feat: implement SHA-512 algorithm to ProtectSheet (#1115)

chart.go

@@ -980,12 +980,12 @@ func (f *File) getFormatChart(format string, combo []string) (*formatChart, []*f
 			return formatSet, comboCharts, err
 		}
 		if _, ok := chartValAxNumFmtFormatCode[comboChart.Type]; !ok {
-			return formatSet, comboCharts, newUnsupportChartType(comboChart.Type)
+			return formatSet, comboCharts, newUnsupportedChartType(comboChart.Type)
 		}
 		comboCharts = append(comboCharts, comboChart)
 	}
 	if _, ok := chartValAxNumFmtFormatCode[formatSet.Type]; !ok {
-		return formatSet, comboCharts, newUnsupportChartType(formatSet.Type)
+		return formatSet, comboCharts, newUnsupportedChartType(formatSet.Type)
 	}
 	return formatSet, comboCharts, err
 }

crypt.go

@@ -43,6 +43,7 @@ var (
 	packageOffset              = 8 // First 8 bytes are the size of the stream
 	packageEncryptionChunkSize = 4096
 	iterCount                  = 50000
+	sheetProtectionSpinCount   = 1e5
 	oleIdentifier              = []byte{
 		0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1, 0x1a, 0xe1,
 	}
@@ -146,7 +147,7 @@ func Decrypt(raw []byte, opt *Options) (packageBuf []byte, err error) {
 	case "standard":
 		return standardDecrypt(encryptionInfoBuf, encryptedPackageBuf, opt)
 	default:
-		err = ErrUnsupportEncryptMechanism
+		err = ErrUnsupportedEncryptMechanism
 	}
 	return
 }
@@ -307,7 +308,7 @@ func encryptionMechanism(buffer []byte) (mechanism string, err error) {
 	} else if (versionMajor == 3 || versionMajor == 4) && versionMinor == 3 {
 		mechanism = "extensible"
 	}
-	err = ErrUnsupportEncryptMechanism
+	err = ErrUnsupportedEncryptMechanism
 	return
 }
 
@@ -387,14 +388,14 @@ func standardConvertPasswdToKey(header StandardEncryptionHeader, verifier Standa
 		key = hashing("sha1", iterator, key)
 	}
 	var block int
-	hfinal := hashing("sha1", key, createUInt32LEBuffer(block, 4))
+	hFinal := hashing("sha1", key, createUInt32LEBuffer(block, 4))
 	cbRequiredKeyLength := int(header.KeySize) / 8
 	cbHash := sha1.Size
 	buf1 := bytes.Repeat([]byte{0x36}, 64)
-	buf1 = append(standardXORBytes(hfinal, buf1[:cbHash]), buf1[cbHash:]...)
+	buf1 = append(standardXORBytes(hFinal, buf1[:cbHash]), buf1[cbHash:]...)
 	x1 := hashing("sha1", buf1)
 	buf2 := bytes.Repeat([]byte{0x5c}, 64)
-	buf2 = append(standardXORBytes(hfinal, buf2[:cbHash]), buf2[cbHash:]...)
+	buf2 = append(standardXORBytes(hFinal, buf2[:cbHash]), buf2[cbHash:]...)
 	x2 := hashing("sha1", buf2)
 	x3 := append(x1, x2...)
 	keyDerived := x3[:cbRequiredKeyLength]
@@ -417,7 +418,8 @@ func standardXORBytes(a, b []byte) []byte {
 // ECMA-376 Agile Encryption
 
 // agileDecrypt decrypt the CFB file format with ECMA-376 agile encryption.
-// Support cryptographic algorithm: MD4, MD5, RIPEMD-160, SHA1, SHA256, SHA384 and SHA512.
+// Support cryptographic algorithm: MD4, MD5, RIPEMD-160, SHA1, SHA256,
+// SHA384 and SHA512.
 func agileDecrypt(encryptionInfoBuf, encryptedPackageBuf []byte, opt *Options) (packageBuf []byte, err error) {
 	var encryptionInfo Encryption
 	if encryptionInfo, err = parseEncryptionInfo(encryptionInfoBuf[8:]); err != nil {
@@ -605,11 +607,55 @@ func createIV(blockKey interface{}, encryption Encryption) ([]byte, error) {
 	return iv, nil
 }
 
-// randomBytes returns securely generated random bytes. It will return an error if the system's
-// secure random number generator fails to function correctly, in which case the caller should not
-// continue.
+// randomBytes returns securely generated random bytes. It will return an
+// error if the system's secure random number generator fails to function
+// correctly, in which case the caller should not continue.
 func randomBytes(n int) ([]byte, error) {
 	b := make([]byte, n)
 	_, err := rand.Read(b)
 	return b, err
 }
+
+// ISO Write Protection Method
+
+// genISOPasswdHash implements the ISO password hashing algorithm by given
+// plaintext password, name of the cryptographic hash algorithm, salt value
+// and spin count.
+func genISOPasswdHash(passwd, hashAlgorithm, salt string, spinCount int) (hashValue, saltValue string, err error) {
+	if len(passwd) < 1 || len(passwd) > MaxFieldLength {
+		err = ErrPasswordLengthInvalid
+		return
+	}
+	hash, ok := map[string]string{
+		"MD4":     "md4",
+		"MD5":     "md5",
+		"SHA-1":   "sha1",
+		"SHA-256": "sha256",
+		"SHA-384": "sha384",
+		"SHA-512": "sha512",
+	}[hashAlgorithm]
+	if !ok {
+		err = ErrUnsupportedHashAlgorithm
+		return
+	}
+	var b bytes.Buffer
+	s, _ := randomBytes(16)
+	if salt != "" {
+		if s, err = base64.StdEncoding.DecodeString(salt); err != nil {
+			return
+		}
+	}
+	b.Write(s)
+	encoder := unicode.UTF16(unicode.LittleEndian, unicode.IgnoreBOM).NewEncoder()
+	passwordBuffer, _ := encoder.Bytes([]byte(passwd))
+	b.Write(passwordBuffer)
+	// Generate the initial hash.
+	key := hashing(hash, b.Bytes())
+	// Now regenerate until spin count.
+	for i := 0; i < spinCount; i++ {
+		iterator := createUInt32LEBuffer(i, 4)
+		key = hashing(hash, key, iterator)
+	}
+	hashValue, saltValue = base64.StdEncoding.EncodeToString(key), base64.StdEncoding.EncodeToString(s)
+	return
+}

crypt_test.go

@@ -28,11 +28,27 @@ func TestEncrypt(t *testing.T) {
 func TestEncryptionMechanism(t *testing.T) {
 	mechanism, err := encryptionMechanism([]byte{3, 0, 3, 0})
 	assert.Equal(t, mechanism, "extensible")
-	assert.EqualError(t, err, ErrUnsupportEncryptMechanism.Error())
+	assert.EqualError(t, err, ErrUnsupportedEncryptMechanism.Error())
 	_, err = encryptionMechanism([]byte{})
 	assert.EqualError(t, err, ErrUnknownEncryptMechanism.Error())
 }
 
 func TestHashing(t *testing.T) {
-	assert.Equal(t, hashing("unsupportHashAlgorithm", []byte{}), []uint8([]byte(nil)))
+	assert.Equal(t, hashing("unsupportedHashAlgorithm", []byte{}), []uint8([]byte(nil)))
+}
+
+func TestGenISOPasswdHash(t *testing.T) {
+	for hashAlgorithm, expected := range map[string][]string{
+		"MD4":     {"2lZQZUubVHLm/t6KsuHX4w==", "TTHjJdU70B/6Zq83XGhHVA=="},
+		"MD5":     {"HWbqyd4dKKCjk1fEhk2kuQ==", "8ADyorkumWCayIukRhlVKQ=="},
+		"SHA-1":   {"XErQIV3Ol+nhXkyCxrLTEQm+mSc=", "I3nDtyf59ASaNX1l6KpFnA=="},
+		"SHA-256": {"7oqMFyfED+mPrzRIBQ+KpKT4SClMHEPOZldliP15xAA=", "ru1R/w3P3Jna2Qo+EE8QiA=="},
+		"SHA-384": {"nMODLlxsC8vr0btcq0kp/jksg5FaI3az5Sjo1yZk+/x4bFzsuIvpDKUhJGAk/fzo", "Zjq9/jHlgOY6MzFDSlVNZg=="},
+		"SHA-512": {"YZ6jrGOFQgVKK3rDK/0SHGGgxEmFJglQIIRamZc2PkxVtUBp54fQn96+jVXEOqo6dtCSanqksXGcm/h3KaiR4Q==", "p5s/bybHBPtusI7EydTIrg=="},
+	} {
+		hashValue, saltValue, err := genISOPasswdHash("password", hashAlgorithm, expected[1], int(sheetProtectionSpinCount))
+		assert.NoError(t, err)
+		assert.Equal(t, expected[0], hashValue)
+		assert.Equal(t, expected[1], saltValue)
+	}
 }

datavalidation.go

@@ -29,7 +29,7 @@ const (
 	DataValidationTypeDate
 	DataValidationTypeDecimal
 	typeList // inline use
-	DataValidationTypeTextLeng
+	DataValidationTypeTextLength
 	DataValidationTypeTime
 	// DataValidationTypeWhole Integer
 	DataValidationTypeWhole
@@ -116,7 +116,7 @@ func (dd *DataValidation) SetInput(title, msg string) {
 func (dd *DataValidation) SetDropList(keys []string) error {
 	formula := strings.Join(keys, ",")
 	if MaxFieldLength < len(utf16.Encode([]rune(formula))) {
-		return ErrDataValidationFormulaLenth
+		return ErrDataValidationFormulaLength
 	}
 	dd.Formula1 = fmt.Sprintf(`<formula1>"%s"</formula1>`, formulaEscaper.Replace(formula))
 	dd.Type = convDataValidationType(typeList)
@@ -155,7 +155,7 @@ func (dd *DataValidation) SetRange(f1, f2 interface{}, t DataValidationType, o D
 	}
 	dd.Formula1, dd.Formula2 = formula1, formula2
 	dd.Type = convDataValidationType(t)
-	dd.Operator = convDataValidationOperatior(o)
+	dd.Operator = convDataValidationOperator(o)
 	return nil
 }
 
@@ -197,7 +197,7 @@ func convDataValidationType(t DataValidationType) string {
 		DataValidationTypeDate:       "date",
 		DataValidationTypeDecimal:    "decimal",
 		typeList:                     "list",
-		DataValidationTypeTextLeng: "textLength",
+		DataValidationTypeTextLength: "textLength",
 		DataValidationTypeTime:       "time",
 		DataValidationTypeWhole:      "whole",
 	}
@@ -206,8 +206,8 @@ func convDataValidationType(t DataValidationType) string {
 
 }
 
-// convDataValidationOperatior get excel data validation operator.
-func convDataValidationOperatior(o DataValidationOperator) string {
+// convDataValidationOperator get excel data validation operator.
+func convDataValidationOperator(o DataValidationOperator) string {
 	typeMap := map[DataValidationOperator]string{
 		DataValidationOperatorBetween:            "between",
 		DataValidationOperatorEqual:              "equal",

datavalidation_test.go

@@ -94,7 +94,7 @@ func TestDataValidationError(t *testing.T) {
 		t.Errorf("data validation error. Formula1 must be empty!")
 		return
 	}
-	assert.EqualError(t, err, ErrDataValidationFormulaLenth.Error())
+	assert.EqualError(t, err, ErrDataValidationFormulaLength.Error())
 	assert.EqualError(t, dvRange.SetRange(nil, 20, DataValidationTypeWhole, DataValidationOperatorBetween), ErrParameterInvalid.Error())
 	assert.EqualError(t, dvRange.SetRange(10, nil, DataValidationTypeWhole, DataValidationOperatorBetween), ErrParameterInvalid.Error())
 	assert.NoError(t, dvRange.SetRange(10, 20, DataValidationTypeWhole, DataValidationOperatorGreaterThan))
@@ -114,7 +114,7 @@ func TestDataValidationError(t *testing.T) {
 		err = dvRange.SetDropList(keys)
 		assert.Equal(t, prevFormula1, dvRange.Formula1,
 			"Formula1 should be unchanged for invalid input %v", keys)
-		assert.EqualError(t, err, ErrDataValidationFormulaLenth.Error())
+		assert.EqualError(t, err, ErrDataValidationFormulaLength.Error())
 	}
 	assert.NoError(t, f.AddDataValidation("Sheet1", dvRange))
 	assert.NoError(t, dvRange.SetRange(

errors.go

@@ -16,42 +16,50 @@ import (
 	"fmt"
 )
 
-// newInvalidColumnNameError defined the error message on receiving the invalid column name.
+// newInvalidColumnNameError defined the error message on receiving the
+// invalid column name.
 func newInvalidColumnNameError(col string) error {
 	return fmt.Errorf("invalid column name %q", col)
 }
 
-// newInvalidRowNumberError defined the error message on receiving the invalid row number.
+// newInvalidRowNumberError defined the error message on receiving the invalid
+// row number.
 func newInvalidRowNumberError(row int) error {
 	return fmt.Errorf("invalid row number %d", row)
 }
 
-// newInvalidCellNameError defined the error message on receiving the invalid cell name.
+// newInvalidCellNameError defined the error message on receiving the invalid
+// cell name.
 func newInvalidCellNameError(cell string) error {
 	return fmt.Errorf("invalid cell name %q", cell)
 }
 
-// newInvalidExcelDateError defined the error message on receiving the data with negative values.
+// newInvalidExcelDateError defined the error message on receiving the data
+// with negative values.
 func newInvalidExcelDateError(dateValue float64) error {
 	return fmt.Errorf("invalid date value %f, negative values are not supported", dateValue)
 }
 
-// newUnsupportChartType defined the error message on receiving the chart type are unsupported.
-func newUnsupportChartType(chartType string) error {
+// newUnsupportedChartType defined the error message on receiving the chart
+// type are unsupported.
+func newUnsupportedChartType(chartType string) error {
 	return fmt.Errorf("unsupported chart type %s", chartType)
 }
 
-// newUnzipSizeLimitError defined the error message on unzip size exceeds the limit.
+// newUnzipSizeLimitError defined the error message on unzip size exceeds the
+// limit.
 func newUnzipSizeLimitError(unzipSizeLimit int64) error {
 	return fmt.Errorf("unzip size exceeds the %d bytes limit", unzipSizeLimit)
 }
 
-// newInvalidStyleID defined the error message on receiving the invalid style ID.
+// newInvalidStyleID defined the error message on receiving the invalid style
+// ID.
 func newInvalidStyleID(styleID int) error {
 	return fmt.Errorf("invalid style ID %d, negative values are not supported", styleID)
 }
 
-// newFieldLengthError defined the error message on receiving the field length overflow.
+// newFieldLengthError defined the error message on receiving the field length
+// overflow.
 func newFieldLengthError(name string) error {
 	return fmt.Errorf("field %s must be less or equal than 255 characters", name)
 }
@@ -103,12 +111,18 @@ var (
 	ErrMaxFileNameLength = errors.New("file name length exceeds maximum limit")
 	// ErrEncrypt defined the error message on encryption spreadsheet.
 	ErrEncrypt = errors.New("not support encryption currently")
-	// ErrUnknownEncryptMechanism defined the error message on unsupport
+	// ErrUnknownEncryptMechanism defined the error message on unsupported
 	// encryption mechanism.
 	ErrUnknownEncryptMechanism = errors.New("unknown encryption mechanism")
-	// ErrUnsupportEncryptMechanism defined the error message on unsupport
+	// ErrUnsupportedEncryptMechanism defined the error message on unsupported
 	// encryption mechanism.
-	ErrUnsupportEncryptMechanism = errors.New("unsupport encryption mechanism")
+	ErrUnsupportedEncryptMechanism = errors.New("unsupported encryption mechanism")
+	// ErrUnsupportedHashAlgorithm defined the error message on unsupported
+	// hash algorithm.
+	ErrUnsupportedHashAlgorithm = errors.New("unsupported hash algorithm")
+	// ErrPasswordLengthInvalid defined the error message on invalid password
+	// length.
+	ErrPasswordLengthInvalid = errors.New("password length invalid")
 	// ErrParameterRequired defined the error message on receive the empty
 	// parameter.
 	ErrParameterRequired = errors.New("parameter is required")
@@ -131,11 +145,17 @@ var (
 	// ErrSheetIdx defined the error message on receive the invalid worksheet
 	// index.
 	ErrSheetIdx = errors.New("invalid worksheet index")
+	// ErrUnprotectSheet defined the error message on worksheet has set no
+	// protection.
+	ErrUnprotectSheet = errors.New("worksheet has set no protect")
+	// ErrUnprotectSheetPassword defined the error message on remove sheet
+	// protection with password verification failed.
+	ErrUnprotectSheetPassword = errors.New("worksheet protect password not match")
 	// ErrGroupSheets defined the error message on group sheets.
 	ErrGroupSheets = errors.New("group worksheet must contain an active worksheet")
-	// ErrDataValidationFormulaLenth defined the error message for receiving a
+	// ErrDataValidationFormulaLength defined the error message for receiving a
 	// data validation formula length that exceeds the limit.
-	ErrDataValidationFormulaLenth = errors.New("data validation must be 0-255 characters")
+	ErrDataValidationFormulaLength = errors.New("data validation must be 0-255 characters")
 	// ErrDataValidationRange defined the error message on set decimal range
 	// exceeds limit.
 	ErrDataValidationRange = errors.New("data validation range exceeds limit")
@@ -164,5 +184,5 @@ var (
 	ErrSparkline = errors.New("must have the same number of 'Location' and 'Range' parameters")
 	// ErrSparklineStyle defined the error message on receive the invalid
 	// sparkline Style parameters.
-	ErrSparklineStyle = errors.New("parameter 'Style' must betweent 0-35")
+	ErrSparklineStyle = errors.New("parameter 'Style' must between 0-35")
 )

excelize_test.go

@@ -1160,13 +1160,44 @@ func TestHSL(t *testing.T) {
 
 func TestProtectSheet(t *testing.T) {
 	f := NewFile()
-	assert.NoError(t, f.ProtectSheet("Sheet1", nil))
-	assert.NoError(t, f.ProtectSheet("Sheet1", &FormatSheetProtection{
+	sheetName := f.GetSheetName(0)
+	assert.NoError(t, f.ProtectSheet(sheetName, nil))
+	// Test protect worksheet with XOR hash algorithm
+	assert.NoError(t, f.ProtectSheet(sheetName, &FormatSheetProtection{
 		Password:      "password",
 		EditScenarios: false,
 	}))
-
+	ws, err := f.workSheetReader(sheetName)
+	assert.NoError(t, err)
+	assert.Equal(t, "83AF", ws.SheetProtection.Password)
 	assert.NoError(t, f.SaveAs(filepath.Join("test", "TestProtectSheet.xlsx")))
+	// Test protect worksheet with SHA-512 hash algorithm
+	assert.NoError(t, f.ProtectSheet(sheetName, &FormatSheetProtection{
+		AlgorithmName: "SHA-512",
+		Password:      "password",
+	}))
+	ws, err = f.workSheetReader(sheetName)
+	assert.NoError(t, err)
+	assert.Equal(t, 24, len(ws.SheetProtection.SaltValue))
+	assert.Equal(t, 88, len(ws.SheetProtection.HashValue))
+	assert.Equal(t, int(sheetProtectionSpinCount), ws.SheetProtection.SpinCount)
+	// Test remove sheet protection with an incorrect password
+	assert.EqualError(t, f.UnprotectSheet(sheetName, "wrongPassword"), ErrUnprotectSheetPassword.Error())
+	// Test remove sheet protection with password verification
+	assert.NoError(t, f.UnprotectSheet(sheetName, "password"))
+	// Test protect worksheet with empty password
+	assert.NoError(t, f.ProtectSheet(sheetName, &FormatSheetProtection{}))
+	assert.Equal(t, "", ws.SheetProtection.Password)
+	// Test protect worksheet with password exceeds the limit length
+	assert.EqualError(t, f.ProtectSheet(sheetName, &FormatSheetProtection{
+		AlgorithmName: "MD4",
+		Password:      strings.Repeat("s", MaxFieldLength+1),
+	}), ErrPasswordLengthInvalid.Error())
+	// Test protect worksheet with unsupported hash algorithm
+	assert.EqualError(t, f.ProtectSheet(sheetName, &FormatSheetProtection{
+		AlgorithmName: "RIPEMD-160",
+		Password:      "password",
+	}), ErrUnsupportedHashAlgorithm.Error())
 	// Test protect not exists worksheet.
 	assert.EqualError(t, f.ProtectSheet("SheetN", nil), "sheet SheetN is not exist")
 }
@@ -1176,12 +1207,30 @@ func TestUnprotectSheet(t *testing.T) {
 	if !assert.NoError(t, err) {
 		t.FailNow()
 	}
-	// Test unprotect not exists worksheet.
+	// Test remove protection on not exists worksheet.
 	assert.EqualError(t, f.UnprotectSheet("SheetN"), "sheet SheetN is not exist")
 
 	assert.NoError(t, f.UnprotectSheet("Sheet1"))
+	assert.EqualError(t, f.UnprotectSheet("Sheet1", "password"), ErrUnprotectSheet.Error())
 	assert.NoError(t, f.SaveAs(filepath.Join("test", "TestUnprotectSheet.xlsx")))
 	assert.NoError(t, f.Close())
+
+	f = NewFile()
+	sheetName := f.GetSheetName(0)
+	assert.NoError(t, f.ProtectSheet(sheetName, &FormatSheetProtection{Password: "password"}))
+	// Test remove sheet protection with an incorrect password
+	assert.EqualError(t, f.UnprotectSheet(sheetName, "wrongPassword"), ErrUnprotectSheetPassword.Error())
+	// Test remove sheet protection with password verification
+	assert.NoError(t, f.UnprotectSheet(sheetName, "password"))
+	// Test with invalid salt value
+	assert.NoError(t, f.ProtectSheet(sheetName, &FormatSheetProtection{
+		AlgorithmName: "SHA-512",
+		Password:      "password",
+	}))
+	ws, err := f.workSheetReader(sheetName)
+	assert.NoError(t, err)
+	ws.SheetProtection.SaltValue = "YWJjZA====="
+	assert.EqualError(t, f.UnprotectSheet(sheetName, "wrongPassword"), "illegal base64 data at input byte 8")
 }
 
 func TestSetDefaultTimeStyle(t *testing.T) {

pivotTable_test.go

@@ -222,7 +222,7 @@ func TestAddPivotTable(t *testing.T) {
 		PivotTableRange: "Sheet1!$G$2:$M$34",
 		Rows:            []PivotTableField{{Data: "Month", DefaultSubtotal: true}, {Data: "Year"}},
 		Columns:         []PivotTableField{{Data: "Type", DefaultSubtotal: true}},
-		Data:            []PivotTableField{{Data: "Sales", Subtotal: "-", Name: strings.Repeat("s", 256)}},
+		Data:            []PivotTableField{{Data: "Sales", Subtotal: "-", Name: strings.Repeat("s", MaxFieldLength+1)}},
 	}))
 
 	// Test adjust range with invalid range

sheet.go

@@ -1129,10 +1129,14 @@ func (f *File) SetHeaderFooter(sheet string, settings *FormatHeaderFooter) error
 }
 
 // ProtectSheet provides a function to prevent other users from accidentally
-// or deliberately changing, moving, or deleting data in a worksheet. For
-// example, protect Sheet1 with protection settings:
+// or deliberately changing, moving, or deleting data in a worksheet. The
+// optional field AlgorithmName specified hash algorithm, support XOR, MD4,
+// MD5, SHA1, SHA256, SHA384, and SHA512 currently, if no hash algorithm
+// specified, will be using the XOR algorithm as default. For example,
+// protect Sheet1 with protection settings:
 //
 //    err := f.ProtectSheet("Sheet1", &excelize.FormatSheetProtection{
+//        AlgorithmName: "SHA-512",
 //        Password:      "password",
 //        EditScenarios: false,
 //    })
@@ -1168,22 +1172,55 @@ func (f *File) ProtectSheet(sheet string, settings *FormatSheetProtection) error
 		Sort:                settings.Sort,
 	}
 	if settings.Password != "" {
+		if settings.AlgorithmName == "" {
 			ws.SheetProtection.Password = genSheetPasswd(settings.Password)
+			return err
+		}
+		hashValue, saltValue, err := genISOPasswdHash(settings.Password, settings.AlgorithmName, "", int(sheetProtectionSpinCount))
+		if err != nil {
+			return err
+		}
+		ws.SheetProtection.Password = ""
+		ws.SheetProtection.AlgorithmName = settings.AlgorithmName
+		ws.SheetProtection.SaltValue = saltValue
+		ws.SheetProtection.HashValue = hashValue
+		ws.SheetProtection.SpinCount = int(sheetProtectionSpinCount)
 	}
 	return err
 }
 
-// UnprotectSheet provides a function to unprotect an Excel worksheet.
-func (f *File) UnprotectSheet(sheet string) error {
+// UnprotectSheet provides a function to remove protection for a sheet,
+// specified the second optional password parameter to remove sheet
+// protection with password verification.
+func (f *File) UnprotectSheet(sheet string, password ...string) error {
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
 		return err
 	}
+	// password verification
+	if len(password) > 0 {
+		if ws.SheetProtection == nil {
+			return ErrUnprotectSheet
+		}
+		if ws.SheetProtection.AlgorithmName == "" && ws.SheetProtection.Password != genSheetPasswd(password[0]) {
+			return ErrUnprotectSheetPassword
+		}
+		if ws.SheetProtection.AlgorithmName != "" {
+			// check with given salt value
+			hashValue, _, err := genISOPasswdHash(password[0], ws.SheetProtection.AlgorithmName, ws.SheetProtection.SaltValue, ws.SheetProtection.SpinCount)
+			if err != nil {
+				return err
+			}
+			if ws.SheetProtection.HashValue != hashValue {
+				return ErrUnprotectSheetPassword
+			}
+		}
+	}
 	ws.SheetProtection = nil
 	return err
 }
 
-// trimSheetName provides a function to trim invaild characters by given worksheet
+// trimSheetName provides a function to trim invalid characters by given worksheet
 // name.
 func trimSheetName(name string) string {
 	if strings.ContainsAny(name, ":\\/?*[]") || utf8.RuneCountInString(name) > 31 {

xmlWorksheet.go

@@ -838,6 +838,7 @@ type formatConditional struct {
 
 // FormatSheetProtection directly maps the settings of worksheet protection.
 type FormatSheetProtection struct {
+	AlgorithmName       string
 	AutoFilter          bool
 	DeleteColumns       bool
 	DeleteRows          bool