Merge pull request #1 from keep-network/f-function

F compression function implementation for Blake2b

f.go

@@ -0,0 +1,199 @@
+// Copyright 2016 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.
+//
+// Modified by KEEP SEZC to expose F compression function.
+//
+package blake2
+
+import (
+	"encoding/binary"
+	"math/bits"
+)
+
+const (
+	// BlockSize is the blocksize of BLAKE2 in bytes.
+	BlockSize = 128
+)
+
+var iv = [8]uint64{
+	0x6a09e667f3bcc908, 0xbb67ae8584caa73b, 0x3c6ef372fe94f82b, 0xa54ff53a5f1d36f1,
+	0x510e527fade682d1, 0x9b05688c2b3e6c1f, 0x1f83d9abfb41bd6b, 0x5be0cd19137e2179,
+}
+
+// the precomputed values for the first 10 rounds of BLAKE2
+// there are 10 16-byte arrays - one for each round
+// the entries are calculated from the sigma constants.
+var precomputed = [10][16]byte{
+	{0, 2, 4, 6, 1, 3, 5, 7, 8, 10, 12, 14, 9, 11, 13, 15},
+	{14, 4, 9, 13, 10, 8, 15, 6, 1, 0, 11, 5, 12, 2, 7, 3},
+	{11, 12, 5, 15, 8, 0, 2, 13, 10, 3, 7, 9, 14, 6, 1, 4},
+	{7, 3, 13, 11, 9, 1, 12, 14, 2, 5, 4, 15, 6, 10, 0, 8},
+	{9, 5, 2, 10, 0, 7, 4, 15, 14, 11, 6, 3, 1, 12, 8, 13},
+	{2, 6, 0, 8, 12, 10, 11, 3, 4, 7, 15, 1, 13, 5, 14, 9},
+	{12, 1, 14, 4, 5, 15, 13, 10, 0, 6, 9, 8, 7, 3, 2, 11},
+	{13, 7, 12, 3, 11, 14, 1, 9, 5, 15, 8, 2, 0, 4, 6, 10},
+	{6, 14, 11, 0, 15, 9, 3, 8, 12, 13, 1, 10, 2, 7, 4, 5},
+	{10, 8, 7, 1, 2, 4, 6, 5, 15, 9, 3, 13, 11, 14, 12, 0},
+}
+
+// F is a compression function for Blake2. It takes as an argument the state
+// vector `h`, message block vector `mb`, offset counter `t`, final
+// block indicator flag `f`, and number of rounds `rounds`. The state vector
+// provided as the first parameter is modified by the function.
+func F(h *[8]uint64, mb [BlockSize]byte, t *[2]uint64, f bool, rounds int) {
+	var m [16]uint64
+	t0, t1 := t[0], t[1]
+
+	for i := 0; i < len(mb); {
+		t0 += BlockSize
+		if t0 < BlockSize {
+			t1++
+		}
+
+		v0, v1, v2, v3, v4, v5, v6, v7 := h[0], h[1], h[2], h[3], h[4], h[5], h[6], h[7]
+		v8, v9, v10, v11, v12, v13, v14, v15 := iv[0], iv[1], iv[2], iv[3], iv[4], iv[5], iv[6], iv[7]
+		v12 ^= t0
+		v13 ^= t1
+
+		if f {
+			v14 ^= 0xffffffffffffffff
+		}
+
+		for j := range m {
+			m[j] = binary.LittleEndian.Uint64(mb[i:])
+			i += 8
+		}
+
+		for j := 0; j < rounds; j++ {
+			s := &(precomputed[j%10])
+
+			v0 += m[s[0]]
+			v0 += v4
+			v12 ^= v0
+			v12 = bits.RotateLeft64(v12, -32)
+			v8 += v12
+			v4 ^= v8
+			v4 = bits.RotateLeft64(v4, -24)
+			v1 += m[s[1]]
+			v1 += v5
+			v13 ^= v1
+			v13 = bits.RotateLeft64(v13, -32)
+			v9 += v13
+			v5 ^= v9
+			v5 = bits.RotateLeft64(v5, -24)
+			v2 += m[s[2]]
+			v2 += v6
+			v14 ^= v2
+			v14 = bits.RotateLeft64(v14, -32)
+			v10 += v14
+			v6 ^= v10
+			v6 = bits.RotateLeft64(v6, -24)
+			v3 += m[s[3]]
+			v3 += v7
+			v15 ^= v3
+			v15 = bits.RotateLeft64(v15, -32)
+			v11 += v15
+			v7 ^= v11
+			v7 = bits.RotateLeft64(v7, -24)
+
+			v0 += m[s[4]]
+			v0 += v4
+			v12 ^= v0
+			v12 = bits.RotateLeft64(v12, -16)
+			v8 += v12
+			v4 ^= v8
+			v4 = bits.RotateLeft64(v4, -63)
+			v1 += m[s[5]]
+			v1 += v5
+			v13 ^= v1
+			v13 = bits.RotateLeft64(v13, -16)
+			v9 += v13
+			v5 ^= v9
+			v5 = bits.RotateLeft64(v5, -63)
+			v2 += m[s[6]]
+			v2 += v6
+			v14 ^= v2
+			v14 = bits.RotateLeft64(v14, -16)
+			v10 += v14
+			v6 ^= v10
+			v6 = bits.RotateLeft64(v6, -63)
+			v3 += m[s[7]]
+			v3 += v7
+			v15 ^= v3
+			v15 = bits.RotateLeft64(v15, -16)
+			v11 += v15
+			v7 ^= v11
+			v7 = bits.RotateLeft64(v7, -63)
+
+			v0 += m[s[8]]
+			v0 += v5
+			v15 ^= v0
+			v15 = bits.RotateLeft64(v15, -32)
+			v10 += v15
+			v5 ^= v10
+			v5 = bits.RotateLeft64(v5, -24)
+			v1 += m[s[9]]
+			v1 += v6
+			v12 ^= v1
+			v12 = bits.RotateLeft64(v12, -32)
+			v11 += v12
+			v6 ^= v11
+			v6 = bits.RotateLeft64(v6, -24)
+			v2 += m[s[10]]
+			v2 += v7
+			v13 ^= v2
+			v13 = bits.RotateLeft64(v13, -32)
+			v8 += v13
+			v7 ^= v8
+			v7 = bits.RotateLeft64(v7, -24)
+			v3 += m[s[11]]
+			v3 += v4
+			v14 ^= v3
+			v14 = bits.RotateLeft64(v14, -32)
+			v9 += v14
+			v4 ^= v9
+			v4 = bits.RotateLeft64(v4, -24)
+
+			v0 += m[s[12]]
+			v0 += v5
+			v15 ^= v0
+			v15 = bits.RotateLeft64(v15, -16)
+			v10 += v15
+			v5 ^= v10
+			v5 = bits.RotateLeft64(v5, -63)
+			v1 += m[s[13]]
+			v1 += v6
+			v12 ^= v1
+			v12 = bits.RotateLeft64(v12, -16)
+			v11 += v12
+			v6 ^= v11
+			v6 = bits.RotateLeft64(v6, -63)
+			v2 += m[s[14]]
+			v2 += v7
+			v13 ^= v2
+			v13 = bits.RotateLeft64(v13, -16)
+			v8 += v13
+			v7 ^= v8
+			v7 = bits.RotateLeft64(v7, -63)
+			v3 += m[s[15]]
+			v3 += v4
+			v14 ^= v3
+			v14 = bits.RotateLeft64(v14, -16)
+			v9 += v14
+			v4 ^= v9
+			v4 = bits.RotateLeft64(v4, -63)
+
+		}
+
+		h[0] ^= v0 ^ v8
+		h[1] ^= v1 ^ v9
+		h[2] ^= v2 ^ v10
+		h[3] ^= v3 ^ v11
+		h[4] ^= v4 ^ v12
+		h[5] ^= v5 ^ v13
+		h[6] ^= v6 ^ v14
+		h[7] ^= v7 ^ v15
+	}
+	t[0], t[1] = t0, t1
+}

f_test.go

@@ -0,0 +1,50 @@
+package blake2
+
+import (
+	"encoding/hex"
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestF_2b(t *testing.T) {
+	runTest(t, testVectors2b)
+}
+
+func TestF_2bX(t *testing.T) {
+	runTest(t, testVectors2bX)
+}
+
+func runTest(t *testing.T, testVectors []testVector) {
+	for i, test := range testVectors {
+		t.Run(fmt.Sprintf("test vector %v", i), func(t *testing.T) {
+			mDecoded, err := hex.DecodeString(test.mIn)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if len(mDecoded) != BlockSize {
+				t.Fatalf("unexpected message block vector length [%v]", len(mDecoded))
+			}
+
+			var m [BlockSize]byte
+			copy(m[:], mDecoded)
+			h := test.hIn
+			c := test.c
+
+			F(&h, m, &c, test.f, test.rounds)
+
+			if !reflect.DeepEqual(test.hOut, h) {
+				t.Errorf("Unexpected result\nExpected: [%v]\nActual:   [%v]\n", test.hOut, h)
+			}
+		})
+	}
+}
+
+type testVector struct {
+	mIn    string
+	hIn    [8]uint64
+	c      [2]uint64
+	f      bool
+	rounds int
+	hOut   [8]uint64
+}