sealer: Utils for reading commitments from cache + unit tests

storage/sealer/commitment/commd.go

@@ -0,0 +1,34 @@
+package commitment
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+)
+
+const treeDFile = "sc-02-data-tree-d.dat"
+
+// TreeDCommD reads CommD from tree-d
+func TreeDCommD(cache string) ([32]byte, error) {
+	// Open the tree-d file for reading
+	file, err := os.Open(filepath.Join(cache, treeDFile))
+	if err != nil {
+		return [32]byte{}, err
+	}
+	defer file.Close() // nolint:errcheck
+
+	// Seek to 32 bytes from the end of the file
+	_, err = file.Seek(-32, io.SeekEnd)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	// Read the last 32 bytes
+	var commD [32]byte
+	_, err = file.Read(commD[:])
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	return commD, nil
+}

storage/sealer/commitment/commr.go

@@ -0,0 +1,64 @@
+package commitment
+
+import (
+	"math/big"
+	"os"
+	"path/filepath"
+
+	"github.com/triplewz/poseidon"
+	ff "github.com/triplewz/poseidon/bls12_381"
+	"golang.org/x/xerrors"
+)
+
+const pauxFile = "p_aux"
+
+func CommR(commC, commRLast [32]byte) ([32]byte, error) {
+	// reverse commC and commRLast so that endianness is correct
+	for i, j := 0, len(commC)-1; i < j; i, j = i+1, j-1 {
+		commC[i], commC[j] = commC[j], commC[i]
+		commRLast[i], commRLast[j] = commRLast[j], commRLast[i]
+	}
+
+	input_a := new(big.Int)
+	input_a.SetBytes(commC[:])
+	input_b := new(big.Int)
+	input_b.SetBytes(commRLast[:])
+	input := []*big.Int{input_a, input_b}
+
+	cons, err := poseidon.GenPoseidonConstants(3)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	h1, err := poseidon.Hash(input, cons, poseidon.OptimizedStatic)
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	h1element := new(ff.Element).SetBigInt(h1).Bytes()
+
+	// reverse the bytes so that endianness is correct
+	for i, j := 0, len(h1element)-1; i < j; i, j = i+1, j-1 {
+		h1element[i], h1element[j] = h1element[j], h1element[i]
+	}
+
+	return h1element, nil
+}
+
+// PAuxCommR reads p_aux and computes CommR
+func PAuxCommR(cache string) ([32]byte, error) {
+	commCcommRLast, err := os.ReadFile(filepath.Join(cache, pauxFile))
+	if err != nil {
+		return [32]byte{}, err
+	}
+
+	if len(commCcommRLast) != 64 {
+		return [32]byte{}, xerrors.Errorf("invalid commCcommRLast length %d", len(commCcommRLast))
+	}
+
+	var commC, commRLast [32]byte
+	copy(commC[:], commCcommRLast[:32])
+	copy(commRLast[:], commCcommRLast[32:])
+
+	return CommR(commC, commRLast)
+}

storage/sealer/commitment/commr_test.go

@@ -0,0 +1,35 @@
+package commitment
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCommR(t *testing.T) {
+	var commC = [32]byte{
+		0x09, 0x1e, 0x07, 0x3b, 0x98, 0x2f, 0x66, 0xf0,
+		0x13, 0xc0, 0x26, 0xda, 0x6e, 0x54, 0xd8, 0x7d,
+		0xbf, 0x8b, 0xba, 0x84, 0x8e, 0xf5, 0x7a, 0x55,
+		0x29, 0xc7, 0xe7, 0xf7, 0x2c, 0x82, 0x88, 0x43,
+	}
+
+	var commRLast = [32]byte{
+		0xf0, 0xc5, 0x78, 0x5c, 0x6c, 0x8c, 0xf6, 0x2d,
+		0x96, 0x8b, 0x1e, 0xcd, 0x68, 0xed, 0xb9, 0xd9,
+		0x1e, 0xb9, 0x44, 0x5c, 0x78, 0x58, 0xa6, 0x00,
+		0x26, 0xf8, 0x82, 0x68, 0x60, 0xf7, 0xe7, 0x68,
+	}
+
+	res, err := CommR(commC, commRLast)
+	require.NoError(t, err)
+
+	var expected = [32]byte{
+		0xe6, 0x74, 0xd1, 0x9e, 0x6c, 0xe7, 0xfc, 0xf3,
+		0x3b, 0xbf, 0xd9, 0xb3, 0x43, 0xa0, 0xce, 0xb1,
+		0x2d, 0x28, 0x31, 0xd1, 0xda, 0x54, 0x31, 0x61,
+		0x89, 0x1e, 0xbc, 0xca, 0xd2, 0xc6, 0xdb, 0x01,
+	}
+
+	require.Equal(t, res, expected)
+}