feat: add hdwallet derived function

pkg/hdwallet/path.go

@@ -0,0 +1,70 @@
+package hdwallet
+
+import (
+	"crypto/hmac"
+	"crypto/sha512"
+	"encoding/binary"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+type Key struct {
+	PrivateKey []byte
+	ChainCode  []byte
+}
+
+func CKDPriv(key Key, index uint32) Key {
+	buffer := make([]byte, 0, 1+4+len(key.PrivateKey))
+	buffer = append(buffer, 0)
+	buffer = append(buffer, key.PrivateKey...)
+	v := make([]byte, 4)
+	binary.BigEndian.PutUint32(v, index)
+	buffer = append(buffer, v...)
+
+	I := hamc512(key.ChainCode, buffer)
+
+	return Key{
+		PrivateKey: I[:32],
+		ChainCode:  I[32:],
+	}
+}
+
+func CreateMasterKey(seed []byte) Key {
+	I := hamc512([]byte("ed25519 seed"), seed)
+	return Key{
+		PrivateKey: I[:32],
+		ChainCode:  I[32:],
+	}
+}
+
+func hamc512(key, data []byte) []byte {
+	hmac := hmac.New(sha512.New, key)
+	hmac.Write(data)
+	return hmac.Sum(nil)
+}
+
+func isValidPath(path string) bool {
+	r := regexp.MustCompile(`^m{1,1}(/\d+')*$`)
+	return r.MatchString(path)
+}
+
+func Derived(path string, seed []byte) (Key, error) {
+	if !isValidPath(path) {
+		return Key{}, fmt.Errorf("invalid path: %v", path)
+	}
+
+	key := CreateMasterKey(seed)
+
+	for _, s := range strings.Split(path, "/")[1:] {
+		v, err := strconv.ParseUint(s[:len(s)-1], 10, 32)
+		if err != nil {
+			return Key{}, fmt.Errorf("failed to parse %v as a uint, err: %v", v, err)
+		}
+
+		key = CKDPriv(key, uint32(v)+1<<31)
+	}
+
+	return key, nil
+}

pkg/hdwallet/path_test.go

@@ -0,0 +1,190 @@
+package hdwallet
+
+import (
+	"encoding/hex"
+	"reflect"
+	"testing"
+)
+
+func TestVerifyPath(t *testing.T) {
+	type args struct {
+		path string
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{args: args{path: "m"}, want: true},
+		{args: args{path: "m/"}, want: false},
+		{args: args{path: "m/44"}, want: false},
+		{args: args{path: "m/44/"}, want: false},
+		{args: args{path: "m/44'"}, want: true},
+		{args: args{path: "m/44'/"}, want: false},
+		{args: args{path: "m/100000000'"}, want: true},
+		{args: args{path: "m/44/501'/1'"}, want: false},
+		{args: args{path: "m/44'/501/1'"}, want: false},
+		{args: args{path: "m/44'/501/1'/0'"}, want: false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := isValidPath(tt.args.path); got != tt.want {
+				t.Errorf("VerifyPath() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDerived(t *testing.T) {
+	type args struct {
+		seed []byte
+		path string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    Key
+		wantErr bool
+	}{
+		{
+			args: args{
+				seed: mustDecodeHex("000102030405060708090a0b0c0d0e0f"),
+				path: "m",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("90046a93de5380a72b5e45010748567d5ea02bbf6522f979e05c0d8d8ca9fffb"),
+				PrivateKey: mustDecodeHex("2b4be7f19ee27bbf30c667b642d5f4aa69fd169872f8fc3059c08ebae2eb19e7"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("000102030405060708090a0b0c0d0e0f"),
+				path: "m/0'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("8b59aa11380b624e81507a27fedda59fea6d0b779a778918a2fd3590e16e9c69"),
+				PrivateKey: mustDecodeHex("68e0fe46dfb67e368c75379acec591dad19df3cde26e63b93a8e704f1dade7a3"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("000102030405060708090a0b0c0d0e0f"),
+				path: "m/0'/1'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("a320425f77d1b5c2505a6b1b27382b37368ee640e3557c315416801243552f14"),
+				PrivateKey: mustDecodeHex("b1d0bad404bf35da785a64ca1ac54b2617211d2777696fbffaf208f746ae84f2"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("000102030405060708090a0b0c0d0e0f"),
+				path: "m/0'/1'/2'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("2e69929e00b5ab250f49c3fb1c12f252de4fed2c1db88387094a0f8c4c9ccd6c"),
+				PrivateKey: mustDecodeHex("92a5b23c0b8a99e37d07df3fb9966917f5d06e02ddbd909c7e184371463e9fc9"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("000102030405060708090a0b0c0d0e0f"),
+				path: "m/0'/1'/2'/2'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("8f6d87f93d750e0efccda017d662a1b31a266e4a6f5993b15f5c1f07f74dd5cc"),
+				PrivateKey: mustDecodeHex("30d1dc7e5fc04c31219ab25a27ae00b50f6fd66622f6e9c913253d6511d1e662"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("000102030405060708090a0b0c0d0e0f"),
+				path: "m/0'/1'/2'/2'/1000000000'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("68789923a0cac2cd5a29172a475fe9e0fb14cd6adb5ad98a3fa70333e7afa230"),
+				PrivateKey: mustDecodeHex("8f94d394a8e8fd6b1bc2f3f49f5c47e385281d5c17e65324b0f62483e37e8793"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("fffcf9f6f3f0edeae7e4e1dedbd8d5d2cfccc9c6c3c0bdbab7b4b1aeaba8a5a29f9c999693908d8a8784817e7b7875726f6c696663605d5a5754514e4b484542"),
+				path: "m",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("ef70a74db9c3a5af931b5fe73ed8e1a53464133654fd55e7a66f8570b8e33c3b"),
+				PrivateKey: mustDecodeHex("171cb88b1b3c1db25add599712e36245d75bc65a1a5c9e18d76f9f2b1eab4012"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("fffcf9f6f3f0edeae7e4e1dedbd8d5d2cfccc9c6c3c0bdbab7b4b1aeaba8a5a29f9c999693908d8a8784817e7b7875726f6c696663605d5a5754514e4b484542"),
+				path: "m/0'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("0b78a3226f915c082bf118f83618a618ab6dec793752624cbeb622acb562862d"),
+				PrivateKey: mustDecodeHex("1559eb2bbec5790b0c65d8693e4d0875b1747f4970ae8b650486ed7470845635"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("fffcf9f6f3f0edeae7e4e1dedbd8d5d2cfccc9c6c3c0bdbab7b4b1aeaba8a5a29f9c999693908d8a8784817e7b7875726f6c696663605d5a5754514e4b484542"),
+				path: "m/0'/2147483647'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("138f0b2551bcafeca6ff2aa88ba8ed0ed8de070841f0c4ef0165df8181eaad7f"),
+				PrivateKey: mustDecodeHex("ea4f5bfe8694d8bb74b7b59404632fd5968b774ed545e810de9c32a4fb4192f4"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("fffcf9f6f3f0edeae7e4e1dedbd8d5d2cfccc9c6c3c0bdbab7b4b1aeaba8a5a29f9c999693908d8a8784817e7b7875726f6c696663605d5a5754514e4b484542"),
+				path: "m/0'/2147483647'/1'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("73bd9fff1cfbde33a1b846c27085f711c0fe2d66fd32e139d3ebc28e5a4a6b90"),
+				PrivateKey: mustDecodeHex("3757c7577170179c7868353ada796c839135b3d30554bbb74a4b1e4a5a58505c"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("fffcf9f6f3f0edeae7e4e1dedbd8d5d2cfccc9c6c3c0bdbab7b4b1aeaba8a5a29f9c999693908d8a8784817e7b7875726f6c696663605d5a5754514e4b484542"),
+				path: "m/0'/2147483647'/1'/2147483646'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("0902fe8a29f9140480a00ef244bd183e8a13288e4412d8389d140aac1794825a"),
+				PrivateKey: mustDecodeHex("5837736c89570de861ebc173b1086da4f505d4adb387c6a1b1342d5e4ac9ec72"),
+			},
+		},
+		{
+			args: args{
+				seed: mustDecodeHex("fffcf9f6f3f0edeae7e4e1dedbd8d5d2cfccc9c6c3c0bdbab7b4b1aeaba8a5a29f9c999693908d8a8784817e7b7875726f6c696663605d5a5754514e4b484542"),
+				path: "m/0'/2147483647'/1'/2147483646'/2'",
+			},
+			want: Key{
+				ChainCode:  mustDecodeHex("5d70af781f3a37b829f0d060924d5e960bdc02e85423494afc0b1a41bbe196d4"),
+				PrivateKey: mustDecodeHex("551d333177df541ad876a60ea71f00447931c0a9da16f227c11ea080d7391b8d"),
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := Derived(tt.args.path, tt.args.seed)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Derived() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Derived() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func mustDecodeHex(s string) []byte {
+	h, err := hex.DecodeString(s)
+	if err != nil {
+		panic(err)
+	}
+	return h
+}