sha3: simplify XOR functions

name old time/op new time/op delta PermutationFunction-4 398ns ± 0% 399ns ± 1% ~ (p=0.508 n=9+10) Sha3_512_MTU-4 8.34µs ± 1% 8.36µs ± 1% ~ (p=0.101 n=10+10) Sha3_384_MTU-4 6.00µs ± 0% 6.02µs ± 1% +0.47% (p=0.000 n=8+10) Sha3_256_MTU-4 4.78µs ± 0% 4.79µs ± 1% ~ (p=0.324 n=10+10) Sha3_224_MTU-4 4.57µs ± 1% 4.57µs ± 1% ~ (p=0.288 n=10+10) Shake128_MTU-4 3.87µs ± 0% 3.86µs ± 1% -0.22% (p=0.008 n=9+9) Shake256_MTU-4 4.17µs ± 0% 4.17µs ± 0% ~ (p=0.474 n=10+8) Shake256_16x-4 59.4µs ± 0% 59.7µs ± 0% +0.48% (p=0.000 n=9+8) Shake256_1MiB-4 3.19ms ± 1% 3.20ms ± 0% ~ (p=0.105 n=10+10) Sha3_512_1MiB-4 5.97ms ± 0% 6.01ms ± 0% +0.75% (p=0.000 n=10+10) name old speed new speed delta PermutationFunction-4 502MB/s ± 0% 502MB/s ± 0% ~ (p=0.497 n=9+10) Sha3_512_MTU-4 162MB/s ± 1% 161MB/s ± 1% ~ (p=0.101 n=10+10) Sha3_384_MTU-4 225MB/s ± 0% 224MB/s ± 1% -0.47% (p=0.000 n=8+10) Sha3_256_MTU-4 282MB/s ± 0% 282MB/s ± 1% ~ (p=0.325 n=10+10) Sha3_224_MTU-4 296MB/s ± 1% 295MB/s ± 1% ~ (p=0.280 n=10+10) Shake128_MTU-4 349MB/s ± 0% 350MB/s ± 1% +0.22% (p=0.008 n=9+9) Shake256_MTU-4 324MB/s ± 0% 324MB/s ± 0% ~ (p=0.459 n=10+8) Shake256_16x-4 276MB/s ± 0% 274MB/s ± 0% -0.48% (p=0.000 n=9+8) Shake256_1MiB-4 328MB/s ± 1% 327MB/s ± 0% ~ (p=0.105 n=10+10) Sha3_512_1MiB-4 176MB/s ± 0% 174MB/s ± 0% -0.74% (p=0.000 n=10+10) Change-Id: Ib8e571f3c9a0f84096df2f38ca96da197ad5be30 Reviewed-on: https://go-review.googlesource.com/c/crypto/+/544815 Auto-Submit: Filippo Valsorda <filippo@golang.org> Reviewed-by: Roland Shoemaker <roland@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
2024-05-06 15:29:57 +00:00
parent 905d78a692
commit 10f366e7a2
5 changed files with 180 additions and 278 deletions
@@ -40,7 +40,7 @@ type state struct {
 	//      Extendable-Output Functions (May 2014)"
 	dsbyte byte

-	storage storageBuf
+	storage [maxRate]byte

 	// Specific to SHA-3 and SHAKE.
 	outputLen int             // the default output size in bytes
@@ -61,15 +61,15 @@ func (d *state) Reset() {
 		d.a[i] = 0
 	}
 	d.state = spongeAbsorbing
-	d.buf = d.storage.asBytes()[:0]
+	d.buf = d.storage[:0]
 }

 func (d *state) clone() *state {
 	ret := *d
 	if ret.state == spongeAbsorbing {
-		ret.buf = ret.storage.asBytes()[:len(ret.buf)]
+		ret.buf = ret.storage[:len(ret.buf)]
 	} else {
-		ret.buf = ret.storage.asBytes()[d.rate-cap(d.buf) : d.rate]
+		ret.buf = ret.storage[d.rate-cap(d.buf) : d.rate]
 	}

 	return &ret
@@ -83,13 +83,13 @@ func (d *state) permute() {
 		// If we're absorbing, we need to xor the input into the state
 		// before applying the permutation.
 		xorIn(d, d.buf)
-		d.buf = d.storage.asBytes()[:0]
+		d.buf = d.storage[:0]
 		keccakF1600(&d.a)
 	case spongeSqueezing:
 		// If we're squeezing, we need to apply the permutation before
 		// copying more output.
 		keccakF1600(&d.a)
-		d.buf = d.storage.asBytes()[:d.rate]
+		d.buf = d.storage[:d.rate]
 		copyOut(d, d.buf)
 	}
 }
@@ -98,7 +98,7 @@ func (d *state) permute() {
 // the multi-bitrate 10..1 padding rule, and permutes the state.
 func (d *state) padAndPermute(dsbyte byte) {
 	if d.buf == nil {
-		d.buf = d.storage.asBytes()[:0]
+		d.buf = d.storage[:0]
 	}
 	// Pad with this instance's domain-separator bits. We know that there's
 	// at least one byte of space in d.buf because, if it were full,
@@ -106,7 +106,7 @@ func (d *state) padAndPermute(dsbyte byte) {
 	// first one bit for the padding. See the comment in the state struct.
 	d.buf = append(d.buf, dsbyte)
 	zerosStart := len(d.buf)
-	d.buf = d.storage.asBytes()[:d.rate]
+	d.buf = d.storage[:d.rate]
 	for i := zerosStart; i < d.rate; i++ {
 		d.buf[i] = 0
 	}
@@ -117,7 +117,7 @@ func (d *state) padAndPermute(dsbyte byte) {
 	// Apply the permutation
 	d.permute()
 	d.state = spongeSqueezing
-	d.buf = d.storage.asBytes()[:d.rate]
+	d.buf = d.storage[:d.rate]
 	copyOut(d, d.buf)
 }

@@ -128,7 +128,7 @@ func (d *state) Write(p []byte) (written int, err error) {
 		panic("sha3: Write after Read")
 	}
 	if d.buf == nil {
-		d.buf = d.storage.asBytes()[:0]
+		d.buf = d.storage[:0]
 	}
 	written = len(p)

@@ -76,86 +76,73 @@ type KeccakKats struct {
 	}
 }

-func testUnalignedAndGeneric(t *testing.T, testf func(impl string)) {
-	xorInOrig, copyOutOrig := xorIn, copyOut
-	xorIn, copyOut = xorInGeneric, copyOutGeneric
-	testf("generic")
-	if xorImplementationUnaligned != "generic" {
-		xorIn, copyOut = xorInUnaligned, copyOutUnaligned
-		testf("unaligned")
-	}
-	xorIn, copyOut = xorInOrig, copyOutOrig
-}
-
 // TestKeccakKats tests the SHA-3 and Shake implementations against all the
 // ShortMsgKATs from https://github.com/gvanas/KeccakCodePackage
 // (The testvectors are stored in keccakKats.json.deflate due to their length.)
 func TestKeccakKats(t *testing.T) {
-	testUnalignedAndGeneric(t, func(impl string) {
-		// Read the KATs.
-		deflated, err := os.Open(katFilename)
-		if err != nil {
-			t.Errorf("error opening %s: %s", katFilename, err)
-		}
-		file := flate.NewReader(deflated)
-		dec := json.NewDecoder(file)
-		var katSet KeccakKats
-		err = dec.Decode(&katSet)
-		if err != nil {
-			t.Errorf("error decoding KATs: %s", err)
-		}
+	// Read the KATs.
+	deflated, err := os.Open(katFilename)
+	if err != nil {
+		t.Errorf("error opening %s: %s", katFilename, err)
+	}
+	file := flate.NewReader(deflated)
+	dec := json.NewDecoder(file)
+	var katSet KeccakKats
+	err = dec.Decode(&katSet)
+	if err != nil {
+		t.Errorf("error decoding KATs: %s", err)
+	}

-		for algo, function := range testDigests {
-			d := function()
-			for _, kat := range katSet.Kats[algo] {
-				d.Reset()
-				in, err := hex.DecodeString(kat.Message)
-				if err != nil {
-					t.Errorf("error decoding KAT: %s", err)
-				}
-				d.Write(in[:kat.Length/8])
-				got := strings.ToUpper(hex.EncodeToString(d.Sum(nil)))
-				if got != kat.Digest {
-					t.Errorf("function=%s, implementation=%s, length=%d\nmessage:\n %s\ngot:\n  %s\nwanted:\n %s",
-						algo, impl, kat.Length, kat.Message, got, kat.Digest)
-					t.Logf("wanted %+v", kat)
-					t.FailNow()
-				}
-				continue
+	for algo, function := range testDigests {
+		d := function()
+		for _, kat := range katSet.Kats[algo] {
+			d.Reset()
+			in, err := hex.DecodeString(kat.Message)
+			if err != nil {
+				t.Errorf("error decoding KAT: %s", err)
 			}
-		}
-
-		for algo, v := range testShakes {
-			for _, kat := range katSet.Kats[algo] {
-				N, err := hex.DecodeString(kat.N)
-				if err != nil {
-					t.Errorf("error decoding KAT: %s", err)
-				}
-
-				S, err := hex.DecodeString(kat.S)
-				if err != nil {
-					t.Errorf("error decoding KAT: %s", err)
-				}
-				d := v.constructor(N, S)
-				in, err := hex.DecodeString(kat.Message)
-				if err != nil {
-					t.Errorf("error decoding KAT: %s", err)
-				}
-
-				d.Write(in[:kat.Length/8])
-				out := make([]byte, len(kat.Digest)/2)
-				d.Read(out)
-				got := strings.ToUpper(hex.EncodeToString(out))
-				if got != kat.Digest {
-					t.Errorf("function=%s, implementation=%s, length=%d N:%s\n S:%s\nmessage:\n %s \ngot:\n  %s\nwanted:\n %s",
-						algo, impl, kat.Length, kat.N, kat.S, kat.Message, got, kat.Digest)
-					t.Logf("wanted %+v", kat)
-					t.FailNow()
-				}
-				continue
+			d.Write(in[:kat.Length/8])
+			got := strings.ToUpper(hex.EncodeToString(d.Sum(nil)))
+			if got != kat.Digest {
+				t.Errorf("function=%s, length=%d\nmessage:\n %s\ngot:\n  %s\nwanted:\n %s",
+					algo, kat.Length, kat.Message, got, kat.Digest)
+				t.Logf("wanted %+v", kat)
+				t.FailNow()
 			}
+			continue
 		}
-	})
+	}
+
+	for algo, v := range testShakes {
+		for _, kat := range katSet.Kats[algo] {
+			N, err := hex.DecodeString(kat.N)
+			if err != nil {
+				t.Errorf("error decoding KAT: %s", err)
+			}
+
+			S, err := hex.DecodeString(kat.S)
+			if err != nil {
+				t.Errorf("error decoding KAT: %s", err)
+			}
+			d := v.constructor(N, S)
+			in, err := hex.DecodeString(kat.Message)
+			if err != nil {
+				t.Errorf("error decoding KAT: %s", err)
+			}
+
+			d.Write(in[:kat.Length/8])
+			out := make([]byte, len(kat.Digest)/2)
+			d.Read(out)
+			got := strings.ToUpper(hex.EncodeToString(out))
+			if got != kat.Digest {
+				t.Errorf("function=%s, length=%d N:%s\n S:%s\nmessage:\n %s \ngot:\n  %s\nwanted:\n %s",
+					algo, kat.Length, kat.N, kat.S, kat.Message, got, kat.Digest)
+				t.Logf("wanted %+v", kat)
+				t.FailNow()
+			}
+			continue
+		}
+	}
 }

 // TestKeccak does a basic test of the non-standardized Keccak hash functions.
@@ -219,119 +206,111 @@ func TestShakeSum(t *testing.T) {
 // TestUnalignedWrite tests that writing data in an arbitrary pattern with
 // small input buffers.
 func TestUnalignedWrite(t *testing.T) {
-	testUnalignedAndGeneric(t, func(impl string) {
-		buf := sequentialBytes(0x10000)
-		for alg, df := range testDigests {
-			d := df()
-			d.Reset()
-			d.Write(buf)
-			want := d.Sum(nil)
-			d.Reset()
-			for i := 0; i < len(buf); {
-				// Cycle through offsets which make a 137 byte sequence.
-				// Because 137 is prime this sequence should exercise all corner cases.
-				offsets := [17]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 1}
-				for _, j := range offsets {
-					if v := len(buf) - i; v < j {
-						j = v
-					}
-					d.Write(buf[i : i+j])
-					i += j
+	buf := sequentialBytes(0x10000)
+	for alg, df := range testDigests {
+		d := df()
+		d.Reset()
+		d.Write(buf)
+		want := d.Sum(nil)
+		d.Reset()
+		for i := 0; i < len(buf); {
+			// Cycle through offsets which make a 137 byte sequence.
+			// Because 137 is prime this sequence should exercise all corner cases.
+			offsets := [17]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 1}
+			for _, j := range offsets {
+				if v := len(buf) - i; v < j {
+					j = v
 				}
-			}
-			got := d.Sum(nil)
-			if !bytes.Equal(got, want) {
-				t.Errorf("Unaligned writes, implementation=%s, alg=%s\ngot %q, want %q", impl, alg, got, want)
+				d.Write(buf[i : i+j])
+				i += j
 			}
 		}
+		got := d.Sum(nil)
+		if !bytes.Equal(got, want) {
+			t.Errorf("Unaligned writes, alg=%s\ngot %q, want %q", alg, got, want)
+		}
+	}

-		// Same for SHAKE
-		for alg, df := range testShakes {
-			want := make([]byte, 16)
-			got := make([]byte, 16)
-			d := df.constructor([]byte(df.defAlgoName), []byte(df.defCustomStr))
+	// Same for SHAKE
+	for alg, df := range testShakes {
+		want := make([]byte, 16)
+		got := make([]byte, 16)
+		d := df.constructor([]byte(df.defAlgoName), []byte(df.defCustomStr))

-			d.Reset()
-			d.Write(buf)
-			d.Read(want)
-			d.Reset()
-			for i := 0; i < len(buf); {
-				// Cycle through offsets which make a 137 byte sequence.
-				// Because 137 is prime this sequence should exercise all corner cases.
-				offsets := [17]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 1}
-				for _, j := range offsets {
-					if v := len(buf) - i; v < j {
-						j = v
-					}
-					d.Write(buf[i : i+j])
-					i += j
+		d.Reset()
+		d.Write(buf)
+		d.Read(want)
+		d.Reset()
+		for i := 0; i < len(buf); {
+			// Cycle through offsets which make a 137 byte sequence.
+			// Because 137 is prime this sequence should exercise all corner cases.
+			offsets := [17]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 1}
+			for _, j := range offsets {
+				if v := len(buf) - i; v < j {
+					j = v
 				}
-			}
-			d.Read(got)
-			if !bytes.Equal(got, want) {
-				t.Errorf("Unaligned writes, implementation=%s, alg=%s\ngot %q, want %q", impl, alg, got, want)
+				d.Write(buf[i : i+j])
+				i += j
 			}
 		}
-	})
+		d.Read(got)
+		if !bytes.Equal(got, want) {
+			t.Errorf("Unaligned writes, alg=%s\ngot %q, want %q", alg, got, want)
+		}
+	}
 }

 // TestAppend checks that appending works when reallocation is necessary.
 func TestAppend(t *testing.T) {
-	testUnalignedAndGeneric(t, func(impl string) {
-		d := New224()
+	d := New224()

-		for capacity := 2; capacity <= 66; capacity += 64 {
-			// The first time around the loop, Sum will have to reallocate.
-			// The second time, it will not.
-			buf := make([]byte, 2, capacity)
-			d.Reset()
-			d.Write([]byte{0xcc})
-			buf = d.Sum(buf)
-			expected := "0000DF70ADC49B2E76EEE3A6931B93FA41841C3AF2CDF5B32A18B5478C39"
-			if got := strings.ToUpper(hex.EncodeToString(buf)); got != expected {
-				t.Errorf("got %s, want %s", got, expected)
-			}
+	for capacity := 2; capacity <= 66; capacity += 64 {
+		// The first time around the loop, Sum will have to reallocate.
+		// The second time, it will not.
+		buf := make([]byte, 2, capacity)
+		d.Reset()
+		d.Write([]byte{0xcc})
+		buf = d.Sum(buf)
+		expected := "0000DF70ADC49B2E76EEE3A6931B93FA41841C3AF2CDF5B32A18B5478C39"
+		if got := strings.ToUpper(hex.EncodeToString(buf)); got != expected {
+			t.Errorf("got %s, want %s", got, expected)
 		}
-	})
+	}
 }

 // TestAppendNoRealloc tests that appending works when no reallocation is necessary.
 func TestAppendNoRealloc(t *testing.T) {
-	testUnalignedAndGeneric(t, func(impl string) {
-		buf := make([]byte, 1, 200)
-		d := New224()
-		d.Write([]byte{0xcc})
-		buf = d.Sum(buf)
-		expected := "00DF70ADC49B2E76EEE3A6931B93FA41841C3AF2CDF5B32A18B5478C39"
-		if got := strings.ToUpper(hex.EncodeToString(buf)); got != expected {
-			t.Errorf("%s: got %s, want %s", impl, got, expected)
-		}
-	})
+	buf := make([]byte, 1, 200)
+	d := New224()
+	d.Write([]byte{0xcc})
+	buf = d.Sum(buf)
+	expected := "00DF70ADC49B2E76EEE3A6931B93FA41841C3AF2CDF5B32A18B5478C39"
+	if got := strings.ToUpper(hex.EncodeToString(buf)); got != expected {
+		t.Errorf("got %s, want %s", got, expected)
+	}
 }

 // TestSqueezing checks that squeezing the full output a single time produces
 // the same output as repeatedly squeezing the instance.
 func TestSqueezing(t *testing.T) {
-	testUnalignedAndGeneric(t, func(impl string) {
-		for algo, v := range testShakes {
-			d0 := v.constructor([]byte(v.defAlgoName), []byte(v.defCustomStr))
-			d0.Write([]byte(testString))
-			ref := make([]byte, 32)
-			d0.Read(ref)
+	for algo, v := range testShakes {
+		d0 := v.constructor([]byte(v.defAlgoName), []byte(v.defCustomStr))
+		d0.Write([]byte(testString))
+		ref := make([]byte, 32)
+		d0.Read(ref)

-			d1 := v.constructor([]byte(v.defAlgoName), []byte(v.defCustomStr))
-			d1.Write([]byte(testString))
-			var multiple []byte
-			for range ref {
-				one := make([]byte, 1)
-				d1.Read(one)
-				multiple = append(multiple, one...)
-			}
-			if !bytes.Equal(ref, multiple) {
-				t.Errorf("%s (%s): squeezing %d bytes one at a time failed", algo, impl, len(ref))
-			}
+		d1 := v.constructor([]byte(v.defAlgoName), []byte(v.defCustomStr))
+		d1.Write([]byte(testString))
+		var multiple []byte
+		for range ref {
+			one := make([]byte, 1)
+			d1.Read(one)
+			multiple = append(multiple, one...)
 		}
-	})
+		if !bytes.Equal(ref, multiple) {
+			t.Errorf("%s: squeezing %d bytes one at a time failed", algo, len(ref))
+		}
+	}
 }

 // sequentialBytes produces a buffer of size consecutive bytes 0x00, 0x01, ..., used for testing.
@@ -2,22 +2,39 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

-//go:build (!amd64 && !386 && !ppc64le) || purego
-
 package sha3

-// A storageBuf is an aligned array of maxRate bytes.
-type storageBuf [maxRate]byte
+import (
+	"crypto/subtle"
+	"encoding/binary"
+	"unsafe"

-func (b *storageBuf) asBytes() *[maxRate]byte {
-	return (*[maxRate]byte)(b)
-}
-
-var (
-	xorIn            = xorInGeneric
-	copyOut          = copyOutGeneric
-	xorInUnaligned   = xorInGeneric
-	copyOutUnaligned = copyOutGeneric
+	"golang.org/x/sys/cpu"
 )

-const xorImplementationUnaligned = "generic"
+// xorIn xors the bytes in buf into the state.
+func xorIn(d *state, buf []byte) {
+	if cpu.IsBigEndian {
+		for i := 0; len(buf) >= 8; i++ {
+			a := binary.LittleEndian.Uint64(buf)
+			d.a[i] ^= a
+			buf = buf[8:]
+		}
+	} else {
+		ab := (*[25 * 64 / 8]byte)(unsafe.Pointer(&d.a))
+		subtle.XORBytes(ab[:], ab[:], buf)
+	}
+}
+
+// copyOut copies uint64s to a byte buffer.
+func copyOut(d *state, b []byte) {
+	if cpu.IsBigEndian {
+		for i := 0; len(b) >= 8; i++ {
+			binary.LittleEndian.PutUint64(b, d.a[i])
+			b = b[8:]
+		}
+	} else {
+		ab := (*[25 * 64 / 8]byte)(unsafe.Pointer(&d.a))
+		copy(b, ab[:])
+	}
+}
@@ -1,28 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package sha3
-
-import "encoding/binary"
-
-// xorInGeneric xors the bytes in buf into the state; it
-// makes no non-portable assumptions about memory layout
-// or alignment.
-func xorInGeneric(d *state, buf []byte) {
-	n := len(buf) / 8
-
-	for i := 0; i < n; i++ {
-		a := binary.LittleEndian.Uint64(buf)
-		d.a[i] ^= a
-		buf = buf[8:]
-	}
-}
-
-// copyOutGeneric copies uint64s to a byte buffer.
-func copyOutGeneric(d *state, b []byte) {
-	for i := 0; len(b) >= 8; i++ {
-		binary.LittleEndian.PutUint64(b, d.a[i])
-		b = b[8:]
-	}
-}
@@ -1,66 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build (amd64 || 386 || ppc64le) && !purego
-
-package sha3
-
-import "unsafe"
-
-// A storageBuf is an aligned array of maxRate bytes.
-type storageBuf [maxRate / 8]uint64
-
-func (b *storageBuf) asBytes() *[maxRate]byte {
-	return (*[maxRate]byte)(unsafe.Pointer(b))
-}
-
-// xorInUnaligned uses unaligned reads and writes to update d.a to contain d.a
-// XOR buf.
-func xorInUnaligned(d *state, buf []byte) {
-	n := len(buf)
-	bw := (*[maxRate / 8]uint64)(unsafe.Pointer(&buf[0]))[: n/8 : n/8]
-	if n >= 72 {
-		d.a[0] ^= bw[0]
-		d.a[1] ^= bw[1]
-		d.a[2] ^= bw[2]
-		d.a[3] ^= bw[3]
-		d.a[4] ^= bw[4]
-		d.a[5] ^= bw[5]
-		d.a[6] ^= bw[6]
-		d.a[7] ^= bw[7]
-		d.a[8] ^= bw[8]
-	}
-	if n >= 104 {
-		d.a[9] ^= bw[9]
-		d.a[10] ^= bw[10]
-		d.a[11] ^= bw[11]
-		d.a[12] ^= bw[12]
-	}
-	if n >= 136 {
-		d.a[13] ^= bw[13]
-		d.a[14] ^= bw[14]
-		d.a[15] ^= bw[15]
-		d.a[16] ^= bw[16]
-	}
-	if n >= 144 {
-		d.a[17] ^= bw[17]
-	}
-	if n >= 168 {
-		d.a[18] ^= bw[18]
-		d.a[19] ^= bw[19]
-		d.a[20] ^= bw[20]
-	}
-}
-
-func copyOutUnaligned(d *state, buf []byte) {
-	ab := (*[maxRate]uint8)(unsafe.Pointer(&d.a[0]))
-	copy(buf, ab[:])
-}
-
-var (
-	xorIn   = xorInUnaligned
-	copyOut = copyOutUnaligned
-)
-
-const xorImplementationUnaligned = "unaligned"