Save signatures to server (#5080)

# Description of Changes

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Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)
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---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>

app/common/src/main/java/stirling/software/common/service/PersonalSignatureServiceInterface.java

@@ -0,0 +1,21 @@
+package stirling.software.common.service;
+
+import java.io.IOException;
+
+/**
+ * Interface for personal signature access (proprietary feature). Implemented only in proprietary
+ * module to provide authenticated users access to their personal signatures.
+ */
+public interface PersonalSignatureServiceInterface {
+
+    /**
+     * Get a personal signature from the user's folder. Only checks personal folder, not shared
+     * folder.
+     *
+     * @param username Username of the signature owner
+     * @param fileName Signature filename
+     * @return Personal signature image bytes
+     * @throws IOException If file not found or read error
+     */
+    byte[] getPersonalSignatureBytes(String username, String fileName) throws IOException;
+}

app/core/src/main/java/stirling/software/SPDF/controller/api/UIDataController.java

@@ -26,7 +26,7 @@ import lombok.extern.slf4j.Slf4j;
 
 import stirling.software.SPDF.model.Dependency;
 import stirling.software.SPDF.model.SignatureFile;
-import stirling.software.SPDF.service.SignatureService;
+import stirling.software.SPDF.service.SharedSignatureService;
 import stirling.software.common.annotations.api.UiDataApi;
 import stirling.software.common.configuration.InstallationPathConfig;
 import stirling.software.common.configuration.RuntimePathConfig;
@@ -40,14 +40,14 @@ import stirling.software.common.util.GeneralUtils;
 public class UIDataController {
 
     private final ApplicationProperties applicationProperties;
-    private final SignatureService signatureService;
+    private final SharedSignatureService signatureService;
     private final UserServiceInterface userService;
     private final ResourceLoader resourceLoader;
     private final RuntimePathConfig runtimePathConfig;
 
     public UIDataController(
             ApplicationProperties applicationProperties,
-            SignatureService signatureService,
+            SharedSignatureService signatureService,
             @Autowired(required = false) UserServiceInterface userService,
             ResourceLoader resourceLoader,
             RuntimePathConfig runtimePathConfig) {

app/core/src/main/java/stirling/software/SPDF/controller/web/GeneralWebController.java

@@ -25,7 +25,7 @@ import lombok.Setter;
 import lombok.extern.slf4j.Slf4j;
 
 import stirling.software.SPDF.model.SignatureFile;
-import stirling.software.SPDF.service.SignatureService;
+import stirling.software.SPDF.service.SharedSignatureService;
 import stirling.software.common.configuration.InstallationPathConfig;
 import stirling.software.common.configuration.RuntimePathConfig;
 import stirling.software.common.service.UserServiceInterface;
@@ -37,13 +37,13 @@ import stirling.software.common.util.GeneralUtils;
 @Slf4j
 public class GeneralWebController {
 
-    private final SignatureService signatureService;
+    private final SharedSignatureService signatureService;
     private final UserServiceInterface userService;
     private final ResourceLoader resourceLoader;
     private final RuntimePathConfig runtimePathConfig;
 
     public GeneralWebController(
-            SignatureService signatureService,
+            SharedSignatureService signatureService,
             @Autowired(required = false) UserServiceInterface userService,
             ResourceLoader resourceLoader,
             RuntimePathConfig runtimePathConfig) {

app/core/src/main/java/stirling/software/SPDF/controller/web/SignatureController.java

@@ -1,48 +0,0 @@
-package stirling.software.SPDF.controller.web;
-
-import java.io.IOException;
-
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.http.HttpStatus;
-import org.springframework.http.MediaType;
-import org.springframework.http.ResponseEntity;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.PathVariable;
-import org.springframework.web.bind.annotation.RequestMapping;
-
-import stirling.software.SPDF.service.SignatureService;
-import stirling.software.common.service.UserServiceInterface;
-
-// @Controller // Disabled - Backend-only mode, no Thymeleaf UI
-@RequestMapping("/api/v1/general")
-public class SignatureController {
-
-    private final SignatureService signatureService;
-
-    private final UserServiceInterface userService;
-
-    public SignatureController(
-            SignatureService signatureService,
-            @Autowired(required = false) UserServiceInterface userService) {
-        this.signatureService = signatureService;
-        this.userService = userService;
-    }
-
-    @GetMapping("/sign/{fileName}")
-    public ResponseEntity<byte[]> getSignature(@PathVariable(name = "fileName") String fileName)
-            throws IOException {
-        String username = "NON_SECURITY_USER";
-        if (userService != null) {
-            username = userService.getCurrentUsername();
-        }
-        // Verify access permission
-        if (!signatureService.hasAccessToFile(username, fileName)) {
-            return ResponseEntity.status(HttpStatus.FORBIDDEN).build();
-        }
-        byte[] imageBytes = signatureService.getSignatureBytes(username, fileName);
-        return ResponseEntity.ok()
-                .contentType( // Adjust based on file type
-                        MediaType.IMAGE_JPEG)
-                .body(imageBytes);
-    }
-}

app/core/src/main/java/stirling/software/SPDF/controller/web/SignatureImageController.java

@@ -0,0 +1,84 @@
+package stirling.software.SPDF.controller.web;
+
+import java.io.IOException;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import lombok.extern.slf4j.Slf4j;
+
+import stirling.software.SPDF.service.SharedSignatureService;
+import stirling.software.common.service.PersonalSignatureServiceInterface;
+import stirling.software.common.service.UserServiceInterface;
+
+/**
+ * Unified signature image controller that works for both authenticated and unauthenticated users.
+ * Uses composition pattern: - Core SharedSignatureService (always available): reads shared signatures -
+ * PersonalSignatureService (proprietary, optional): reads personal signatures For authenticated
+ * signature management (save/delete), see proprietary SignatureController.
+ */
+@Slf4j
+@RestController
+@RequestMapping("/api/v1/general")
+public class SignatureImageController {
+
+    private final SharedSignatureService sharedSignatureService;
+    private final PersonalSignatureServiceInterface personalSignatureService;
+    private final UserServiceInterface userService;
+
+    public SignatureImageController(
+            SharedSignatureService sharedSignatureService,
+            @Autowired(required = false) PersonalSignatureServiceInterface personalSignatureService,
+            @Autowired(required = false) UserServiceInterface userService) {
+        this.sharedSignatureService = sharedSignatureService;
+        this.personalSignatureService = personalSignatureService;
+        this.userService = userService;
+    }
+
+    /**
+     * Get a signature image (works for both authenticated and unauthenticated users). -
+     * Authenticated with proprietary: tries personal first, then shared - Unauthenticated or
+     * community: tries shared only
+     */
+    @GetMapping("/signatures/{fileName}")
+    public ResponseEntity<byte[]> getSignature(@PathVariable(name = "fileName") String fileName) {
+        try {
+            byte[] imageBytes = null;
+
+            // If proprietary service available and user authenticated, try personal folder first
+            if (personalSignatureService != null && userService != null) {
+                try {
+                    String username = userService.getCurrentUsername();
+                    imageBytes =
+                            personalSignatureService.getPersonalSignatureBytes(username, fileName);
+                } catch (Exception e) {
+                    // Not found in personal folder or not authenticated, will try shared
+                    log.debug("Personal signature not found, trying shared: {}", e.getMessage());
+                }
+            }
+
+            // If not found in personal (or no personal service), try shared
+            if (imageBytes == null) {
+                imageBytes = sharedSignatureService.getSharedSignatureBytes(fileName);
+            }
+
+            // Determine content type from file extension
+            MediaType contentType = MediaType.IMAGE_PNG; // Default
+            String lowerFileName = fileName.toLowerCase();
+            if (lowerFileName.endsWith(".jpg") || lowerFileName.endsWith(".jpeg")) {
+                contentType = MediaType.IMAGE_JPEG;
+            }
+
+            return ResponseEntity.ok().contentType(contentType).body(imageBytes);
+        } catch (IOException e) {
+            log.debug("Signature not found: {}", fileName);
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
+        }
+    }
+}

app/core/src/main/java/stirling/software/SPDF/model/api/signature/SavedSignatureRequest.java

@@ -0,0 +1,18 @@
+package stirling.software.SPDF.model.api.signature;
+
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+public class SavedSignatureRequest {
+    private String id;
+    private String label;
+    private String type; // "canvas", "image", "text"
+    private String scope; // "personal", "shared"
+    private String dataUrl; // For canvas and image types
+    private String signerName; // For text type
+    private String fontFamily; // For text type
+    private Integer fontSize; // For text type
+    private String textColor; // For text type
+}

app/core/src/main/java/stirling/software/SPDF/model/api/signature/SavedSignatureResponse.java

@@ -0,0 +1,22 @@
+package stirling.software.SPDF.model.api.signature;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class SavedSignatureResponse {
+    private String id;
+    private String label;
+    private String type; // "canvas", "image", "text"
+    private String scope; // "personal", "shared"
+    private String dataUrl; // For canvas and image types (or URL to fetch image)
+    private String signerName; // For text type
+    private String fontFamily; // For text type
+    private Integer fontSize; // For text type
+    private String textColor; // For text type
+    private Long createdAt;
+    private Long updatedAt;
+}

app/core/src/main/java/stirling/software/SPDF/service/SharedSignatureService.java

@@ -0,0 +1,308 @@
+package stirling.software.SPDF.service;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+import java.util.ArrayList;
+import java.util.Base64;
+import java.util.List;
+import java.util.stream.Stream;
+
+import org.springframework.stereotype.Service;
+import org.springframework.util.StringUtils;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import lombok.extern.slf4j.Slf4j;
+
+import stirling.software.SPDF.model.SignatureFile;
+import stirling.software.SPDF.model.api.signature.SavedSignatureRequest;
+import stirling.software.SPDF.model.api.signature.SavedSignatureResponse;
+import stirling.software.common.configuration.InstallationPathConfig;
+
+@Service
+@Slf4j
+public class SharedSignatureService {
+
+    private final String SIGNATURE_BASE_PATH;
+    private final String ALL_USERS_FOLDER = "ALL_USERS";
+    private final ObjectMapper objectMapper;
+
+    public SharedSignatureService() {
+        SIGNATURE_BASE_PATH = InstallationPathConfig.getSignaturesPath();
+        this.objectMapper = new ObjectMapper();
+    }
+
+    public boolean hasAccessToFile(String username, String fileName) throws IOException {
+        validateFileName(fileName);
+        // Check if file exists in user's personal folder or ALL_USERS folder
+        Path userPath = Paths.get(SIGNATURE_BASE_PATH, username, fileName);
+        Path allUsersPath = Paths.get(SIGNATURE_BASE_PATH, ALL_USERS_FOLDER, fileName);
+
+        return Files.exists(userPath) || Files.exists(allUsersPath);
+    }
+
+    public List<SignatureFile> getAvailableSignatures(String username) {
+        List<SignatureFile> signatures = new ArrayList<>();
+
+        // Get signatures from user's personal folder
+        if (StringUtils.hasText(username)) {
+            Path userFolder = Paths.get(SIGNATURE_BASE_PATH, username);
+            if (Files.exists(userFolder)) {
+                try {
+                    signatures.addAll(getSignaturesFromFolder(userFolder, "Personal"));
+                } catch (IOException e) {
+                    log.error("Error reading user signatures folder", e);
+                }
+            }
+        }
+
+        // Get signatures from ALL_USERS folder
+        Path allUsersFolder = Paths.get(SIGNATURE_BASE_PATH, ALL_USERS_FOLDER);
+        if (Files.exists(allUsersFolder)) {
+            try {
+                signatures.addAll(getSignaturesFromFolder(allUsersFolder, "Shared"));
+            } catch (IOException e) {
+                log.error("Error reading shared signatures folder", e);
+            }
+        }
+
+        return signatures;
+    }
+
+    private List<SignatureFile> getSignaturesFromFolder(Path folder, String category)
+            throws IOException {
+        try (Stream<Path> stream = Files.list(folder)) {
+            return stream.filter(this::isImageFile)
+                    .map(path -> new SignatureFile(path.getFileName().toString(), category))
+                    .toList();
+        }
+    }
+
+    /**
+     * Get a signature from the shared (ALL_USERS) folder. This is always available for both
+     * authenticated and unauthenticated users.
+     */
+    public byte[] getSharedSignatureBytes(String fileName) throws IOException {
+        validateFileName(fileName);
+        Path allUsersPath = Paths.get(SIGNATURE_BASE_PATH, ALL_USERS_FOLDER, fileName);
+        if (!Files.exists(allUsersPath)) {
+            throw new FileNotFoundException("Shared signature file not found");
+        }
+        return Files.readAllBytes(allUsersPath);
+    }
+
+    private boolean isImageFile(Path path) {
+        String fileName = path.getFileName().toString().toLowerCase();
+        return fileName.endsWith(".jpg") || fileName.endsWith(".jpeg") || fileName.endsWith(".png");
+    }
+
+    private void validateFileName(String fileName) {
+        if (fileName.contains("..") || fileName.contains("/") || fileName.contains("\\")) {
+            throw new IllegalArgumentException("Invalid filename");
+        }
+        // Only allow alphanumeric, hyphen, underscore, and dot (for extensions)
+        if (!fileName.matches("^[a-zA-Z0-9_.-]+$")) {
+            throw new IllegalArgumentException("Filename contains invalid characters");
+        }
+    }
+
+    private String validateAndNormalizeExtension(String extension) {
+        String normalized = extension.toLowerCase().trim();
+        // Whitelist only safe image extensions
+        if (normalized.equals("png") || normalized.equals("jpg") || normalized.equals("jpeg")) {
+            return normalized;
+        }
+        throw new IllegalArgumentException("Unsupported image extension: " + extension);
+    }
+
+    private void verifyPathWithinDirectory(Path resolvedPath, Path targetDirectory)
+            throws IOException {
+        Path canonicalTarget = targetDirectory.toAbsolutePath().normalize();
+        Path canonicalResolved = resolvedPath.toAbsolutePath().normalize();
+        if (!canonicalResolved.startsWith(canonicalTarget)) {
+            throw new IOException("Resolved path is outside the target directory");
+        }
+    }
+
+    /** Save a signature as image file */
+    public SavedSignatureResponse saveSignature(String username, SavedSignatureRequest request)
+            throws IOException {
+        validateFileName(request.getId());
+
+        // Determine folder based on scope
+        String scope = request.getScope();
+        if (scope == null || scope.isEmpty()) {
+            scope = "personal"; // Default to personal
+        }
+
+        String folderName = "shared".equals(scope) ? ALL_USERS_FOLDER : username;
+        Path targetFolder = Paths.get(SIGNATURE_BASE_PATH, folderName);
+        Files.createDirectories(targetFolder);
+
+        long timestamp = System.currentTimeMillis();
+
+        SavedSignatureResponse response = new SavedSignatureResponse();
+        response.setId(request.getId());
+        response.setLabel(request.getLabel());
+        response.setType(request.getType());
+        response.setScope(scope);
+        response.setCreatedAt(timestamp);
+        response.setUpdatedAt(timestamp);
+
+        // Extract and save image data
+        String dataUrl = request.getDataUrl();
+        if (dataUrl != null && dataUrl.startsWith("data:image/")) {
+            // Extract base64 data
+            String base64Data = dataUrl.substring(dataUrl.indexOf(",") + 1);
+            byte[] imageBytes = Base64.getDecoder().decode(base64Data);
+
+            // Determine and validate file extension from data URL
+            String mimeType = dataUrl.substring(dataUrl.indexOf(":") + 1, dataUrl.indexOf(";"));
+            String rawExtension = mimeType.substring(mimeType.indexOf("/") + 1);
+            String extension = validateAndNormalizeExtension(rawExtension);
+
+            // Save image file only
+            String imageFileName = request.getId() + "." + extension;
+            Path imagePath = targetFolder.resolve(imageFileName);
+
+            // Verify path is within target directory
+            verifyPathWithinDirectory(imagePath, targetFolder);
+
+            Files.write(
+                    imagePath,
+                    imageBytes,
+                    StandardOpenOption.CREATE,
+                    StandardOpenOption.TRUNCATE_EXISTING);
+
+            // Store reference to image file
+            response.setDataUrl("/api/v1/general/sign/" + imageFileName);
+        }
+
+        log.info("Saved signature {} for user {}", request.getId(), username);
+        return response;
+    }
+
+    /** Get all saved signatures for a user */
+    public List<SavedSignatureResponse> getSavedSignatures(String username) throws IOException {
+        List<SavedSignatureResponse> signatures = new ArrayList<>();
+
+        // Load personal signatures
+        Path personalFolder = Paths.get(SIGNATURE_BASE_PATH, username);
+        if (Files.exists(personalFolder)) {
+            try (Stream<Path> stream = Files.list(personalFolder)) {
+                stream.filter(this::isImageFile)
+                        .forEach(
+                                path -> {
+                                    try {
+                                        String fileName = path.getFileName().toString();
+                                        String id =
+                                                fileName.substring(0, fileName.lastIndexOf('.'));
+
+                                        SavedSignatureResponse sig = new SavedSignatureResponse();
+                                        sig.setId(id);
+                                        sig.setLabel(id); // Use ID as label
+                                        sig.setType("image"); // Default type
+                                        sig.setScope("personal");
+                                        sig.setDataUrl("/api/v1/general/sign/" + fileName);
+                                        sig.setCreatedAt(
+                                                Files.getLastModifiedTime(path).toMillis());
+                                        sig.setUpdatedAt(
+                                                Files.getLastModifiedTime(path).toMillis());
+
+                                        signatures.add(sig);
+                                    } catch (IOException e) {
+                                        log.error("Error reading signature file: " + path, e);
+                                    }
+                                });
+            }
+        }
+
+        // Load shared signatures
+        Path sharedFolder = Paths.get(SIGNATURE_BASE_PATH, ALL_USERS_FOLDER);
+        if (Files.exists(sharedFolder)) {
+            try (Stream<Path> stream = Files.list(sharedFolder)) {
+                stream.filter(this::isImageFile)
+                        .forEach(
+                                path -> {
+                                    try {
+                                        String fileName = path.getFileName().toString();
+                                        String id =
+                                                fileName.substring(0, fileName.lastIndexOf('.'));
+
+                                        SavedSignatureResponse sig = new SavedSignatureResponse();
+                                        sig.setId(id);
+                                        sig.setLabel(id); // Use ID as label
+                                        sig.setType("image"); // Default type
+                                        sig.setScope("shared");
+                                        sig.setDataUrl("/api/v1/general/sign/" + fileName);
+                                        sig.setCreatedAt(
+                                                Files.getLastModifiedTime(path).toMillis());
+                                        sig.setUpdatedAt(
+                                                Files.getLastModifiedTime(path).toMillis());
+
+                                        signatures.add(sig);
+                                    } catch (IOException e) {
+                                        log.error("Error reading signature file: " + path, e);
+                                    }
+                                });
+            }
+        }
+
+        return signatures;
+    }
+
+    /** Delete a saved signature */
+    public void deleteSignature(String username, String signatureId) throws IOException {
+        validateFileName(signatureId);
+
+        // Try to find and delete image file in personal folder
+        Path personalFolder = Paths.get(SIGNATURE_BASE_PATH, username);
+        boolean deleted = false;
+
+        if (Files.exists(personalFolder)) {
+            try (Stream<Path> stream = Files.list(personalFolder)) {
+                List<Path> matchingFiles =
+                        stream.filter(
+                                        path ->
+                                                path.getFileName()
+                                                        .toString()
+                                                        .startsWith(signatureId + "."))
+                                .toList();
+                for (Path file : matchingFiles) {
+                    Files.delete(file);
+                    deleted = true;
+                }
+            }
+        }
+
+        // Try shared folder if not found in personal
+        if (!deleted) {
+            Path sharedFolder = Paths.get(SIGNATURE_BASE_PATH, ALL_USERS_FOLDER);
+            if (Files.exists(sharedFolder)) {
+                try (Stream<Path> stream = Files.list(sharedFolder)) {
+                    List<Path> matchingFiles =
+                            stream.filter(
+                                            path ->
+                                                    path.getFileName()
+                                                            .toString()
+                                                            .startsWith(signatureId + "."))
+                                    .toList();
+                    for (Path file : matchingFiles) {
+                        Files.delete(file);
+                        deleted = true;
+                    }
+                }
+            }
+        }
+
+        if (!deleted) {
+            throw new FileNotFoundException("Signature not found");
+        }
+
+        log.info("Deleted signature {} for user {}", signatureId, username);
+    }
+}

app/core/src/main/java/stirling/software/SPDF/service/SignatureService.java

@@ -1,107 +0,0 @@
-package stirling.software.SPDF.service;
-
-import java.io.FileNotFoundException;
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.stream.Stream;
-
-import org.springframework.stereotype.Service;
-import org.springframework.util.StringUtils;
-
-import lombok.extern.slf4j.Slf4j;
-
-import stirling.software.SPDF.model.SignatureFile;
-import stirling.software.common.configuration.InstallationPathConfig;
-
-@Service
-@Slf4j
-public class SignatureService {
-
-    private final String SIGNATURE_BASE_PATH;
-    private final String ALL_USERS_FOLDER = "ALL_USERS";
-
-    public SignatureService() {
-        SIGNATURE_BASE_PATH = InstallationPathConfig.getSignaturesPath();
-    }
-
-    public boolean hasAccessToFile(String username, String fileName) throws IOException {
-        validateFileName(fileName);
-        // Check if file exists in user's personal folder or ALL_USERS folder
-        Path userPath = Paths.get(SIGNATURE_BASE_PATH, username, fileName);
-        Path allUsersPath = Paths.get(SIGNATURE_BASE_PATH, ALL_USERS_FOLDER, fileName);
-
-        return Files.exists(userPath) || Files.exists(allUsersPath);
-    }
-
-    public List<SignatureFile> getAvailableSignatures(String username) {
-        List<SignatureFile> signatures = new ArrayList<>();
-
-        // Get signatures from user's personal folder
-        if (StringUtils.hasText(username)) {
-            Path userFolder = Paths.get(SIGNATURE_BASE_PATH, username);
-            if (Files.exists(userFolder)) {
-                try {
-                    signatures.addAll(getSignaturesFromFolder(userFolder, "Personal"));
-                } catch (IOException e) {
-                    log.error("Error reading user signatures folder", e);
-                }
-            }
-        }
-
-        // Get signatures from ALL_USERS folder
-        Path allUsersFolder = Paths.get(SIGNATURE_BASE_PATH, ALL_USERS_FOLDER);
-        if (Files.exists(allUsersFolder)) {
-            try {
-                signatures.addAll(getSignaturesFromFolder(allUsersFolder, "Shared"));
-            } catch (IOException e) {
-                log.error("Error reading shared signatures folder", e);
-            }
-        }
-
-        return signatures;
-    }
-
-    private List<SignatureFile> getSignaturesFromFolder(Path folder, String category)
-            throws IOException {
-        try (Stream<Path> stream = Files.list(folder)) {
-            return stream.filter(this::isImageFile)
-                    .map(path -> new SignatureFile(path.getFileName().toString(), category))
-                    .toList();
-        }
-    }
-
-    public byte[] getSignatureBytes(String username, String fileName) throws IOException {
-        validateFileName(fileName);
-        // First try user's personal folder
-        Path userPath = Paths.get(SIGNATURE_BASE_PATH, username, fileName);
-        if (Files.exists(userPath)) {
-            return Files.readAllBytes(userPath);
-        }
-
-        // Then try ALL_USERS folder
-        Path allUsersPath = Paths.get(SIGNATURE_BASE_PATH, ALL_USERS_FOLDER, fileName);
-        if (Files.exists(allUsersPath)) {
-            return Files.readAllBytes(allUsersPath);
-        }
-
-        throw new FileNotFoundException("Signature file not found");
-    }
-
-    private boolean isImageFile(Path path) {
-        String fileName = path.getFileName().toString().toLowerCase();
-        return fileName.endsWith(".jpg")
-                || fileName.endsWith(".jpeg")
-                || fileName.endsWith(".png")
-                || fileName.endsWith(".gif");
-    }
-
-    private void validateFileName(String fileName) {
-        if (fileName.contains("..") || fileName.contains("/") || fileName.contains("\\")) {
-            throw new IllegalArgumentException("Invalid filename");
-        }
-    }
-}

app/core/src/test/java/stirling/software/SPDF/service/SignatureServiceTest.java

@@ -23,7 +23,7 @@ import stirling.software.common.configuration.InstallationPathConfig;
 class SignatureServiceTest {
 
     @TempDir Path tempDir;
-    private SignatureService signatureService;
+    private SharedSignatureService signatureService;
     private Path personalSignatureFolder;
     private Path sharedSignatureFolder;
     private final String ALL_USERS_FOLDER = "ALL_USERS";
@@ -53,7 +53,7 @@ class SignatureServiceTest {
                     .thenReturn(tempDir.toString());
 
             // Initialize the service with our temp directory
-            signatureService = new SignatureService();
+            signatureService = new SharedSignatureService();
         }
     }
 
@@ -165,7 +165,7 @@ class SignatureServiceTest {
     }
 
     @Test
-    void testGetSignatureBytes_PersonalFile() throws IOException {
+    void testGetSharedSignatureBytes_SharedFile() throws IOException {
         // Mock static method for each test
         try (MockedStatic<InstallationPathConfig> mockedConfig =
                 mockStatic(InstallationPathConfig.class)) {
@@ -173,28 +173,8 @@ class SignatureServiceTest {
                     .when(InstallationPathConfig::getSignaturesPath)
                     .thenReturn(tempDir.toString());
 
-            // Test
-            byte[] bytes = signatureService.getSignatureBytes(TEST_USER, "personal.png");
-
-            // Verify
-            assertEquals(
-                    "personal signature content",
-                    new String(bytes),
-                    "Should return the correct content for personal file");
-        }
-    }
-
-    @Test
-    void testGetSignatureBytes_SharedFile() throws IOException {
-        // Mock static method for each test
-        try (MockedStatic<InstallationPathConfig> mockedConfig =
-                mockStatic(InstallationPathConfig.class)) {
-            mockedConfig
-                    .when(InstallationPathConfig::getSignaturesPath)
-                    .thenReturn(tempDir.toString());
-
-            // Test
-            byte[] bytes = signatureService.getSignatureBytes(TEST_USER, "shared.jpg");
+            // Test - core service only reads shared signatures
+            byte[] bytes = signatureService.getSharedSignatureBytes("shared.jpg");
 
             // Verify
             assertEquals(
@@ -205,7 +185,7 @@ class SignatureServiceTest {
     }
 
     @Test
-    void testGetSignatureBytes_FileNotFound() {
+    void testGetSharedSignatureBytes_FileNotFound() {
         // Mock static method for each test
         try (MockedStatic<InstallationPathConfig> mockedConfig =
                 mockStatic(InstallationPathConfig.class)) {
@@ -216,13 +196,13 @@ class SignatureServiceTest {
             // Test and verify
             assertThrows(
                     FileNotFoundException.class,
-                    () -> signatureService.getSignatureBytes(TEST_USER, "nonexistent.png"),
+                    () -> signatureService.getSharedSignatureBytes("nonexistent.png"),
                     "Should throw exception for non-existent files");
         }
     }
 
     @Test
-    void testGetSignatureBytes_InvalidFileName() {
+    void testGetSharedSignatureBytes_InvalidFileName() {
         // Mock static method for each test
         try (MockedStatic<InstallationPathConfig> mockedConfig =
                 mockStatic(InstallationPathConfig.class)) {
@@ -233,11 +213,28 @@ class SignatureServiceTest {
             // Test and verify
             assertThrows(
                     IllegalArgumentException.class,
-                    () -> signatureService.getSignatureBytes(TEST_USER, "../invalid.png"),
+                    () -> signatureService.getSharedSignatureBytes("../invalid.png"),
                     "Should throw exception for file names with directory traversal");
         }
     }
 
+    @Test
+    void testGetSharedSignatureBytes_CannotAccessPersonalFiles() {
+        // Mock static method for each test
+        try (MockedStatic<InstallationPathConfig> mockedConfig =
+                mockStatic(InstallationPathConfig.class)) {
+            mockedConfig
+                    .when(InstallationPathConfig::getSignaturesPath)
+                    .thenReturn(tempDir.toString());
+
+            // Test and verify - core service should NOT be able to read personal files
+            assertThrows(
+                    FileNotFoundException.class,
+                    () -> signatureService.getSharedSignatureBytes("personal.png"),
+                    "Core service should not have access to personal signatures");
+        }
+    }
+
     @Test
     void testGetAvailableSignatures_EmptyUsername() throws IOException {
         // Mock static method for each test

app/proprietary/src/main/java/stirling/software/proprietary/controller/api/SignatureController.java

@@ -0,0 +1,102 @@
+package stirling.software.proprietary.controller.api;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+import stirling.software.common.annotations.api.UserApi;
+import stirling.software.proprietary.model.api.signature.SavedSignatureRequest;
+import stirling.software.proprietary.model.api.signature.SavedSignatureResponse;
+import stirling.software.proprietary.security.service.UserService;
+import stirling.software.proprietary.service.SignatureService;
+
+/**
+ * Controller for managing user signatures in proprietary/authenticated mode only. Requires user
+ * authentication and enforces per-user storage limits. All endpoints require authentication
+ * via @PreAuthorize("isAuthenticated()").
+ */
+@UserApi
+@Slf4j
+@RestController
+@RequestMapping("/api/v1/proprietary/signatures")
+@RequiredArgsConstructor
+@PreAuthorize("isAuthenticated()")
+public class SignatureController {
+
+    private final SignatureService signatureService;
+    private final UserService userService;
+
+    /**
+     * Save a new signature for the authenticated user. Enforces storage limits and authentication
+     * requirements.
+     */
+    @PostMapping
+    public ResponseEntity<SavedSignatureResponse> saveSignature(
+            @RequestBody SavedSignatureRequest request) {
+        try {
+            String username = userService.getCurrentUsername();
+
+            // Validate request
+            if (request.getDataUrl() == null || request.getDataUrl().isEmpty()) {
+                log.warn("User {} attempted to save signature without dataUrl", username);
+                return ResponseEntity.badRequest().build();
+            }
+
+            SavedSignatureResponse response = signatureService.saveSignature(username, request);
+            log.info("User {} saved signature {}", username, request.getId());
+            return ResponseEntity.ok(response);
+        } catch (IllegalArgumentException e) {
+            log.warn("Invalid signature save request: {}", e.getMessage());
+            return ResponseEntity.badRequest().build();
+        } catch (IOException e) {
+            log.error("Failed to save signature", e);
+            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
+        }
+    }
+
+    /**
+     * List all signatures accessible to the authenticated user. Includes both personal and shared
+     * signatures.
+     */
+    @GetMapping
+    public ResponseEntity<List<SavedSignatureResponse>> listSignatures() {
+        try {
+            String username = userService.getCurrentUsername();
+            List<SavedSignatureResponse> signatures = signatureService.getSavedSignatures(username);
+            return ResponseEntity.ok(signatures);
+        } catch (IOException e) {
+            log.error("Failed to list signatures for user", e);
+            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
+        }
+    }
+
+    /**
+     * Delete a signature owned by the authenticated user. Users can only delete their own personal
+     * signatures, not shared ones.
+     */
+    @DeleteMapping("/{signatureId}")
+    public ResponseEntity<Void> deleteSignature(@PathVariable String signatureId) {
+        try {
+            String username = userService.getCurrentUsername();
+            signatureService.deleteSignature(username, signatureId);
+            log.info("User {} deleted signature {}", username, signatureId);
+            return ResponseEntity.noContent().build();
+        } catch (IOException e) {
+            log.warn("Failed to delete signature {} for user: {}", signatureId, e.getMessage());
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
+        }
+    }
+}

app/proprietary/src/main/java/stirling/software/proprietary/model/api/signature/SavedSignatureRequest.java

@@ -0,0 +1,18 @@
+package stirling.software.proprietary.model.api.signature;
+
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+public class SavedSignatureRequest {
+    private String id;
+    private String label;
+    private String type; // "canvas", "image", "text"
+    private String scope; // "personal", "shared"
+    private String dataUrl; // For canvas and image types
+    private String signerName; // For text type
+    private String fontFamily; // For text type
+    private Integer fontSize; // For text type
+    private String textColor; // For text type
+}

app/proprietary/src/main/java/stirling/software/proprietary/model/api/signature/SavedSignatureResponse.java

@@ -0,0 +1,22 @@
+package stirling.software.proprietary.model.api.signature;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class SavedSignatureResponse {
+    private String id;
+    private String label;
+    private String type; // "canvas", "image", "text"
+    private String scope; // "personal", "shared"
+    private String dataUrl; // For canvas and image types (or URL to fetch image)
+    private String signerName; // For text type
+    private String fontFamily; // For text type
+    private Integer fontSize; // For text type
+    private String textColor; // For text type
+    private Long createdAt;
+    private Long updatedAt;
+}

app/proprietary/src/main/java/stirling/software/proprietary/service/SignatureService.java

@@ -0,0 +1,299 @@
+package stirling.software.proprietary.service;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+import java.util.ArrayList;
+import java.util.Base64;
+import java.util.List;
+import java.util.stream.Stream;
+
+import org.springframework.stereotype.Service;
+
+import lombok.extern.slf4j.Slf4j;
+
+import stirling.software.common.configuration.InstallationPathConfig;
+import stirling.software.common.service.PersonalSignatureServiceInterface;
+import stirling.software.proprietary.model.api.signature.SavedSignatureRequest;
+import stirling.software.proprietary.model.api.signature.SavedSignatureResponse;
+
+/**
+ * Service for managing user signatures with authentication and storage limits. This proprietary
+ * version enforces per-user quotas and requires authentication. Provides access to personal
+ * signatures only (shared signatures handled by core service).
+ */
+@Service
+@Slf4j
+public class SignatureService implements PersonalSignatureServiceInterface {
+
+    private final String SIGNATURE_BASE_PATH;
+    private final String ALL_USERS_FOLDER = "ALL_USERS";
+
+    // Storage limits per user
+    private static final int MAX_SIGNATURES_PER_USER = 20;
+    private static final long MAX_SIGNATURE_SIZE_BYTES = 2_000_000; // 2MB per signature
+    private static final long MAX_TOTAL_USER_STORAGE_BYTES = 20_000_000; // 20MB total per user
+
+    public SignatureService() {
+        SIGNATURE_BASE_PATH = InstallationPathConfig.getSignaturesPath();
+    }
+
+    /**
+     * Get a personal signature from the user's folder only. Does NOT check shared folder (that's
+     * handled by core service).
+     */
+    @Override
+    public byte[] getPersonalSignatureBytes(String username, String fileName) throws IOException {
+        validateFileName(fileName);
+        Path userPath = Paths.get(SIGNATURE_BASE_PATH, username, fileName);
+
+        if (!Files.exists(userPath)) {
+            throw new FileNotFoundException("Personal signature not found");
+        }
+
+        return Files.readAllBytes(userPath);
+    }
+
+    /** Save a signature with storage limits enforced. */
+    public SavedSignatureResponse saveSignature(String username, SavedSignatureRequest request)
+            throws IOException {
+        validateFileName(request.getId());
+
+        // Determine folder based on scope
+        String scope = request.getScope();
+        if (scope == null || scope.isEmpty()) {
+            scope = "personal"; // Default to personal
+        }
+
+        String folderName = "shared".equals(scope) ? ALL_USERS_FOLDER : username;
+        Path targetFolder = Paths.get(SIGNATURE_BASE_PATH, folderName);
+
+        // Only enforce limits for personal signatures (not shared)
+        if ("personal".equals(scope)) {
+            enforceStorageLimits(username, request.getDataUrl());
+        }
+
+        Files.createDirectories(targetFolder);
+
+        long timestamp = System.currentTimeMillis();
+
+        SavedSignatureResponse response = new SavedSignatureResponse();
+        response.setId(request.getId());
+        response.setLabel(request.getLabel());
+        response.setType(request.getType());
+        response.setScope(scope);
+        response.setCreatedAt(timestamp);
+        response.setUpdatedAt(timestamp);
+
+        // Extract and save image data
+        String dataUrl = request.getDataUrl();
+        if (dataUrl != null && dataUrl.startsWith("data:image/")) {
+            // Validate dataUrl size before decoding
+            if (dataUrl.length() > MAX_SIGNATURE_SIZE_BYTES * 2) {
+                throw new IllegalArgumentException(
+                        "Signature data too large (max "
+                                + (MAX_SIGNATURE_SIZE_BYTES / 1024)
+                                + "KB)");
+            }
+
+            // Extract base64 data
+            String base64Data = dataUrl.substring(dataUrl.indexOf(",") + 1);
+            byte[] imageBytes = Base64.getDecoder().decode(base64Data);
+
+            // Validate decoded size
+            if (imageBytes.length > MAX_SIGNATURE_SIZE_BYTES) {
+                throw new IllegalArgumentException(
+                        "Signature image too large (max "
+                                + (MAX_SIGNATURE_SIZE_BYTES / 1024)
+                                + "KB)");
+            }
+
+            // Determine and validate file extension from data URL
+            String mimeType = dataUrl.substring(dataUrl.indexOf(":") + 1, dataUrl.indexOf(";"));
+            String rawExtension = mimeType.substring(mimeType.indexOf("/") + 1);
+            String extension = validateAndNormalizeExtension(rawExtension);
+
+            // Save image file
+            String imageFileName = request.getId() + "." + extension;
+            Path imagePath = targetFolder.resolve(imageFileName);
+
+            // Verify path is within target directory
+            verifyPathWithinDirectory(imagePath, targetFolder);
+
+            Files.write(
+                    imagePath,
+                    imageBytes,
+                    StandardOpenOption.CREATE,
+                    StandardOpenOption.TRUNCATE_EXISTING);
+
+            // Store reference to image file (unified endpoint for all signatures)
+            response.setDataUrl("/api/v1/general/signatures/" + imageFileName);
+        }
+
+        log.info("Saved signature {} for user {} (scope: {})", request.getId(), username, scope);
+        return response;
+    }
+
+    /** Get all saved signatures for a user (personal + shared). */
+    public List<SavedSignatureResponse> getSavedSignatures(String username) throws IOException {
+        List<SavedSignatureResponse> signatures = new ArrayList<>();
+
+        // Load personal signatures
+        Path personalFolder = Paths.get(SIGNATURE_BASE_PATH, username);
+        if (Files.exists(personalFolder)) {
+            signatures.addAll(loadSignaturesFromFolder(personalFolder, "personal", true));
+        }
+
+        // Load shared signatures
+        Path sharedFolder = Paths.get(SIGNATURE_BASE_PATH, ALL_USERS_FOLDER);
+        if (Files.exists(sharedFolder)) {
+            signatures.addAll(loadSignaturesFromFolder(sharedFolder, "shared", false));
+        }
+
+        return signatures;
+    }
+
+    /** Delete a signature from user's personal folder. Cannot delete shared signatures. */
+    public void deleteSignature(String username, String signatureId) throws IOException {
+        validateFileName(signatureId);
+
+        // Only allow deletion from personal folder
+        Path personalFolder = Paths.get(SIGNATURE_BASE_PATH, username);
+        boolean deleted = false;
+
+        if (Files.exists(personalFolder)) {
+            try (Stream<Path> stream = Files.list(personalFolder)) {
+                List<Path> matchingFiles =
+                        stream.filter(
+                                        path ->
+                                                path.getFileName()
+                                                        .toString()
+                                                        .startsWith(signatureId + "."))
+                                .toList();
+                for (Path file : matchingFiles) {
+                    Files.delete(file);
+                    deleted = true;
+                    log.info("Deleted signature file: {}", file);
+                }
+            }
+        }
+
+        if (!deleted) {
+            throw new FileNotFoundException("Signature not found or cannot be deleted");
+        }
+    }
+
+    // Private helper methods
+
+    private void enforceStorageLimits(String username, String dataUrlToAdd) throws IOException {
+        Path userFolder = Paths.get(SIGNATURE_BASE_PATH, username);
+
+        if (!Files.exists(userFolder)) {
+            return; // First signature, no limits to check
+        }
+
+        // Count existing signatures
+        long signatureCount;
+        try (Stream<Path> stream = Files.list(userFolder)) {
+            signatureCount = stream.filter(this::isImageFile).count();
+        }
+
+        if (signatureCount >= MAX_SIGNATURES_PER_USER) {
+            throw new IllegalArgumentException(
+                    "Maximum signatures limit reached (" + MAX_SIGNATURES_PER_USER + ")");
+        }
+
+        // Calculate total storage used
+        long totalSize = 0;
+        try (Stream<Path> stream = Files.list(userFolder)) {
+            totalSize =
+                    stream.filter(this::isImageFile)
+                            .mapToLong(
+                                    path -> {
+                                        try {
+                                            return Files.size(path);
+                                        } catch (IOException e) {
+                                            return 0;
+                                        }
+                                    })
+                            .sum();
+        }
+
+        // Estimate new signature size (base64 decodes to ~75% of original)
+        long estimatedNewSize = (long) (dataUrlToAdd.length() * 0.75);
+
+        if (totalSize + estimatedNewSize > MAX_TOTAL_USER_STORAGE_BYTES) {
+            throw new IllegalArgumentException(
+                    "Storage quota exceeded (max "
+                            + (MAX_TOTAL_USER_STORAGE_BYTES / 1_000_000)
+                            + "MB)");
+        }
+    }
+
+    private List<SavedSignatureResponse> loadSignaturesFromFolder(
+            Path folder, String scope, boolean isPersonal) throws IOException {
+        List<SavedSignatureResponse> signatures = new ArrayList<>();
+
+        try (Stream<Path> stream = Files.list(folder)) {
+            stream.filter(this::isImageFile)
+                    .forEach(
+                            path -> {
+                                try {
+                                    String fileName = path.getFileName().toString();
+                                    String id = fileName.substring(0, fileName.lastIndexOf('.'));
+
+                                    SavedSignatureResponse sig = new SavedSignatureResponse();
+                                    sig.setId(id);
+                                    sig.setLabel(id);
+                                    sig.setType("image");
+                                    sig.setScope(scope);
+                                    sig.setCreatedAt(Files.getLastModifiedTime(path).toMillis());
+                                    sig.setUpdatedAt(Files.getLastModifiedTime(path).toMillis());
+
+                                    // Set unified URL path (works for both personal and shared)
+                                    sig.setDataUrl("/api/v1/general/signatures/" + fileName);
+
+                                    signatures.add(sig);
+                                } catch (IOException e) {
+                                    log.error("Error reading signature file: " + path, e);
+                                }
+                            });
+        }
+
+        return signatures;
+    }
+
+    private boolean isImageFile(Path path) {
+        String fileName = path.getFileName().toString().toLowerCase();
+        return fileName.endsWith(".jpg") || fileName.endsWith(".jpeg") || fileName.endsWith(".png");
+    }
+
+    private void validateFileName(String fileName) {
+        if (fileName.contains("..") || fileName.contains("/") || fileName.contains("\\")) {
+            throw new IllegalArgumentException("Invalid filename");
+        }
+        if (!fileName.matches("^[a-zA-Z0-9_.-]+$")) {
+            throw new IllegalArgumentException("Filename contains invalid characters");
+        }
+    }
+
+    private String validateAndNormalizeExtension(String extension) {
+        String normalized = extension.toLowerCase().trim();
+        if (normalized.equals("png") || normalized.equals("jpg") || normalized.equals("jpeg")) {
+            return normalized;
+        }
+        throw new IllegalArgumentException("Unsupported image extension: " + extension);
+    }
+
+    private void verifyPathWithinDirectory(Path resolvedPath, Path targetDirectory)
+            throws IOException {
+        Path canonicalTarget = targetDirectory.toAbsolutePath().normalize();
+        Path canonicalResolved = resolvedPath.toAbsolutePath().normalize();
+        if (!canonicalResolved.startsWith(canonicalTarget)) {
+            throw new IOException("Resolved path is outside the target directory");
+        }
+    }
+}