Repository: gotenberg/gotenberg

Issue:
Feature request: Add permission passwords to PDF
Would it be possible to add permission passwords to the generated PDFs? 

https://helpx.adobe.com/acrobat/using/securing-pdfs-passwords.html

Discussion:
@janswist: I'm also interested in that feature! Any update if it's coming (or how to extract it from existing modules if they are already there) @gulien ? 

So far I found one from unoconv: https://github.com/unoconv/unoconv/issues/104@danielkorytek: @gulien Any update?@gulien: @janswist @gulien I'd like to implement it indeed, but I do not have enough free time on my side right now. In other words, I can only do minimal maintainability. 😕

Solution patch:
diff --git a/pkg/gotenberg/mocks.go b/pkg/gotenberg/mocks.go
index 458216f..faa8574 100644
--- a/pkg/gotenberg/mocks.go
+++ b/pkg/gotenberg/mocks.go
@@ -52,6 +52,7 @@ type PdfEngineMock struct {
 	ConvertMock       func(ctx context.Context, logger *zap.Logger, formats PdfFormats, inputPath, outputPath string) error
 	ReadMetadataMock  func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error)
 	WriteMetadataMock func(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error
+	EncryptMock       func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error
 }
 
 func (engine *PdfEngineMock) Merge(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
@@ -78,6 +79,10 @@ func (engine *PdfEngineMock) WriteMetadata(ctx context.Context, logger *zap.Logg
 	return engine.WriteMetadataMock(ctx, logger, metadata, inputPath)
 }
 
+func (engine *PdfEngineMock) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+	return engine.EncryptMock(ctx, logger, inputPath, userPassword, ownerPassword)
+}
+
 // PdfEngineProviderMock is a mock for the [PdfEngineProvider] interface.
 type PdfEngineProviderMock struct {
 	PdfEngineMock func() (PdfEngine, error)
diff --git a/pkg/gotenberg/pdfengine.go b/pkg/gotenberg/pdfengine.go
index bb9d43a..a27910e 100644
--- a/pkg/gotenberg/pdfengine.go
+++ b/pkg/gotenberg/pdfengine.go
@@ -23,6 +23,10 @@ var (
 	// ErrPdfEngineMetadataValueNotSupported is returned when a metadata value
 	// is not supported.
 	ErrPdfEngineMetadataValueNotSupported = errors.New("metadata value not supported")
+
+	// ErrPdfEncryptionNotSupported is returned when encryption
+	// is not supported by the PDF engine.
+	ErrPdfEncryptionNotSupported = errors.New("encryption not supported")
 )
 
 const (
@@ -113,6 +117,12 @@ type PdfEngine interface {
 
 	// WriteMetadata writes the metadata into a given PDF file.
 	WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error
+
+	// Encrypt adds password protection to a PDF file.
+	// The userPassword is required to open the document.
+	// The ownerPassword provides full access to the document.
+	// If the ownerPassword is empty, it defaults to the userPassword.
+	Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error
 }
 
 // PdfEngineProvider offers an interface to instantiate a [PdfEngine].
diff --git a/pkg/modules/chromium/routes.go b/pkg/modules/chromium/routes.go
index ee9c2ca..24c9996 100644
--- a/pkg/modules/chromium/routes.go
+++ b/pkg/modules/chromium/routes.go
@@ -332,6 +332,7 @@ func convertUrlRoute(chromium Api, engine gotenberg.PdfEngine) api.Route {
 			mode := pdfengines.FormDataPdfSplitMode(form, false)
 			pdfFormats := pdfengines.FormDataPdfFormats(form)
 			metadata := pdfengines.FormDataPdfMetadata(form, false)
+			userPassword, ownerPassword := pdfengines.FormDataPdfEncrypt(form)
 
 			var url string
 			err := form.
@@ -341,7 +342,7 @@ func convertUrlRoute(chromium Api, engine gotenberg.PdfEngine) api.Route {
 				return fmt.Errorf("validate form data: %w", err)
 			}
 
-			err = convertUrl(ctx, chromium, engine, url, options, mode, pdfFormats, metadata)
+			err = convertUrl(ctx, chromium, engine, url, options, mode, pdfFormats, metadata, userPassword, ownerPassword)
 			if err != nil {
 				return fmt.Errorf("convert URL to PDF: %w", err)
 			}
@@ -393,6 +394,7 @@ func convertHtmlRoute(chromium Api, engine gotenberg.PdfEngine) api.Route {
 			mode := pdfengines.FormDataPdfSplitMode(form, false)
 			pdfFormats := pdfengines.FormDataPdfFormats(form)
 			metadata := pdfengines.FormDataPdfMetadata(form, false)
+			userPassword, ownerPassword := pdfengines.FormDataPdfEncrypt(form)
 
 			var inputPath string
 			err := form.
@@ -403,7 +405,7 @@ func convertHtmlRoute(chromium Api, engine gotenberg.PdfEngine) api.Route {
 			}
 
 			url := fmt.Sprintf("file://%s", inputPath)
-			err = convertUrl(ctx, chromium, engine, url, options, mode, pdfFormats, metadata)
+			err = convertUrl(ctx, chromium, engine, url, options, mode, pdfFormats, metadata, userPassword, ownerPassword)
 			if err != nil {
 				return fmt.Errorf("convert HTML to PDF: %w", err)
 			}
@@ -456,6 +458,7 @@ func convertMarkdownRoute(chromium Api, engine gotenberg.PdfEngine) api.Route {
 			mode := pdfengines.FormDataPdfSplitMode(form, false)
 			pdfFormats := pdfengines.FormDataPdfFormats(form)
 			metadata := pdfengines.FormDataPdfMetadata(form, false)
+			userPassword, ownerPassword := pdfengines.FormDataPdfEncrypt(form)
 
 			var (
 				inputPath     string
@@ -475,7 +478,7 @@ func convertMarkdownRoute(chromium Api, engine gotenberg.PdfEngine) api.Route {
 				return fmt.Errorf("transform markdown file(s) to HTML: %w", err)
 			}
 
-			err = convertUrl(ctx, chromium, engine, url, options, mode, pdfFormats, metadata)
+			err = convertUrl(ctx, chromium, engine, url, options, mode, pdfFormats, metadata, userPassword, ownerPassword)
 			if err != nil {
 				return fmt.Errorf("convert markdown to PDF: %w", err)
 			}
@@ -599,7 +602,7 @@ func markdownToHtml(ctx *api.Context, inputPath string, markdownPaths []string)
 	return fmt.Sprintf("file://%s", inputPath), nil
 }
 
-func convertUrl(ctx *api.Context, chromium Api, engine gotenberg.PdfEngine, url string, options PdfOptions, mode gotenberg.SplitMode, pdfFormats gotenberg.PdfFormats, metadata map[string]interface{}) error {
+func convertUrl(ctx *api.Context, chromium Api, engine gotenberg.PdfEngine, url string, options PdfOptions, mode gotenberg.SplitMode, pdfFormats gotenberg.PdfFormats, metadata map[string]interface{}, userPassword, ownerPassword string) error {
 	outputPath := ctx.GeneratePath(".pdf")
 	// See https://github.com/gotenberg/gotenberg/issues/1130.
 	filename := ctx.OutputFilename(outputPath)
@@ -656,6 +659,11 @@ func convertUrl(ctx *api.Context, chromium Api, engine gotenberg.PdfEngine, url
 		return fmt.Errorf("write metadata: %w", err)
 	}
 
+	err = pdfengines.EncryptPdfStub(ctx, engine, userPassword, ownerPassword, convertOutputPaths)
+	if err != nil {
+		return fmt.Errorf("encrypt PDFs: %w", err)
+	}
+
 	zeroValuedSplitMode := gotenberg.SplitMode{}
 	zeroValuedPdfFormats := gotenberg.PdfFormats{}
 	if mode != zeroValuedSplitMode && pdfFormats != zeroValuedPdfFormats {
diff --git a/pkg/modules/exiftool/exiftool.go b/pkg/modules/exiftool/exiftool.go
index 6127035..ae33e88 100644
--- a/pkg/modules/exiftool/exiftool.go
+++ b/pkg/modules/exiftool/exiftool.go
@@ -176,6 +176,11 @@ func (engine *ExifTool) WriteMetadata(ctx context.Context, logger *zap.Logger, m
 	return nil
 }
 
+// Encrypt is not available in this implementation.
+func (engine *ExifTool) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+	return fmt.Errorf("encrypt PDF using ExifTool: %w", gotenberg.ErrPdfEncryptionNotSupported)
+}
+
 // Interface guards.
 var (
 	_ gotenberg.Module      = (*ExifTool)(nil)
diff --git a/pkg/modules/libreoffice/pdfengine/pdfengine.go b/pkg/modules/libreoffice/pdfengine/pdfengine.go
index 94dfc4f..e47d9b8 100644
--- a/pkg/modules/libreoffice/pdfengine/pdfengine.go
+++ b/pkg/modules/libreoffice/pdfengine/pdfengine.go
@@ -91,6 +91,11 @@ func (engine *LibreOfficePdfEngine) WriteMetadata(ctx context.Context, logger *z
 	return fmt.Errorf("write PDF metadata with LibreOffice: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
+// Encrypt is not available in this implementation.
+func (engine *LibreOfficePdfEngine) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+	return fmt.Errorf("encrypt PDF using LibreOffice: %w", gotenberg.ErrPdfEngineMethodNotSupported)
+}
+
 // Interface guards.
 var (
 	_ gotenberg.Module      = (*LibreOfficePdfEngine)(nil)
diff --git a/pkg/modules/libreoffice/routes.go b/pkg/modules/libreoffice/routes.go
index ceaf282..748f6a7 100644
--- a/pkg/modules/libreoffice/routes.go
+++ b/pkg/modules/libreoffice/routes.go
@@ -30,6 +30,7 @@ func convertRoute(libreOffice libreofficeapi.Uno, engine gotenberg.PdfEngine) ap
 			splitMode := pdfengines.FormDataPdfSplitMode(form, false)
 			pdfFormats := pdfengines.FormDataPdfFormats(form)
 			metadata := pdfengines.FormDataPdfMetadata(form, false)
+			userPassword, ownerPassword := pdfengines.FormDataPdfEncrypt(form)
 
 			zeroValuedSplitMode := gotenberg.SplitMode{}
 
@@ -277,6 +278,11 @@ func convertRoute(libreOffice libreofficeapi.Uno, engine gotenberg.PdfEngine) ap
 				}
 			}
 
+			err = pdfengines.EncryptPdfStub(ctx, engine, userPassword, ownerPassword, outputPaths)
+			if err != nil {
+				return fmt.Errorf("encrypt PDFs: %w", err)
+			}
+
 			err = ctx.AddOutputPaths(outputPaths...)
 			if err != nil {
 				return fmt.Errorf("add output paths: %w", err)
diff --git a/pkg/modules/pdfcpu/pdfcpu.go b/pkg/modules/pdfcpu/pdfcpu.go
index 50b7acb..d681f95 100644
--- a/pkg/modules/pdfcpu/pdfcpu.go
+++ b/pkg/modules/pdfcpu/pdfcpu.go
@@ -171,6 +171,38 @@ func (engine *PdfCpu) WriteMetadata(ctx context.Context, logger *zap.Logger, met
 	return fmt.Errorf("write PDF metadata with pdfcpu: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
+// Encrypt adds password protection to a PDF file using pdfcpu.
+func (engine *PdfCpu) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+	if userPassword == "" {
+		return errors.New("user password cannot be empty")
+	}
+
+	// If owner password is not provided, use the user password as owner password
+	if ownerPassword == "" {
+		ownerPassword = userPassword
+	}
+
+	var args []string
+	args = append(args, "encrypt")
+	args = append(args, "-mode", "aes") // Use AES encryption
+	args = append(args, "-upw", userPassword)
+	args = append(args, "-opw", ownerPassword)
+	args = append(args, "-perm", "all") // Grant all permissions with owner password
+	args = append(args, inputPath, inputPath)
+
+	cmd, err := gotenberg.CommandContext(ctx, logger, engine.binPath, args...)
+	if err != nil {
+		return fmt.Errorf("create command: %w", err)
+	}
+
+	_, err = cmd.Exec()
+	if err != nil {
+		return fmt.Errorf("encrypt PDF with pdfcpu: %w", err)
+	}
+
+	return nil
+}
+
 // Interface guards.
 var (
 	_ gotenberg.Module      = (*PdfCpu)(nil)
diff --git a/pkg/modules/pdfengines/multi.go b/pkg/modules/pdfengines/multi.go
index 4347a0d..640c776 100644
--- a/pkg/modules/pdfengines/multi.go
+++ b/pkg/modules/pdfengines/multi.go
@@ -18,6 +18,7 @@ type multiPdfEngines struct {
 	convertEngines       []gotenberg.PdfEngine
 	readMetadataEngines  []gotenberg.PdfEngine
 	writeMetadataEngines []gotenberg.PdfEngine
+	passwordEngines      []gotenberg.PdfEngine
 }
 
 func newMultiPdfEngines(
@@ -26,7 +27,8 @@ func newMultiPdfEngines(
 	flattenEngines,
 	convertEngines,
 	readMetadataEngines,
-	writeMetadataEngines []gotenberg.PdfEngine,
+	writeMetadataEngines,
+	passwordEngines []gotenberg.PdfEngine,
 ) *multiPdfEngines {
 	return &multiPdfEngines{
 		mergeEngines:         mergeEngines,
@@ -35,6 +37,7 @@ func newMultiPdfEngines(
 		convertEngines:       convertEngines,
 		readMetadataEngines:  readMetadataEngines,
 		writeMetadataEngines: writeMetadataEngines,
+		passwordEngines:      passwordEngines,
 	}
 }
 
@@ -206,6 +209,31 @@ func (multi *multiPdfEngines) WriteMetadata(ctx context.Context, logger *zap.Log
 	return fmt.Errorf("write PDF metadata with multi PDF engines: %w", err)
 }
 
+// Encrypt adds password protection to a PDF file using the first available engine
+// that supports password protection.
+func (multi *multiPdfEngines) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+	var err error
+	errChan := make(chan error, 1)
+
+	for _, engine := range multi.passwordEngines {
+		go func(engine gotenberg.PdfEngine) {
+			errChan <- engine.Encrypt(ctx, logger, inputPath, userPassword, ownerPassword)
+		}(engine)
+
+		select {
+		case protectErr := <-errChan:
+			errored := multierr.AppendInto(&err, protectErr)
+			if !errored {
+				return nil
+			}
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+
+	return fmt.Errorf("encrypt PDF using multi PDF engines: %w", err)
+}
+
 // Interface guards.
 var (
 	_ gotenberg.PdfEngine = (*multiPdfEngines)(nil)
diff --git a/pkg/modules/pdfengines/pdfengines.go b/pkg/modules/pdfengines/pdfengines.go
index c73ea85..48f1050 100644
--- a/pkg/modules/pdfengines/pdfengines.go
+++ b/pkg/modules/pdfengines/pdfengines.go
@@ -33,6 +33,7 @@ type PdfEngines struct {
 	convertNames       []string
 	readMetadataNames  []string
 	writeMetadataNames []string
+	encryptNames       []string
 	engines            []gotenberg.PdfEngine
 	disableRoutes      bool
 }
@@ -49,6 +50,7 @@ func (mod *PdfEngines) Descriptor() gotenberg.ModuleDescriptor {
 			fs.StringSlice("pdfengines-convert-engines", []string{"libreoffice-pdfengine"}, "Set the PDF engines and their order for the convert feature - empty means all")
 			fs.StringSlice("pdfengines-read-metadata-engines", []string{"exiftool"}, "Set the PDF engines and their order for the read metadata feature - empty means all")
 			fs.StringSlice("pdfengines-write-metadata-engines", []string{"exiftool"}, "Set the PDF engines and their order for the write metadata feature - empty means all")
+			fs.StringSlice("pdfengines-encrypt-engines", []string{"qpdf", "pdftk", "pdfcpu"}, "Set the PDF engines and their order for the password protection feature - empty means all")
 			fs.Bool("pdfengines-disable-routes", false, "Disable the routes")
 
 			// Deprecated flags.
@@ -74,6 +76,7 @@ func (mod *PdfEngines) Provision(ctx *gotenberg.Context) error {
 	convertNames := flags.MustStringSlice("pdfengines-convert-engines")
 	readMetadataNames := flags.MustStringSlice("pdfengines-read-metadata-engines")
 	writeMetadataNames := flags.MustStringSlice("pdfengines-write-metadata-engines")
+	encryptNames := flags.MustStringSlice("pdfengines-encrypt-engines")
 	mod.disableRoutes = flags.MustBool("pdfengines-disable-routes")
 
 	engines, err := ctx.Modules(new(gotenberg.PdfEngine))
@@ -130,6 +133,11 @@ func (mod *PdfEngines) Provision(ctx *gotenberg.Context) error {
 		mod.writeMetadataNames = writeMetadataNames
 	}
 
+	mod.encryptNames = defaultNames
+	if len(encryptNames) > 0 {
+		mod.encryptNames = encryptNames
+	}
+
 	return nil
 }
 
@@ -183,6 +191,7 @@ func (mod *PdfEngines) Validate() error {
 	findNonExistingEngines(mod.convertNames)
 	findNonExistingEngines(mod.readMetadataNames)
 	findNonExistingEngines(mod.writeMetadataNames)
+	findNonExistingEngines(mod.encryptNames)
 
 	if len(nonExistingEngines) == 0 {
 		return nil
@@ -201,6 +210,7 @@ func (mod *PdfEngines) SystemMessages() []string {
 		fmt.Sprintf("convert engines - %s", strings.Join(mod.convertNames[:], " ")),
 		fmt.Sprintf("read metadata engines - %s", strings.Join(mod.readMetadataNames[:], " ")),
 		fmt.Sprintf("write metadata engines - %s", strings.Join(mod.writeMetadataNames[:], " ")),
+		fmt.Sprintf("password protection engines - %s", strings.Join(mod.encryptNames[:], " ")),
 	}
 }
 
@@ -227,6 +237,7 @@ func (mod *PdfEngines) PdfEngine() (gotenberg.PdfEngine, error) {
 		engines(mod.convertNames),
 		engines(mod.readMetadataNames),
 		engines(mod.writeMetadataNames),
+		engines(mod.encryptNames),
 	), nil
 }
 
@@ -250,6 +261,7 @@ func (mod *PdfEngines) Routes() ([]api.Route, error) {
 		convertRoute(engine),
 		readMetadataRoute(engine),
 		writeMetadataRoute(engine),
+		encryptRoute(engine),
 	}, nil
 }
 
diff --git a/pkg/modules/pdfengines/routes.go b/pkg/modules/pdfengines/routes.go
index a316142..262a18a 100644
--- a/pkg/modules/pdfengines/routes.go
+++ b/pkg/modules/pdfengines/routes.go
@@ -254,6 +254,29 @@ func WriteMetadataStub(ctx *api.Context, engine gotenberg.PdfEngine, metadata ma
 	return nil
 }
 
+// EncryptPdfStub adds password protection to PDF files.
+// FormDataPdfEncrypt extracts encryption parameters from form data.
+func FormDataPdfEncrypt(form *api.FormData) (userPassword, ownerPassword string) {
+	form.String("userPassword", &userPassword, "")
+	form.String("ownerPassword", &ownerPassword, "")
+	return userPassword, ownerPassword
+}
+
+func EncryptPdfStub(ctx *api.Context, engine gotenberg.PdfEngine, userPassword, ownerPassword string, inputPaths []string) error {
+	if userPassword == "" {
+		return nil
+	}
+
+	for _, inputPath := range inputPaths {
+		err := engine.Encrypt(ctx, ctx.Log(), inputPath, userPassword, ownerPassword)
+		if err != nil {
+			return fmt.Errorf("encrypt PDF '%s': %w", inputPath, err)
+		}
+	}
+
+	return nil
+}
+
 // mergeRoute returns an [api.Route] which can merge PDFs.
 func mergeRoute(engine gotenberg.PdfEngine) api.Route {
 	return api.Route{
@@ -266,6 +289,7 @@ func mergeRoute(engine gotenberg.PdfEngine) api.Route {
 			form := ctx.FormData()
 			pdfFormats := FormDataPdfFormats(form)
 			metadata := FormDataPdfMetadata(form, false)
+			userPassword, ownerPassword := FormDataPdfEncrypt(form)
 
 			var inputPaths []string
 			var flatten bool
@@ -300,6 +324,11 @@ func mergeRoute(engine gotenberg.PdfEngine) api.Route {
 				}
 			}
 
+			err = EncryptPdfStub(ctx, engine, userPassword, ownerPassword, outputPaths)
+			if err != nil {
+				return fmt.Errorf("encrypt PDFs: %w", err)
+			}
+
 			err = ctx.AddOutputPaths(outputPaths...)
 			if err != nil {
 				return fmt.Errorf("add output paths: %w", err)
@@ -323,6 +352,7 @@ func splitRoute(engine gotenberg.PdfEngine) api.Route {
 			mode := FormDataPdfSplitMode(form, true)
 			pdfFormats := FormDataPdfFormats(form)
 			metadata := FormDataPdfMetadata(form, false)
+			userPassword, ownerPassword := FormDataPdfEncrypt(form)
 
 			var inputPaths []string
 			var flatten bool
@@ -356,6 +386,11 @@ func splitRoute(engine gotenberg.PdfEngine) api.Route {
 				}
 			}
 
+			err = EncryptPdfStub(ctx, engine, userPassword, ownerPassword, convertOutputPaths)
+			if err != nil {
+				return fmt.Errorf("encrypt PDFs: %w", err)
+			}
+
 			zeroValuedSplitMode := gotenberg.SplitMode{}
 			zeroValuedPdfFormats := gotenberg.PdfFormats{}
 			if mode != zeroValuedSplitMode && pdfFormats != zeroValuedPdfFormats {
@@ -424,6 +459,7 @@ func convertRoute(engine gotenberg.PdfEngine) api.Route {
 
 			form := ctx.FormData()
 			pdfFormats := FormDataPdfFormats(form)
+			userPassword, ownerPassword := FormDataPdfEncrypt(form)
 
 			var inputPaths []string
 			err := form.
@@ -456,11 +492,15 @@ func convertRoute(engine gotenberg.PdfEngine) api.Route {
 					if err != nil {
 						return fmt.Errorf("rename output path: %w", err)
 					}
-
 					outputPaths[i] = inputPath
 				}
 			}
 
+			err = EncryptPdfStub(ctx, engine, userPassword, ownerPassword, outputPaths)
+			if err != nil {
+				return fmt.Errorf("encrypt PDFs: %w", err)
+			}
+
 			err = ctx.AddOutputPaths(outputPaths...)
 			if err != nil {
 				return fmt.Errorf("add output paths: %w", err)
@@ -548,3 +588,41 @@ func writeMetadataRoute(engine gotenberg.PdfEngine) api.Route {
 		},
 	}
 }
+
+// encryptRoute returns an [api.Route] which can add password protection to PDFs.
+func encryptRoute(engine gotenberg.PdfEngine) api.Route {
+	return api.Route{
+		Method:      http.MethodPost,
+		Path:        "/forms/pdfengines/encrypt",
+		IsMultipart: true,
+		Handler: func(c echo.Context) error {
+			ctx := c.Get("context").(*api.Context)
+
+			form := ctx.FormData()
+
+			var inputPaths []string
+			var userPassword string
+			var ownerPassword string
+			err := form.
+				MandatoryPaths([]string{".pdf"}, &inputPaths).
+				MandatoryString("userPassword", &userPassword).
+				String("ownerPassword", &ownerPassword, "").
+				Validate()
+			if err != nil {
+				return fmt.Errorf("validate form data: %w", err)
+			}
+
+			err = EncryptPdfStub(ctx, engine, userPassword, ownerPassword, inputPaths)
+			if err != nil {
+				return fmt.Errorf("encrypt PDFs: %w", err)
+			}
+
+			err = ctx.AddOutputPaths(inputPaths...)
+			if err != nil {
+				return fmt.Errorf("add output paths: %w", err)
+			}
+
+			return nil
+		},
+	}
+}
diff --git a/pkg/modules/pdftk/pdftk.go b/pkg/modules/pdftk/pdftk.go
index b2831dc..755d172 100644
--- a/pkg/modules/pdftk/pdftk.go
+++ b/pkg/modules/pdftk/pdftk.go
@@ -145,6 +145,43 @@ func (engine *PdfTk) WriteMetadata(ctx context.Context, logger *zap.Logger, meta
 	return fmt.Errorf("write PDF metadata with PDFtk: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
+// Encrypt adds password protection to a PDF file using PDFtk.
+func (engine *PdfTk) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+	if userPassword == "" {
+		return errors.New("user password cannot be empty")
+	}
+
+	// If owner password is not provided, use the user password as owner password
+	if ownerPassword == "" {
+		ownerPassword = userPassword
+	}
+
+	var args []string
+	args = append(args, inputPath)
+	args = append(args, "output", inputPath)
+	args = append(args, "encrypt_128bit")
+
+	if userPassword != "" {
+		args = append(args, "user_pw", userPassword)
+	}
+
+	if ownerPassword != "" {
+		args = append(args, "owner_pw", ownerPassword)
+	}
+
+	cmd, err := gotenberg.CommandContext(ctx, logger, engine.binPath, args...)
+	if err != nil {
+		return fmt.Errorf("create command: %w", err)
+	}
+
+	_, err = cmd.Exec()
+	if err != nil {
+		return fmt.Errorf("encrypt PDF with PDFtk: %w", err)
+	}
+
+	return nil
+}
+
 // Interface guards.
 var (
 	_ gotenberg.Module      = (*PdfTk)(nil)
diff --git a/pkg/modules/qpdf/qpdf.go b/pkg/modules/qpdf/qpdf.go
index 7a65991..8d2cd1f 100644
--- a/pkg/modules/qpdf/qpdf.go
+++ b/pkg/modules/qpdf/qpdf.go
@@ -172,6 +172,37 @@ func (engine *QPdf) WriteMetadata(ctx context.Context, logger *zap.Logger, metad
 	return fmt.Errorf("write PDF metadata with QPDF: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
+// Encrypt adds password protection to a PDF file using QPDF.
+func (engine *QPdf) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+	if userPassword == "" {
+		return errors.New("user password cannot be empty")
+	}
+
+	// If owner password is not provided, use the user password as owner password
+	if ownerPassword == "" {
+		ownerPassword = userPassword
+	}
+
+	// QPDF command to encrypt a PDF
+	var args []string
+	args = append(args, inputPath)
+	args = append(args, engine.globalArgs...)
+	args = append(args, "--encrypt", userPassword, ownerPassword, "256", "--use-aes=y", "--")
+	args = append(args, inputPath)
+
+	cmd, err := gotenberg.CommandContext(ctx, logger, engine.binPath, args...)
+	if err != nil {
+		return fmt.Errorf("create command: %w", err)
+	}
+
+	_, err = cmd.Exec()
+	if err != nil {
+		return fmt.Errorf("encrypt PDF with QPDF: %w", err)
+	}
+
+	return nil
+}
+
 var (
 	_ gotenberg.Module      = (*QPdf)(nil)
 	_ gotenberg.Provisioner = (*QPdf)(nil)



Test patch:
diff --git a/pkg/modules/pdfengines/multi_test.go b/pkg/modules/pdfengines/multi_test.go
index f5d5b21..496a440 100644
--- a/pkg/modules/pdfengines/multi_test.go
+++ b/pkg/modules/pdfengines/multi_test.go
@@ -103,6 +103,97 @@ func TestMultiPdfEngines_Merge(t *testing.T) {
 	}
 }
 
+func TestMultiPdfEngines_Encrypt(t *testing.T) {
+	for _, tc := range []struct {
+		scenario    string
+		engine      *multiPdfEngines
+		ctx         context.Context
+		expectError bool
+	}{
+		{
+			scenario: "nominal behavior",
+			engine: &multiPdfEngines{
+				passwordEngines: []gotenberg.PdfEngine{
+					&gotenberg.PdfEngineMock{
+						EncryptMock: func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+							return nil
+						},
+					},
+				},
+			},
+			ctx: context.Background(),
+		},
+		{
+			scenario: "at least one engine does not return an error",
+			engine: &multiPdfEngines{
+				passwordEngines: []gotenberg.PdfEngine{
+					&gotenberg.PdfEngineMock{
+						EncryptMock: func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+							return errors.New("foo")
+						},
+					},
+					&gotenberg.PdfEngineMock{
+						EncryptMock: func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+							return nil
+						},
+					},
+				},
+			},
+			ctx: context.Background(),
+		},
+		{
+			scenario: "all engines return an error",
+			engine: &multiPdfEngines{
+				passwordEngines: []gotenberg.PdfEngine{
+					&gotenberg.PdfEngineMock{
+						EncryptMock: func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+							return errors.New("foo")
+						},
+					},
+					&gotenberg.PdfEngineMock{
+						EncryptMock: func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+							return errors.New("foo")
+						},
+					},
+				},
+			},
+			ctx:         context.Background(),
+			expectError: true,
+		},
+		{
+			scenario: "context expired",
+			engine: &multiPdfEngines{
+				passwordEngines: []gotenberg.PdfEngine{
+					&gotenberg.PdfEngineMock{
+						EncryptMock: func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
+							return nil
+						},
+					},
+				},
+			},
+			ctx: func() context.Context {
+				ctx, cancel := context.WithCancel(context.Background())
+				cancel()
+
+				return ctx
+			}(),
+			expectError: true,
+		},
+	} {
+		t.Run(tc.scenario, func(t *testing.T) {
+			err := tc.engine.Encrypt(tc.ctx, zap.NewNop(), "", "", "")
+
+			if !tc.expectError && err != nil {
+				t.Fatalf("expected no error but got: %v", err)
+			}
+
+			if tc.expectError && err == nil {
+				t.Fatal("expected error but got none")
+			}
+		})
+	}
+}
+
 func TestMultiPdfEngines_Split(t *testing.T) {
 	for _, tc := range []struct {
 		scenario    string
diff --git a/test/integration/features/chromium_convert_html.feature b/test/integration/features/chromium_convert_html.feature
index ab93e34..a45fc04 100644
--- a/test/integration/features/chromium_convert_html.feature
+++ b/test/integration/features/chromium_convert_html.feature
@@ -918,3 +918,75 @@ Feature: /forms/chromium/convert/html
       | files | testdata/page-1-html/index.html | file |
     Then the response status code should be 200
     Then the response header "Content-Type" should be "application/pdf"
+
+  Scenario: POST /forms/chromium/convert/html with encryption (user password only)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                     | testdata/page-1-html/index.html | file   |
+      | userPassword              | test123                         | field  |
+      | Gotenberg-Output-Filename | encrypted                       | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/chromium/convert/html with encryption (user and owner passwords)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                     | testdata/page-1-html/index.html | file   |
+      | userPassword              | user123                         | field  |
+      | ownerPassword             | owner456                        | field  |
+      | Gotenberg-Output-Filename | encrypted                       | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/chromium/convert/html with encryption and PDF/A conversion
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                     | testdata/page-1-html/index.html | file   |
+      | userPassword              | test123                         | field  |
+      | pdfa                      | PDF/A-1a                        | field  |
+      | Gotenberg-Output-Filename | encrypted                       | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/chromium/convert/html with encryption and page splitting
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                     | testdata/pages-12-html/index.html | file   |
+      | userPassword              | test123                           | field  |
+      | splitMode                 | intervals                         | field  |
+      | splitSpan                 | 5                                 | field  |
+      | Gotenberg-Output-Filename | encrypted                         | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be the following file(s) in the response:
+      | encrypted.zip |
+    Then the "encrypted.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/chromium/convert/html without encryption (empty password)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                     | testdata/page-1-html/index.html | file   |
+      | userPassword              |                                 | field  |
+      | Gotenberg-Output-Filename | unencrypted                     | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | unencrypted.pdf |
+    Then the "unencrypted.pdf" PDF should NOT be encrypted
+    Then the "unencrypted.pdf" PDF should have 1 page(s)
diff --git a/test/integration/features/chromium_convert_markdown.feature b/test/integration/features/chromium_convert_markdown.feature
index b8d84c2..2089258 100644
--- a/test/integration/features/chromium_convert_markdown.feature
+++ b/test/integration/features/chromium_convert_markdown.feature
@@ -1049,3 +1049,81 @@ Feature: /forms/chromium/convert/markdown
       | files | testdata/page-1-markdown/page_1.md  | file |
     Then the response status code should be 200
     Then the response header "Content-Type" should be "application/pdf"
+
+  Scenario: POST /forms/chromium/convert/markdown with encryption (user password only)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/markdown" endpoint with the following form data and header(s):
+      | files                     | testdata/page-1-markdown/index.html | file   |
+      | files                     | testdata/page-1-markdown/page_1.md  | file   |
+      | userPassword              | test123                             | field  |
+      | Gotenberg-Output-Filename | encrypted                           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/chromium/convert/markdown with encryption (user and owner passwords)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/markdown" endpoint with the following form data and header(s):
+      | files                     | testdata/page-1-markdown/index.html | file   |
+      | files                     | testdata/page-1-markdown/page_1.md  | file   |
+      | userPassword              | user123                             | field  |
+      | ownerPassword             | owner456                            | field  |
+      | Gotenberg-Output-Filename | encrypted                           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/chromium/convert/markdown with encryption and PDF/A conversion
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/markdown" endpoint with the following form data and header(s):
+      | files                     | testdata/page-1-markdown/index.html | file   |
+      | files                     | testdata/page-1-markdown/page_1.md  | file   |
+      | userPassword              | test123                             | field  |
+      | pdfa                      | PDF/A-1a                            | field  |
+      | Gotenberg-Output-Filename | encrypted                           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/chromium/convert/markdown with encryption and page splitting
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/markdown" endpoint with the following form data and header(s):
+      | files                     | testdata/pages-12-markdown/index.html | file   |
+      | files                     | testdata/pages-12-markdown/page_1.md  | file   |
+      | files                     | testdata/pages-12-markdown/page_2.md  | file   |
+      | userPassword              | test123                               | field  |
+      | splitMode                 | intervals                             | field  |
+      | splitSpan                 | 5                                     | field  |
+      | Gotenberg-Output-Filename | encrypted                             | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be the following file(s) in the response:
+      | encrypted.zip |
+    Then the "encrypted.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/chromium/convert/markdown without encryption (empty password)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/markdown" endpoint with the following form data and header(s):
+      | files                     | testdata/page-1-markdown/index.html | file   |
+      | files                     | testdata/page-1-markdown/page_1.md  | file   |
+      | userPassword              |                                     | field  |
+      | Gotenberg-Output-Filename | unencrypted                         | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | unencrypted.pdf |
+    Then the "unencrypted.pdf" PDF should NOT be encrypted
+    Then the "unencrypted.pdf" PDF should have 1 page(s)
diff --git a/test/integration/features/chromium_convert_url.feature b/test/integration/features/chromium_convert_url.feature
index 4c16dc2..34e437a 100644
--- a/test/integration/features/chromium_convert_url.feature
+++ b/test/integration/features/chromium_convert_url.feature
@@ -997,3 +997,80 @@ Feature: /forms/chromium/convert/url
       | url | http://host.docker.internal:%d/html/testdata/page-1-html/index.html | field |
     Then the response status code should be 200
     Then the response header "Content-Type" should be "application/pdf"
+
+  Scenario: POST /forms/chromium/convert/url with encryption (user password only)
+    Given I have a default Gotenberg container
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                       | http://host.docker.internal:%d/html/testdata/page-1-html/index.html | field  |
+      | userPassword              | test123                                                             | field  |
+      | Gotenberg-Output-Filename | encrypted                                                           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/chromium/convert/url with encryption (user and owner passwords)
+    Given I have a default Gotenberg container
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                       | http://host.docker.internal:%d/html/testdata/page-1-html/index.html | field  |
+      | userPassword              | user123                                                             | field  |
+      | ownerPassword             | owner456                                                            | field  |
+      | Gotenberg-Output-Filename | encrypted                                                           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/chromium/convert/url with encryption and PDF/A conversion
+    Given I have a default Gotenberg container
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                       | http://host.docker.internal:%d/html/testdata/page-1-html/index.html | field  |
+      | userPassword              | test123                                                             | field  |
+      | pdfa                      | PDF/A-1a                                                            | field  |
+      | Gotenberg-Output-Filename | encrypted                                                           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/chromium/convert/url with encryption and page splitting
+    Given I have a default Gotenberg container
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                       | http://host.docker.internal:%d/html/testdata/pages-12-html/index.html | field  |
+      | userPassword              | test123                                                               | field  |
+      | splitMode                 | intervals                                                             | field  |
+      | splitSpan                 | 5                                                                     | field  |
+      | Gotenberg-Output-Filename | encrypted                                                             | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be the following file(s) in the response:
+      | encrypted.zip |
+    Then the "encrypted.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/chromium/convert/url without encryption (empty password)
+    Given I have a default Gotenberg container
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                       | http://host.docker.internal:%d/html/testdata/page-1-html/index.html | field  |
+      | userPassword              |                                                                     | field  |
+      | Gotenberg-Output-Filename | unencrypted                                                         | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | unencrypted.pdf |
+    Then the "unencrypted.pdf" PDF should NOT be encrypted
+    Then the "unencrypted.pdf" PDF should have 1 page(s)
diff --git a/test/integration/features/libreoffice_convert.feature b/test/integration/features/libreoffice_convert.feature
index 8a96a93..15ebb29 100644
--- a/test/integration/features/libreoffice_convert.feature
+++ b/test/integration/features/libreoffice_convert.feature
@@ -631,3 +631,90 @@ Feature: /forms/libreoffice/convert
       | files | testdata/page_1.docx | file |
     Then the response status code should be 200
     Then the response header "Content-Type" should be "application/pdf"
+
+  Scenario: POST /forms/libreoffice/convert with encryption (user password only)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/libreoffice/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.docx | file   |
+      | userPassword              | test123              | field  |
+      | Gotenberg-Output-Filename | encrypted            | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/libreoffice/convert with encryption (user and owner passwords)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/libreoffice/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.docx | file   |
+      | userPassword              | user123              | field  |
+      | ownerPassword             | owner456             | field  |
+      | Gotenberg-Output-Filename | encrypted            | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/libreoffice/convert with encryption and PDF/A conversion
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/libreoffice/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.docx | file   |
+      | userPassword              | test123              | field  |
+      | pdfa                      | PDF/A-1a             | field  |
+      | Gotenberg-Output-Filename | encrypted            | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/libreoffice/convert with encryption (multiple files)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/libreoffice/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.docx | file   |
+      | files                     | testdata/page_2.docx | file   |
+      | userPassword              | test123              | field  |
+      | Gotenberg-Output-Filename | encrypted            | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be the following file(s) in the response:
+      | encrypted.zip |
+    Then the response PDF(s) should be encrypted
+    Then the "encrypted.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/libreoffice/convert with encryption and flattening
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/libreoffice/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.docx | file   |
+      | userPassword              | test123              | field  |
+      | flatten                   | true                 | field  |
+      | Gotenberg-Output-Filename | encrypted            | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 1 page(s)
+
+  Scenario: POST /forms/libreoffice/convert without encryption (empty password)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/libreoffice/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.docx | file   |
+      | userPassword              |                      | field  |
+      | Gotenberg-Output-Filename | unencrypted          | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | unencrypted.pdf |
+    Then the "unencrypted.pdf" PDF should NOT be encrypted
+    Then the "unencrypted.pdf" PDF should have 1 page(s)
diff --git a/test/integration/features/pdfengines_convert.feature b/test/integration/features/pdfengines_convert.feature
index 867dfcf..b0a77df 100644
--- a/test/integration/features/pdfengines_convert.feature
+++ b/test/integration/features/pdfengines_convert.feature
@@ -183,3 +183,78 @@ Feature: /forms/pdfengines/convert
       | pdfa  | PDF/A-1b            | field |
     Then the response status code should be 200
     Then the response header "Content-Type" should be "application/pdf"
+
+  Scenario: POST /forms/pdfengines/convert with encryption (user password only)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | pdfa                      | PDF/A-1b            | field  |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | encrypted           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should be valid "PDF/A-1b" with a tolerance of 1 failed rule(s)
+
+  Scenario: POST /forms/pdfengines/convert with encryption (user and owner passwords)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | pdfa                      | PDF/A-1b            | field  |
+      | userPassword              | user123             | field  |
+      | ownerPassword             | owner456            | field  |
+      | Gotenberg-Output-Filename | encrypted           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should be valid "PDF/A-1b" with a tolerance of 1 failed rule(s)
+
+  Scenario: POST /forms/pdfengines/convert with encryption (multiple files)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | files                     | testdata/page_2.pdf | file   |
+      | pdfa                      | PDF/A-1b            | field  |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | encrypted           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be the following file(s) in the response:
+      | encrypted.zip |
+    Then the response PDF(s) should be encrypted
+    Then the "encrypted.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/pdfengines/convert with encryption and PDF/UA
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | pdfua                     | true                | field  |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | encrypted           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+
+  Scenario: POST /forms/pdfengines/convert without encryption (empty password)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/convert" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | pdfa                      | PDF/A-1b            | field  |
+      | userPassword              |                     | field  |
+      | Gotenberg-Output-Filename | unencrypted         | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | unencrypted.pdf |
+    Then the "unencrypted.pdf" PDF should NOT be encrypted
+    Then the "unencrypted.pdf" PDF should be valid "PDF/A-1b" with a tolerance of 1 failed rule(s)
diff --git a/test/integration/features/pdfengines_encrypt.feature b/test/integration/features/pdfengines_encrypt.feature
new file mode 100644
index 0000000..2890169
--- /dev/null
+++ b/test/integration/features/pdfengines_encrypt.feature
@@ -0,0 +1,129 @@
+Feature: /forms/pdfengines/encrypt
+
+  Scenario: POST /forms/pdfengines/encrypt (default - QPDF)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | protected           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | protected.pdf |
+    Then the "protected.pdf" PDF should be encrypted
+
+  Scenario: POST /forms/pdfengines/encrypt with user and owner passwords (QPDF)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | userPassword              | user123             | field  |
+      | ownerPassword             | owner456            | field  |
+      | Gotenberg-Output-Filename | protected           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | protected.pdf |
+    Then the "protected.pdf" PDF should be encrypted
+
+  Scenario: POST /forms/pdfengines/encrypt (PDFtk)
+    Given I have a Gotenberg container with the following environment variable(s):
+      | PDFENGINES_PASSWORD_ENGINES | pdftk |
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | protected           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | protected.pdf |
+    Then the "protected.pdf" PDF should be encrypted
+
+  Scenario: POST /forms/pdfengines/encrypt (pdfcpu)
+    Given I have a Gotenberg container with the following environment variable(s):
+      | PDFENGINES_PASSWORD_ENGINES | pdfcpu |
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | protected           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | protected.pdf |
+    Then the "protected.pdf" PDF should be encrypted
+
+  Scenario: POST /forms/pdfengines/encrypt with multiple files
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | files                     | testdata/page_2.pdf | file   |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | protected           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be the following file(s) in the response:
+      | protected.zip |
+    Then the "protected.zip" archive should contain 2 file(s)
+    Then the "protected.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/pdfengines/encrypt without required userPassword field
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | Gotenberg-Output-Filename | protected           | header |
+    Then the response status code should be 400
+    Then the response body should contain "userPassword"
+
+  Scenario: POST /forms/pdfengines/encrypt with password engines that don't support password protection
+    Given I have a Gotenberg container with the following environment variable(s):
+      | PDFENGINES_PASSWORD_ENGINES | exiftool |
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | protected           | header |
+    Then the response status code should be 500
+    Then the response body should contain "password protection not supported"
+
+  Scenario: POST /forms/pdfengines/encrypt (Download From)
+    Given I have a default Gotenberg container
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | downloadFrom | [{"url":"http://host.docker.internal:%d/static/testdata/page_1.pdf","extraHttpHeaders":{"X-Foo":"bar"}}] | field |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | protected           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | protected.pdf |
+    Then the "protected.pdf" PDF should be encrypted
+
+  Scenario: POST /forms/pdfengines/encrypt (Webhook)
+    Given I have a default Gotenberg container
+    Given I have a webhook server
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | files                       | testdata/page_1.pdf                          | file   |
+      | Gotenberg-Output-Filename   | foo                                          | header |
+      | Gotenberg-Webhook-Url       | http://host.docker.internal:%d/webhook       | header |
+      | Gotenberg-Webhook-Error-Url | http://host.docker.internal:%d/webhook/error | header |
+    Then the response status code should be 204
+    When I wait for the asynchronous request to the webhook
+    Then the webhook request header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the webhook request
+    Then there should be the following file(s) in the webhook request:
+      | foo.pdf |
+    Then the "foo.pdf" PDF should have 1 page(s)
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Page 1
+      """
+
+  Scenario: POST /forms/pdfengines/encrypt (Routes Disabled)
+    Given I have a Gotenberg container with the following environment variable(s):
+      | PDFENGINES_DISABLE_ROUTES | true |
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/encrypt" endpoint with the following form data and header(s):
+      | files     | testdata/pages_3.pdf | file  |
+    Then the response status code should be 404
diff --git a/test/integration/features/pdfengines_merge.feature b/test/integration/features/pdfengines_merge.feature
index 248a81a..b6fdae9 100644
--- a/test/integration/features/pdfengines_merge.feature
+++ b/test/integration/features/pdfengines_merge.feature
@@ -322,3 +322,81 @@ Feature: /forms/pdfengines/merge
       | files | testdata/page_2.pdf | file |
     Then the response status code should be 200
     Then the response header "Content-Type" should be "application/pdf"
+
+  Scenario: POST /forms/pdfengines/merge with encryption (user password only)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/merge" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | files                     | testdata/page_2.pdf | file   |
+      | userPassword              | test123             | field  |
+      | Gotenberg-Output-Filename | encrypted           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 2 page(s)
+
+  Scenario: POST /forms/pdfengines/merge with encryption (user and owner passwords)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/merge" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | files                     | testdata/page_2.pdf | file   |
+      | userPassword              | user123             | field  |
+      | ownerPassword             | owner456            | field  |
+      | Gotenberg-Output-Filename | encrypted           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 2 page(s)
+
+  Scenario: POST /forms/pdfengines/merge with encryption and PDF/A conversion
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/merge" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | files                     | testdata/page_2.pdf | file   |
+      | userPassword              | test123             | field  |
+      | pdfa                      | PDF/A-1a            | field  |
+      | Gotenberg-Output-Filename | encrypted           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 2 page(s)
+
+  Scenario: POST /forms/pdfengines/merge with encryption and flattening
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/merge" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | files                     | testdata/page_2.pdf | file   |
+      | userPassword              | test123             | field  |
+      | flatten                   | true                | field  |
+      | Gotenberg-Output-Filename | encrypted           | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+    Then the "encrypted.pdf" PDF should have 2 page(s)
+
+  Scenario: POST /forms/pdfengines/merge without encryption (empty password)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/merge" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf | file   |
+      | files                     | testdata/page_2.pdf | file   |
+      | userPassword              |                     | field  |
+      | Gotenberg-Output-Filename | unencrypted         | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | unencrypted.pdf |
+    Then the "unencrypted.pdf" PDF should NOT be encrypted
+    Then the "unencrypted.pdf" PDF should have 2 page(s)
diff --git a/test/integration/features/pdfengines_metadata.feature b/test/integration/features/pdfengines_metadata.feature
index 9c75588..3cd0b29 100644
--- a/test/integration/features/pdfengines_metadata.feature
+++ b/test/integration/features/pdfengines_metadata.feature
@@ -284,3 +284,61 @@ Feature: /forms/pdfengines/{write|read}
       | files | teststore/foo.pdf | file |
     Then the response status code should be 200
     Then the response header "Content-Type" should be "application/json"
+
+  Scenario: POST /forms/pdfengines/metadata/write with encryption (user password only)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/metadata/write" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf                                                           | file   |
+      | metadata                  | {"Title":"Encrypted Sample","Author":"Test Author","Subject":"Test Subject"} | field  |
+      | userPassword              | test123                                                                       | field  |
+      | Gotenberg-Output-Filename | encrypted                                                                     | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+
+  Scenario: POST /forms/pdfengines/metadata/write with encryption (user and owner passwords)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/metadata/write" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf                                                           | file   |
+      | metadata                  | {"Title":"Encrypted Sample","Author":"Test Author","Subject":"Test Subject"} | field  |
+      | userPassword              | user123                                                                       | field  |
+      | ownerPassword             | owner456                                                                      | field  |
+      | Gotenberg-Output-Filename | encrypted                                                                     | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.pdf |
+    Then the "encrypted.pdf" PDF should be encrypted
+
+  Scenario: POST /forms/pdfengines/metadata/write with encryption (multiple files)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/metadata/write" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf                                                           | file   |
+      | files                     | testdata/page_2.pdf                                                           | file   |
+      | metadata                  | {"Title":"Encrypted Sample","Author":"Test Author","Subject":"Test Subject"} | field  |
+      | userPassword              | test123                                                                       | field  |
+      | Gotenberg-Output-Filename | encrypted                                                                     | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be the following file(s) in the response:
+      | encrypted.zip |
+    Then the response PDF(s) should be encrypted
+    Then the "encrypted.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/pdfengines/metadata/write without encryption (empty password)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/metadata/write" endpoint with the following form data and header(s):
+      | files                     | testdata/page_1.pdf                                                           | file   |
+      | metadata                  | {"Title":"Unencrypted Sample","Author":"Test Author","Subject":"Test Subject"} | field  |
+      | userPassword              |                                                                               | field  |
+      | Gotenberg-Output-Filename | unencrypted                                                                   | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | unencrypted.pdf |
+    Then the "unencrypted.pdf" PDF should NOT be encrypted
diff --git a/test/integration/features/pdfengines_split.feature b/test/integration/features/pdfengines_split.feature
index d9813bf..d336239 100644
--- a/test/integration/features/pdfengines_split.feature
+++ b/test/integration/features/pdfengines_split.feature
@@ -549,3 +549,69 @@ Feature: /forms/pdfengines/split
       | splitSpan | 2                    | field |
     Then the response status code should be 200
     Then the response header "Content-Type" should be "application/zip"
+
+  Scenario: POST /forms/pdfengines/split with encryption (intervals)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/split" endpoint with the following form data and header(s):
+      | files                     | testdata/pages_3.pdf | file   |
+      | splitMode                 | intervals            | field  |
+      | splitSpan                 | 2                    | field  |
+      | userPassword              | test123              | field  |
+      | Gotenberg-Output-Filename | encrypted            | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be 2 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.zip |
+    Then the response PDF(s) should be encrypted
+    Then the "encrypted.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/pdfengines/split with encryption (pages)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/split" endpoint with the following form data and header(s):
+      | files                     | testdata/pages_3.pdf | file   |
+      | splitMode                 | pages                | field  |
+      | splitSpan                 | 2-                   | field  |
+      | userPassword              | user123              | field  |
+      | ownerPassword             | owner456             | field  |
+      | Gotenberg-Output-Filename | encrypted            | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be 2 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.zip |
+    Then the response PDF(s) should be encrypted
+    Then the "encrypted.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/pdfengines/split with encryption and PDF/A conversion
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/split" endpoint with the following form data and header(s):
+      | files                     | testdata/pages_3.pdf | file   |
+      | splitMode                 | intervals            | field  |
+      | splitSpan                 | 2                    | field  |
+      | userPassword              | test123              | field  |
+      | pdfa                      | PDF/A-1a             | field  |
+      | Gotenberg-Output-Filename | encrypted            | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be 2 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | encrypted.zip |
+    Then the response PDF(s) should be encrypted
+    Then the "encrypted.zip" archive should contain encrypted PDF file(s)
+
+  Scenario: POST /forms/pdfengines/split without encryption (empty password)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/pdfengines/split" endpoint with the following form data and header(s):
+      | files                     | testdata/pages_3.pdf | file   |
+      | splitMode                 | intervals            | field  |
+      | splitSpan                 | 2                    | field  |
+      | userPassword              |                      | field  |
+      | Gotenberg-Output-Filename | unencrypted          | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/zip"
+    Then there should be 2 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | unencrypted.zip |
+    Then the "unencrypted.zip" archive should contain 2 file(s)
+    Then the "unencrypted.zip" archive should NOT contain encrypted PDF file(s)
diff --git a/test/integration/scenario/scenario.go b/test/integration/scenario/scenario.go
index a8f31a9..8a66667 100644
--- a/test/integration/scenario/scenario.go
+++ b/test/integration/scenario/scenario.go
@@ -839,6 +839,98 @@ func (s *scenario) thePdfsShouldBeFlatten(ctx context.Context, kind, should stri
 	return nil
 }
 
+// thePdfShouldBeEncrypted checks if a PDF file is encrypted or not encrypted based on condition.
+func (s *scenario) thePdfShouldBeEncrypted(ctx context.Context, filename, should string) error {
+	filePath := fmt.Sprintf("%s/%s", s.workdir, filename)
+
+	cmd := []string{
+		"qpdf",
+		"--check",
+		filepath.Base(filePath),
+	}
+
+	output, err := execCommandInIntegrationToolsContainer(ctx, cmd, filePath)
+
+	invert := should == "should NOT"
+	isEncrypted := err != nil && (strings.Contains(output, "password") || strings.Contains(output, "encrypted"))
+
+	if invert && isEncrypted {
+		return fmt.Errorf("expected PDF %s to not be encrypted, but it is encrypted", filename)
+	}
+
+	if !invert && !isEncrypted {
+		return fmt.Errorf("expected PDF %s to be encrypted, but it is not", filename)
+	}
+
+	return nil
+}
+
+// theArchiveShouldContainEncryptedPdfFiles checks if a zip archive contains encrypted PDF files based on condition.
+func (s *scenario) theArchiveShouldContainEncryptedPdfFiles(ctx context.Context, archiveFilename, should string) error {
+	archivePath := fmt.Sprintf("%s/%s", s.workdir, archiveFilename)
+
+	// First, extract the archive inside the container
+	extractCmd := []string{
+		"sh",
+		"-c",
+		fmt.Sprintf("mkdir -p /tmp/extract && unzip -o %s -d /tmp/extract", filepath.Base(archivePath)),
+	}
+
+	_, err := execCommandInIntegrationToolsContainer(ctx, extractCmd, archivePath)
+	if err != nil {
+		return fmt.Errorf("extract archive in container: %w", err)
+	}
+
+	// List PDF files in the extracted directory
+	listCmd := []string{
+		"sh",
+		"-c",
+		"find /tmp/extract -name '*.pdf' -type f",
+	}
+
+	output, err := execCommandInIntegrationToolsContainer(ctx, listCmd, archivePath)
+	if err != nil {
+		return fmt.Errorf("list PDFs in container: %w", err)
+	}
+
+	// No PDFs found
+	if output == "" {
+		return fmt.Errorf("no PDF files found in archive %s", archiveFilename)
+	}
+
+	// Check each PDF for password protection
+	pdfPaths := strings.Split(strings.TrimSpace(output), "\n")
+	foundProtectedPdf := false
+
+	for _, pdfPath := range pdfPaths {
+		checkCmd := []string{
+			"qpdf",
+			"--check",
+			pdfPath,
+		}
+
+		checkOutput, err := execCommandInIntegrationToolsContainer(ctx, checkCmd, archivePath)
+
+		// If we get a password error, we found a protected PDF
+		if err != nil && (strings.Contains(checkOutput, "password") || strings.Contains(checkOutput, "encrypted")) {
+			foundProtectedPdf = true
+			break
+		}
+	}
+
+	invert := should == "should NOT"
+
+	if invert && foundProtectedPdf {
+		return fmt.Errorf("found encrypted PDF files in archive %s, but expected none", archiveFilename)
+	}
+
+	if !invert && !foundProtectedPdf {
+		return fmt.Errorf("no encrypted PDF files found in archive %s", archiveFilename)
+	}
+
+	return nil
+}
+
 func InitializeScenario(ctx *godog.ScenarioContext) {
 	s := &scenario{}
 	ctx.Before(func(ctx context.Context, sc *godog.Scenario) (context.Context, error) {
@@ -874,6 +966,8 @@ func InitializeScenario(ctx *godog.ScenarioContext) {
 	ctx.Then(`^the "([^"]*)" PDF should have (\d+) page\(s\)$`, s.thePdfShouldHavePages)
 	ctx.Then(`^the "([^"]*)" PDF (should|should NOT) be set to landscape orientation$`, s.thePdfShouldBeSetToLandscapeOrientation)
 	ctx.Then(`^the "([^"]*)" PDF (should|should NOT) have the following content at page (\d+):$`, s.thePdfShouldHaveTheFollowingContentAtPage)
+	ctx.Then(`^the "([^"]*)" PDF (should|should NOT) be encrypted$`, s.thePdfShouldBeEncrypted)
+	ctx.Then(`^the "([^"]*)" archive (should|should NOT) contain encrypted PDF file\(s\)$`, s.theArchiveShouldContainEncryptedPdfFiles)
 	ctx.After(func(ctx context.Context, sc *godog.Scenario, err error) (context.Context, error) {
 		if s.gotenbergContainer != nil {
 			errTerminate := s.gotenbergContainer.Terminate(ctx, testcontainers.StopTimeout(0))