x7d, 0x9e, 0x55, 0xd4, 0xc1,
 				0xa8, 0xfb, 0x5d, 0xbb, 0x52, 0xf8, 0xe9, 0xa1,
@@ -92,7 +92,7 @@ func TestX448(t *testing.T) {
 				0x2f, 0xe2, 0x05, 0xe2, 0x8a, 0x78, 0xb9, 0x1c,
 				0xdf, 0xbd, 0xe7, 0x1c, 0xe8, 0xd1, 0x57, 0xdb,
 			},
-			[x448Bytes]byte{
+			[SharedSecretSize]byte{
 				0x88, 0x4a, 0x02, 0x57, 0x62, 0x39, 0xff, 0x7a,
 				0x2f, 0x2f, 0x63, 0xb2, 0xdb, 0x6a, 0x9f, 0xf3,
 				0x70, 0x47, 0xac, 0x13, 0x56, 0x8e, 0x1e, 0x30,
@@ -104,7 +104,7 @@ func TestX448(t *testing.T) {
 		},
 	}
 
-	var out [x448Bytes]byte
+	var out [SharedSecretSize]byte
 	for i, vec := range vectors {
 		ret := ScalarMult(&out, &vec.scalar, &vec.base)
 		if ret != 0 {
@@ -126,7 +126,7 @@ func TestX448IETFDraft(t *testing.T) {
 	// refuse to run the full 1 million iterations, and the `go test`
 	// timeout will need to be increased (`go test -timeout 30m`).
 
-	var k, u, out [x448Bytes]byte
+	var k, u, out [SharedSecretSize]byte
 	copy(k[:], basePoint[:])
 	copy(u[:], basePoint[:])
 
@@ -160,7 +160,7 @@ func TestX448IETFDraft(t *testing.T) {
 }
 
 func TestCurve448(t *testing.T) {
-	alicePriv := [x448Bytes]byte{
+	alicePriv := [SharedSecretSize]byte{
 		0x9a, 0x8f, 0x49, 0x25, 0xd1, 0x51, 0x9f, 0x57,
 		0x75, 0xcf, 0x46, 0xb0, 0x4b, 0x58, 0x00, 0xd4,
 		0xee, 0x9e, 0xe8, 0xba, 0xe8, 0xbc, 0x55, 0x65,
@@ -170,7 +170,7 @@ func TestCurve448(t *testing.T) {
 		0x9a, 0xc2, 0xd8, 0xc0, 0xa5, 0x98, 0x72, 0x6b,
 	}
 
-	alicePub := [x448Bytes]byte{
+	alicePub := [SharedSecretSize]byte{
 		0x9b, 0x08, 0xf7, 0xcc, 0x31, 0xb7, 0xe3, 0xe6,
 		0x7d, 0x22, 0xd5, 0xae, 0xa1, 0x21, 0x07, 0x4a,
 		0x27, 0x3b, 0xd2, 0xb8, 0x3d, 0xe0, 0x9c, 0x63,
@@ -180,7 +180,7 @@ func TestCurve448(t *testing.T) {
 		0x17, 0x7f, 0x80, 0xe5, 0x32, 0xc4, 0x1f, 0xa0,
 	}
 
-	bobPriv := [x448Bytes]byte{
+	bobPriv := [SharedSecretSize]byte{
 		0x1c, 0x30, 0x6a, 0x7a, 0xc2, 0xa0, 0xe2, 0xe0,
 		0x99, 0x0b, 0x29, 0x44, 0x70, 0xcb, 0xa3, 0x39,
 		0xe6, 0x45, 0x37, 0x72, 0xb0, 0x75, 0x81, 0x1d,
@@ -190,7 +190,7 @@ func TestCurve448(t *testing.T) {
 		0x36, 0x6f, 0x10, 0xb6, 0x51, 0x73, 0x99, 0x2d,
 	}
 
-	bobPub := [x448Bytes]byte{
+	bobPub := [SharedSecretSize]byte{
 		0x3e, 0xb7, 0xa8, 0x29, 0xb0, 0xcd, 0x20, 0xf5,
 		0xbc, 0xfc, 0x0b, 0x59, 0x9b, 0x6f, 0xec, 0xcf,
 		0x6d, 0xa4, 0x62, 0x71, 0x07, 0xbd, 0xb0, 0xd4,
@@ -200,7 +200,7 @@ func TestCurve448(t *testing.T) {
 		0x07, 0xbd, 0xc1, 0xc6, 0x7b, 0xf3, 0x36, 0x09,
 	}
 
-	aliceBob := [x448Bytes]byte{
+	aliceBob := [SharedSecretSize]byte{
 		0x07, 0xff, 0xf4, 0x18, 0x1a, 0xc6, 0xcc, 0x95,
 		0xec, 0x1c, 0x16, 0xa9, 0x4a, 0x0f, 0x74, 0xd1,
 		0x2d, 0xa2, 0x32, 0xce, 0x40, 0xa7, 0x75, 0x52,
@@ -210,7 +210,7 @@ func TestCurve448(t *testing.T) {
 		0x44, 0x9a, 0x50, 0x37, 0x51, 0x4a, 0x87, 0x9d,
 	}
 
-	var out [x448Bytes]byte
+	var out [SharedSecretSize]byte
 	ret := ScalarBaseMult(&out, &alicePriv)
 	if ret != 0 {
 		t.Error("Alice: ScalarBaseMult failed")
@@ -242,7 +242,7 @@ func TestCurve448(t *testing.T) {
 }
 
 func BenchmarkECDH(b *testing.B) {
-	var sa, sb, pa, pb, ab, ba [x448Bytes]byte
+	var sa, sb, pa, pb, ab, ba [SharedSecretSize]byte
 	ret := 0
 
 	rand.Read(sa[:])