diff --git a/browser/firefox/firefox.go b/browser/firefox/firefox.go
index 31778e7..7bde542 100644
--- a/browser/firefox/firefox.go
+++ b/browser/firefox/firefox.go
@@ -1,12 +1,18 @@
 package firefox
 
 import (
+	"bytes"
+	"database/sql"
 	"errors"
 	"fmt"
 	"io/fs"
+	"os"
 	"path/filepath"
 
+	_ "modernc.org/sqlite" // sqlite3 driver TODO: replace with chooseable driver
+
 	"github.com/moond4rk/hackbrowserdata/browsingdata"
+	"github.com/moond4rk/hackbrowserdata/crypto"
 	"github.com/moond4rk/hackbrowserdata/item"
 	"github.com/moond4rk/hackbrowserdata/utils/fileutil"
 	"github.com/moond4rk/hackbrowserdata/utils/typeutil"
@@ -68,8 +74,82 @@ func firefoxWalkFunc(items []item.Item, multiItemPaths map[string]map[item.Item]
 	}
 }
 
+// GetMasterKey returns master key of Firefox. from key4.db
 func (f *Firefox) GetMasterKey() ([]byte, error) {
-	return f.masterKey, nil
+	tempFilename := item.FirefoxKey4.TempFilename()
+
+	// Open and defer close of the database.
+	keyDB, err := sql.Open("sqlite", tempFilename)
+	if err != nil {
+		return nil, fmt.Errorf("open key4.db error: %w", err)
+	}
+	defer os.Remove(tempFilename)
+	defer keyDB.Close()
+
+	globalSalt, metaBytes, err := queryMetaData(keyDB)
+	if err != nil {
+		return nil, fmt.Errorf("query metadata error: %w", err)
+	}
+
+	nssA11, nssA102, err := queryNssPrivate(keyDB)
+	if err != nil {
+		return nil, fmt.Errorf("query NSS private error: %w", err)
+	}
+
+	return processMasterKey(globalSalt, metaBytes, nssA11, nssA102)
+}
+
+func queryMetaData(db *sql.DB) ([]byte, []byte, error) {
+	const query = `SELECT item1, item2 FROM metaData WHERE id = 'password'`
+	var globalSalt, metaBytes []byte
+	if err := db.QueryRow(query).Scan(&globalSalt, &metaBytes); err != nil {
+		return nil, nil, err
+	}
+	return globalSalt, metaBytes, nil
+}
+
+func queryNssPrivate(db *sql.DB) ([]byte, []byte, error) {
+	const query = `SELECT a11, a102 from nssPrivate`
+	var nssA11, nssA102 []byte
+	if err := db.QueryRow(query).Scan(&nssA11, &nssA102); err != nil {
+		return nil, nil, err
+	}
+	return nssA11, nssA102, nil
+}
+
+// processMasterKey process master key of Firefox.
+// Process the metaBytes and nssA11 with the corresponding cryptographic operations.
+func processMasterKey(globalSalt, metaBytes, nssA11, nssA102 []byte) ([]byte, error) {
+	metaPBE, err := crypto.NewASN1PBE(metaBytes)
+	if err != nil {
+		return nil, err
+	}
+
+	k, err := metaPBE.Decrypt(globalSalt)
+	if err != nil {
+		return nil, err
+	}
+
+	if !bytes.Contains(k, []byte("password-check")) {
+		return nil, errors.New("password-check not found")
+	}
+	keyLin := []byte{248, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
+	if !bytes.Equal(nssA102, keyLin) {
+		return nil, errors.New("nssA102 not equal keyLin")
+	}
+	nssPBE, err := crypto.NewASN1PBE(nssA11)
+	if err != nil {
+		return nil, err
+	}
+	finallyKey, err := nssPBE.Decrypt(globalSalt)
+	if err != nil {
+		return nil, err
+	}
+	if len(finallyKey) < 24 {
+		return nil, errors.New("finallyKey length less than 24")
+	}
+	finallyKey = finallyKey[:24]
+	return finallyKey, nil
 }
 
 func (f *Firefox) Name() string {
diff --git a/browser/firefox/firefox_test.go b/browser/firefox/firefox_test.go
new file mode 100644
index 0000000..74c9dac
--- /dev/null
+++ b/browser/firefox/firefox_test.go
@@ -0,0 +1,38 @@
+package firefox
+
+import (
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestQueryMetaData(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	assert.NoError(t, err)
+	defer db.Close()
+
+	rows := sqlmock.NewRows([]string{"item1", "item2"}).
+		AddRow([]byte("globalSalt"), []byte("metaBytes"))
+	mock.ExpectQuery("SELECT item1, item2 FROM metaData WHERE id = 'password'").WillReturnRows(rows)
+
+	globalSalt, metaBytes, err := queryMetaData(db)
+	assert.NoError(t, err)
+	assert.Equal(t, []byte("globalSalt"), globalSalt)
+	assert.Equal(t, []byte("metaBytes"), metaBytes)
+}
+
+func TestQueryNssPrivate(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	assert.NoError(t, err)
+	defer db.Close()
+
+	rows := sqlmock.NewRows([]string{"a11", "a102"}).
+		AddRow([]byte("nssA11"), []byte("nssA102"))
+	mock.ExpectQuery("SELECT a11, a102 from nssPrivate").WillReturnRows(rows)
+
+	nssA11, nssA102, err := queryNssPrivate(db)
+	assert.NoError(t, err)
+	assert.Equal(t, []byte("nssA11"), nssA11)
+	assert.Equal(t, []byte("nssA102"), nssA102)
+}
diff --git a/browsingdata/password/password.go b/browsingdata/password/password.go
index 2915e8f..6bf3192 100644
--- a/browsingdata/password/password.go
+++ b/browsingdata/password/password.go
@@ -1,7 +1,6 @@
 package password
 
 import (
-	"bytes"
 	"database/sql"
 	"encoding/base64"
 	"log/slog"
@@ -169,87 +168,42 @@ const (
 )
 
 func (f *FirefoxPassword) Parse(masterKey []byte) error {
-	globalSalt, metaBytes, nssA11, nssA102, err := getFirefoxDecryptKey(item.FirefoxKey4.TempFilename())
-	if err != nil {
-		return err
-	}
-	metaPBE, err := crypto.NewASN1PBE(metaBytes)
+	logins, err := getFirefoxLoginData()
 	if err != nil {
 		return err
 	}
 
-	k, err := metaPBE.Decrypt(globalSalt, masterKey)
-	if err != nil {
-		return err
-	}
-	if bytes.Contains(k, []byte("password-check")) {
-		keyLin := []byte{248, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
-		if bytes.Equal(nssA102, keyLin) {
-			nssPBE, err := crypto.NewASN1PBE(nssA11)
-			if err != nil {
-				return err
-			}
-			finallyKey, err := nssPBE.Decrypt(globalSalt, masterKey)
-			if err != nil {
-				return err
-			}
-
-			finallyKey = finallyKey[:24]
-			logins, err := getFirefoxLoginData()
-			if err != nil {
-				return err
-			}
-
-			for _, v := range logins {
-				userPBE, err := crypto.NewASN1PBE(v.encryptUser)
-				if err != nil {
-					return err
-				}
-				pwdPBE, err := crypto.NewASN1PBE(v.encryptPass)
-				if err != nil {
-					return err
-				}
-				user, err := userPBE.Decrypt(finallyKey, masterKey)
-				if err != nil {
-					return err
-				}
-				pwd, err := pwdPBE.Decrypt(finallyKey, masterKey)
-				if err != nil {
-					return err
-				}
-				*f = append(*f, loginData{
-					LoginURL:   v.LoginURL,
-					UserName:   string(user),
-					Password:   string(pwd),
-					CreateDate: v.CreateDate,
-				})
-			}
+	for _, v := range logins {
+		userPBE, err := crypto.NewASN1PBE(v.encryptUser)
+		if err != nil {
+			return err
 		}
+		pwdPBE, err := crypto.NewASN1PBE(v.encryptPass)
+		if err != nil {
+			return err
+		}
+		user, err := userPBE.Decrypt(masterKey)
+		if err != nil {
+			return err
+		}
+		pwd, err := pwdPBE.Decrypt(masterKey)
+		if err != nil {
+			return err
+		}
+		*f = append(*f, loginData{
+			LoginURL:   v.LoginURL,
+			UserName:   string(user),
+			Password:   string(pwd),
+			CreateDate: v.CreateDate,
+		})
 	}
+
 	sort.Slice(*f, func(i, j int) bool {
 		return (*f)[i].CreateDate.After((*f)[j].CreateDate)
 	})
 	return nil
 }
 
-func getFirefoxDecryptKey(key4file string) (item1, item2, a11, a102 []byte, err error) {
-	keyDB, err := sql.Open("sqlite", key4file)
-	if err != nil {
-		return nil, nil, nil, nil, err
-	}
-	defer os.Remove(key4file)
-	defer keyDB.Close()
-
-	if err = keyDB.QueryRow(queryMetaData).Scan(&item1, &item2); err != nil {
-		return nil, nil, nil, nil, err
-	}
-
-	if err = keyDB.QueryRow(queryNssPrivate).Scan(&a11, &a102); err != nil {
-		return nil, nil, nil, nil, err
-	}
-	return item1, item2, a11, a102, nil
-}
-
 func getFirefoxLoginData() ([]loginData, error) {
 	s, err := os.ReadFile(item.FirefoxPassword.TempFilename())
 	if err != nil {
diff --git a/crypto/crypto.go b/crypto/crypto.go
index 04d47d9..457f92a 100644
--- a/crypto/crypto.go
+++ b/crypto/crypto.go
@@ -20,7 +20,7 @@ var (
 )
 
 type ASN1PBE interface {
-	Decrypt(globalSalt, masterPwd []byte) (key []byte, err error)
+	Decrypt(globalSalt []byte) (key []byte, err error)
 }
 
 func NewASN1PBE(b []byte) (pbe ASN1PBE, err error) {
@@ -60,9 +60,8 @@ type nssPBE struct {
 	Encrypted []byte
 }
 
-func (n nssPBE) Decrypt(globalSalt, masterPwd []byte) (key []byte, err error) {
-	glmp := append(globalSalt, masterPwd...)
-	hp := sha1.Sum(glmp)
+func (n nssPBE) Decrypt(globalSalt []byte) (key []byte, err error) {
+	hp := sha1.Sum(globalSalt)
 	s := append(hp[:], n.salt()...)
 	chp := sha1.Sum(s)
 	pes := paddingZero(n.salt(), 20)
@@ -134,7 +133,7 @@ type slatAttr struct {
 	}
 }
 
-func (m metaPBE) Decrypt(globalSalt, _ []byte) (key2 []byte, err error) {
+func (m metaPBE) Decrypt(globalSalt []byte) (key2 []byte, err error) {
 	k := sha1.Sum(globalSalt)
 	key := pbkdf2.Key(k[:], m.salt(), m.iterationCount(), m.keySize(), sha256.New)
 	iv := append([]byte{4, 14}, m.iv()...)
@@ -177,7 +176,7 @@ type loginPBE struct {
 	Encrypted []byte
 }
 
-func (l loginPBE) Decrypt(globalSalt, _ []byte) (key []byte, err error) {
+func (l loginPBE) Decrypt(globalSalt []byte) (key []byte, err error) {
 	return des3Decrypt(globalSalt, l.iv(), l.encrypted())
 }
 
diff --git a/go.mod b/go.mod
index c75893a..c77c977 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module github.com/moond4rk/hackbrowserdata
 go 1.21
 
 require (
+	github.com/DATA-DOG/go-sqlmock v1.5.2
 	github.com/gocarina/gocsv v0.0.0-20231116093920-b87c2d0e983a
 	github.com/godbus/dbus/v5 v5.1.0
 	github.com/otiai10/copy v1.14.0
diff --git a/go.sum b/go.sum
index c4f10d9..8d75f8f 100644
--- a/go.sum
+++ b/go.sum
@@ -1,3 +1,5 @@
+github.com/DATA-DOG/go-sqlmock v1.5.2 h1:OcvFkGmslmlZibjAjaHm3L//6LiuBgolP7OputlJIzU=
+github.com/DATA-DOG/go-sqlmock v1.5.2/go.mod h1:88MAG/4G7SMwSE3CeA0ZKzrT5CiOU3OJ+JlNzwDqpNU=
 github.com/cpuguy83/go-md2man/v2 v2.0.2 h1:p1EgwI/C7NhT0JmVkwCD2ZBK8j4aeHQX2pMHHBfMQ6w=
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -23,6 +25,7 @@ github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 h1:Z9n2FFNUXsshfwJMBgNA0RU6/i7WVaAegv3PtuIHPMs=
 github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51/go.mod h1:CzGEWj7cYgsdH8dAjBGEr58BoE7ScuLd+fwFZ44+/x8=
+github.com/kisielk/sqlstruct v0.0.0-20201105191214-5f3e10d3ab46/go.mod h1:yyMNCyc/Ib3bDTKd379tNMpB/7/H5TjM2Y9QJ5THLbE=
 github.com/mattn/go-isatty v0.0.16 h1:bq3VjFmv/sOjHtdEhmkEV4x1AJtvUvOJ2PFAZ5+peKQ=
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
 github.com/mattn/go-sqlite3 v1.14.16 h1:yOQRA0RpS5PFz/oikGwBEqvAWhWg5ufRz4ETLjwpU1Y=