Add progress bars, fix DCT decode, sparkly MOTD

Progress bar support (v4.1.2):
- Web frontend: Real-time progress during encode with phase display
- CLI: --progress flag with rich library for encode command
- Backend: progress_file parameter for async progress reporting

DCT decode bug fix:
- Fixed InvalidMagicBytesError not being caught in early-exit check
- RS-protected format (v4.1.0+) has length prefix first, not magic bytes
- Exception handler now catches both ValueError and InvalidMagicBytesError

MOTD update:
- Added sparkly header to setup.sh MOTD (matches other rpi scripts)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontends/cli/main.py

@@ -24,11 +24,31 @@ Usage:
     stegasoo channel [SUBCOMMAND]
 """
 
+import json
 import sys
+import tempfile
+import threading
+import time
+import uuid
 from pathlib import Path
 
 import click
 
+# Rich progress bar (optional)
+try:
+    from rich.progress import (
+        BarColumn,
+        Progress,
+        SpinnerColumn,
+        TaskProgressColumn,
+        TextColumn,
+        TimeElapsedColumn,
+    )
+
+    HAS_RICH = True
+except ImportError:
+    HAS_RICH = False
+
 # Add parent to path for development
 sys.path.insert(0, str(Path(__file__).parent.parent.parent / "src"))
 
@@ -598,6 +618,73 @@ def channel_clear(project, clear_all, force):
         click.echo("  Mode is now: PUBLIC")
 
 
+# ============================================================================
+# PROGRESS BAR UTILITIES (v4.1.2)
+# ============================================================================
+
+
+def _generate_progress_job_id() -> str:
+    """Generate a unique job ID for progress tracking."""
+    return str(uuid.uuid4())[:8]
+
+
+def _get_progress_file_path(job_id: str) -> str:
+    """Get the progress file path for a job ID."""
+    return str(Path(tempfile.gettempdir()) / f"stegasoo_progress_{job_id}.json")
+
+
+def _read_progress(job_id: str) -> dict | None:
+    """Read progress from file for a job ID."""
+    progress_file = _get_progress_file_path(job_id)
+    try:
+        with open(progress_file) as f:
+            return json.load(f)
+    except (FileNotFoundError, json.JSONDecodeError):
+        return None
+
+
+def _cleanup_progress_file(job_id: str) -> None:
+    """Remove progress file for a completed job."""
+    progress_file = _get_progress_file_path(job_id)
+    try:
+        Path(progress_file).unlink(missing_ok=True)
+    except Exception:
+        pass
+
+
+def _run_encode_with_progress(encode_func, encode_kwargs: dict, progress_file: str) -> tuple:
+    """
+    Run encode in a thread and return result.
+
+    Returns:
+        (success, result_or_error)
+    """
+    result_holder = {"result": None, "error": None}
+
+    def run():
+        try:
+            result_holder["result"] = encode_func(**encode_kwargs, progress_file=progress_file)
+        except Exception as e:
+            result_holder["error"] = e
+
+    thread = threading.Thread(target=run)
+    thread.start()
+    return thread, result_holder
+
+
+def _format_phase(phase: str) -> str:
+    """Format phase name for display."""
+    phases = {
+        "starting": "Starting",
+        "initializing": "Initializing",
+        "embedding": "Embedding",
+        "saving": "Saving",
+        "finalizing": "Finalizing",
+        "complete": "Complete",
+    }
+    return phases.get(phase, phase.capitalize())
+
+
 # ============================================================================
 # ENCODE COMMAND
 # ============================================================================
@@ -642,6 +729,7 @@ def channel_clear(project, clear_all, force):
     help="DCT color mode: grayscale (default) or color (preserves original colors)",
 )
 @click.option("--quiet", "-q", is_flag=True, help="Suppress output except errors")
+@click.option("--progress", is_flag=True, help="Show progress bar (requires rich)")
 def encode_cmd(
     ref,
     carrier,
@@ -661,6 +749,7 @@ def encode_cmd(
     dct_output_format,
     dct_color_mode,
     quiet,
+    progress,
 ):
     """
     Encode a secret message or file into an image.
@@ -808,19 +897,63 @@ def encode_cmd(
                 click.echo(channel_status)
 
         # v4.0.0: Include channel_key parameter
-        result = encode(
+        # v4.1.2: Progress bar support
-            message=payload,
+        encode_kwargs = {
-            reference_photo=ref_photo,
+            "message": payload,
-            carrier_image=carrier_image,
+            "reference_photo": ref_photo,
-            passphrase=passphrase,
+            "carrier_image": carrier_image,
-            pin=pin or "",
+            "passphrase": passphrase,
-            rsa_key_data=rsa_key_data,
+            "pin": pin or "",
-            rsa_password=effective_key_password,
+            "rsa_key_data": rsa_key_data,
-            embed_mode=embed_mode,
+            "rsa_password": effective_key_password,
-            dct_output_format=dct_output_format,
+            "embed_mode": embed_mode,
-            dct_color_mode=dct_color_mode,
+            "dct_output_format": dct_output_format,
-            channel_key=resolved_channel_key,
+            "dct_color_mode": dct_color_mode,
+            "channel_key": resolved_channel_key,
+        }
+
+        if progress and HAS_RICH:
+            # Run with progress bar
+            job_id = _generate_progress_job_id()
+            progress_file = _get_progress_file_path(job_id)
+
+            thread, result_holder = _run_encode_with_progress(encode, encode_kwargs, progress_file)
+
+            with Progress(
+                SpinnerColumn(),
+                TextColumn("[progress.description]{task.description}"),
+                BarColumn(),
+                TaskProgressColumn(),
+                TimeElapsedColumn(),
+                transient=True,
+            ) as progress_bar:
+                task = progress_bar.add_task("Encoding...", total=100)
+
+                while thread.is_alive():
+                    prog = _read_progress(job_id)
+                    if prog:
+                        percent = prog.get("percent", 0)
+                        phase = _format_phase(prog.get("phase", "processing"))
+                        progress_bar.update(task, completed=percent, description=f"{phase}...")
+                    time.sleep(0.1)
+
+                # Final update
+                progress_bar.update(task, completed=100, description="Complete!")
+
+            _cleanup_progress_file(job_id)
+
+            if result_holder["error"]:
+                raise result_holder["error"]
+            result = result_holder["result"]
+
+        elif progress and not HAS_RICH:
+            click.secho(
+                "Warning: --progress requires 'rich' package. Install with: pip install rich",
+                fg="yellow",
             )
+            result = encode(**encode_kwargs)
+        else:
+            result = encode(**encode_kwargs)
 
         # Determine output path
         if output:

frontends/web/app.py

@@ -26,7 +26,9 @@ import mimetypes
 import os
 import secrets
 import sys
+import threading
 import time
+from concurrent.futures import ThreadPoolExecutor
 from pathlib import Path
 
 from auth import (
@@ -36,6 +38,7 @@ from auth import (
     can_create_user,
     can_save_channel_key,
     change_password,
+    clear_recovery_key,
     create_admin_user,
     create_user,
     delete_channel_key,
@@ -45,12 +48,11 @@ from auth import (
     get_channel_key_by_id,
     get_current_user,
     get_non_admin_count,
+    get_recovery_key_hash,
     get_user_by_id,
     get_user_channel_keys,
     get_username,
     has_recovery_key,
-    get_recovery_key_hash,
-    clear_recovery_key,
     is_admin,
     is_authenticated,
     login_required,
@@ -59,10 +61,10 @@ from auth import (
     reset_user_password,
     save_channel_key,
     set_recovery_key_hash,
-    verify_and_reset_admin_password,
     update_channel_key_last_used,
     update_channel_key_name,
     user_exists,
+    verify_and_reset_admin_password,
     verify_user_password,
 )
 from auth import (
@@ -156,7 +158,13 @@ except ImportError:
 # ============================================================================
 # Runs encode/decode/compare in subprocesses to prevent jpegio/scipy crashes
 # from taking down the Flask server.
-from subprocess_stego import SubprocessStego
+from subprocess_stego import (
+    SubprocessStego,
+    cleanup_progress_file,
+    generate_job_id,
+    get_progress_file_path,
+    read_progress,
+)
 
 from stegasoo.qr_utils import (
     can_fit_in_qr,
@@ -195,6 +203,42 @@ app.config["HTTPS_ENABLED"] = os.environ.get("STEGASOO_HTTPS_ENABLED", "false").
 # Initialize auth module
 init_auth(app)
 
+# ============================================================================
+# ASYNC JOB MANAGEMENT (v4.1.2)
+# ============================================================================
+# Encode operations can run in background threads with progress reporting
+
+# Thread pool for background encode/decode operations
+_executor = ThreadPoolExecutor(max_workers=2)
+
+# Job storage: job_id -> {status, result, error, file_id, ...}
+_jobs = {}
+_jobs_lock = threading.Lock()
+
+
+def _store_job(job_id: str, data: dict) -> None:
+    """Thread-safe job storage."""
+    with _jobs_lock:
+        _jobs[job_id] = data
+
+
+def _get_job(job_id: str) -> dict | None:
+    """Thread-safe job retrieval."""
+    with _jobs_lock:
+        return _jobs.get(job_id)
+
+
+def _cleanup_old_jobs(max_age_seconds: int = 3600) -> None:
+    """Remove jobs older than max_age_seconds."""
+    now = time.time()
+    with _jobs_lock:
+        to_remove = [
+            jid for jid, data in _jobs.items() if now - data.get("created", 0) > max_age_seconds
+        ]
+        for jid in to_remove:
+            cleanup_progress_file(jid)
+            del _jobs[jid]
+
 
 @app.before_request
 def require_setup():
@@ -817,10 +861,119 @@ def api_check_fit():
 # ============================================================================
 
 
+def _run_encode_job(job_id: str, encode_params: dict) -> None:
+    """Background thread function for async encode."""
+    progress_file = get_progress_file_path(job_id)
+
+    try:
+        _store_job(job_id, {"status": "running", "created": time.time()})
+
+        # Run encode with progress file
+        if encode_params.get("file_data"):
+            encode_result = subprocess_stego.encode(
+                carrier_data=encode_params["carrier_data"],
+                reference_data=encode_params["ref_data"],
+                file_data=encode_params["file_data"],
+                file_name=encode_params["file_name"],
+                file_mime=encode_params["file_mime"],
+                passphrase=encode_params["passphrase"],
+                pin=encode_params.get("pin"),
+                rsa_key_data=encode_params.get("rsa_key_data"),
+                rsa_password=encode_params.get("key_password"),
+                embed_mode=encode_params["embed_mode"],
+                dct_output_format=encode_params.get("dct_output_format", "png"),
+                dct_color_mode=encode_params.get("dct_color_mode", "color"),
+                channel_key=encode_params.get("channel_key"),
+                progress_file=progress_file,
+            )
+        else:
+            encode_result = subprocess_stego.encode(
+                carrier_data=encode_params["carrier_data"],
+                reference_data=encode_params["ref_data"],
+                message=encode_params["message"],
+                passphrase=encode_params["passphrase"],
+                pin=encode_params.get("pin"),
+                rsa_key_data=encode_params.get("rsa_key_data"),
+                rsa_password=encode_params.get("key_password"),
+                embed_mode=encode_params["embed_mode"],
+                dct_output_format=encode_params.get("dct_output_format", "png"),
+                dct_color_mode=encode_params.get("dct_color_mode", "color"),
+                channel_key=encode_params.get("channel_key"),
+                progress_file=progress_file,
+            )
+
+        if not encode_result.success:
+            _store_job(
+                job_id,
+                {
+                    "status": "error",
+                    "error": encode_result.error or "Encoding failed",
+                    "created": time.time(),
+                },
+            )
+            return
+
+        # Determine output format
+        embed_mode = encode_params["embed_mode"]
+        dct_output_format = encode_params.get("dct_output_format", "png")
+        dct_color_mode = encode_params.get("dct_color_mode", "color")
+
+        if embed_mode == "dct" and dct_output_format == "jpeg":
+            output_ext = ".jpg"
+            output_mime = "image/jpeg"
+        else:
+            output_ext = ".png"
+            output_mime = "image/png"
+
+        filename = encode_result.filename
+        if not filename:
+            filename = generate_filename("stego", output_ext)
+        elif embed_mode == "dct" and dct_output_format == "jpeg" and filename.endswith(".png"):
+            filename = filename[:-4] + ".jpg"
+
+        # Store result
+        file_id = secrets.token_urlsafe(16)
+        TEMP_FILES[file_id] = {
+            "data": encode_result.stego_data,
+            "filename": filename,
+            "timestamp": time.time(),
+            "embed_mode": embed_mode,
+            "output_format": dct_output_format if embed_mode == "dct" else "png",
+            "color_mode": dct_color_mode if embed_mode == "dct" else None,
+            "mime_type": output_mime,
+            "channel_mode": encode_result.channel_mode,
+            "channel_fingerprint": encode_result.channel_fingerprint,
+        }
+
+        _store_job(
+            job_id,
+            {
+                "status": "complete",
+                "file_id": file_id,
+                "created": time.time(),
+            },
+        )
+
+    except Exception as e:
+        _store_job(
+            job_id,
+            {
+                "status": "error",
+                "error": str(e),
+                "created": time.time(),
+            },
+        )
+    finally:
+        cleanup_progress_file(job_id)
+
+
 @app.route("/encode", methods=["GET", "POST"])
 @login_required
 def encode_page():
     if request.method == "POST":
+        # Check if async mode requested
+        is_async = request.form.get("async") == "true" or request.headers.get("X-Async") == "true"
+
         try:
             # Get files
             ref_photo = request.files.get("reference_photo")
@@ -956,7 +1109,9 @@ def encode_page():
             # Pre-check payload capacity BEFORE encode (fail fast)
             from stegasoo.steganography import will_fit_by_mode
 
-            payload_size = len(payload.data) if hasattr(payload, "data") else len(payload.encode("utf-8"))
+            payload_size = (
+                len(payload.data) if hasattr(payload, "data") else len(payload.encode("utf-8"))
+            )
             fit_check = will_fit_by_mode(payload_size, carrier_data, embed_mode=embed_mode)
             if not fit_check.get("fits", True):
                 error_msg = (
@@ -972,8 +1127,35 @@ def encode_page():
                 flash(error_msg, "error")
                 return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
 
-            # v4.0.0: Include channel_key parameter
+            # Build encode params for either sync or async
-            # Use subprocess-isolated encode to prevent crashes
+            encode_params = {
+                "carrier_data": carrier_data,
+                "ref_data": ref_data,
+                "passphrase": passphrase,
+                "pin": pin if pin else None,
+                "rsa_key_data": rsa_key_data,
+                "key_password": key_password,
+                "embed_mode": embed_mode,
+                "dct_output_format": dct_output_format if embed_mode == "dct" else "png",
+                "dct_color_mode": dct_color_mode if embed_mode == "dct" else "color",
+                "channel_key": channel_key,
+            }
+
+            if payload_type == "file" and payload_file and payload_file.filename:
+                encode_params["file_data"] = payload.data
+                encode_params["file_name"] = payload.filename
+                encode_params["file_mime"] = payload.mime_type
+            else:
+                encode_params["message"] = payload
+
+            # ASYNC MODE: Start background job and return JSON
+            if is_async:
+                job_id = generate_job_id()
+                _store_job(job_id, {"status": "pending", "created": time.time()})
+                _executor.submit(_run_encode_job, job_id, encode_params)
+                return jsonify({"job_id": job_id, "status": "pending"})
+
+            # SYNC MODE: Run inline (original behavior)
             if payload_type == "file" and payload_file and payload_file.filename:
                 encode_result = subprocess_stego.encode(
                     carrier_data=carrier_data,
@@ -988,7 +1170,7 @@ def encode_page():
                     embed_mode=embed_mode,
                     dct_output_format=dct_output_format if embed_mode == "dct" else "png",
                     dct_color_mode=dct_color_mode if embed_mode == "dct" else "color",
-                    channel_key=channel_key,  # v4.0.0
+                    channel_key=channel_key,
                 )
             else:
                 encode_result = subprocess_stego.encode(
@@ -1002,7 +1184,7 @@ def encode_page():
                     embed_mode=embed_mode,
                     dct_output_format=dct_output_format if embed_mode == "dct" else "png",
                     dct_color_mode=dct_color_mode if embed_mode == "dct" else "color",
-                    channel_key=channel_key,  # v4.0.0
+                    channel_key=channel_key,
                 )
 
             # Check for subprocess errors
@@ -1058,6 +1240,53 @@ def encode_page():
     return render_template("encode.html", has_qrcode_read=HAS_QRCODE_READ)
 
 
+# ============================================================================
+# ENCODE PROGRESS ENDPOINTS (v4.1.2)
+# ============================================================================
+
+
+@app.route("/encode/status/<job_id>")
+@login_required
+def encode_status(job_id):
+    """Get the status of an async encode job."""
+    job = _get_job(job_id)
+    if not job:
+        return jsonify({"error": "Job not found"}), 404
+
+    response = {"status": job.get("status", "unknown")}
+
+    if job["status"] == "complete":
+        response["file_id"] = job.get("file_id")
+    elif job["status"] == "error":
+        response["error"] = job.get("error", "Unknown error")
+
+    return jsonify(response)
+
+
+@app.route("/encode/progress/<job_id>")
+@login_required
+def encode_progress(job_id):
+    """Get the progress of an async encode job."""
+    progress = read_progress(job_id)
+    if progress:
+        return jsonify(progress)
+
+    # No progress file yet - check job status
+    job = _get_job(job_id)
+    if not job:
+        return jsonify({"error": "Job not found"}), 404
+
+    if job["status"] == "complete":
+        return jsonify({"percent": 100, "phase": "complete"})
+    elif job["status"] == "error":
+        return jsonify({"percent": 0, "phase": "error", "error": job.get("error")})
+    elif job["status"] == "pending":
+        return jsonify({"percent": 0, "phase": "starting"})
+
+    # Running but no progress file yet
+    return jsonify({"percent": 0, "phase": "initializing"})
+
+
 @app.route("/encode/result/<file_id>")
 @login_required
 def encode_result(file_id):
@@ -1402,12 +1631,7 @@ def api_tools_strip_metadata():
         buffer = io.BytesIO(clean_data)
         filename = image_file.filename.rsplit(".", 1)[0] + "_clean.png"
 
-        return send_file(
+        return send_file(buffer, mimetype="image/png", as_attachment=True, download_name=filename)
-            buffer,
-            mimetype="image/png",
-            as_attachment=True,
-            download_name=filename
-        )
     except Exception as e:
         return jsonify({"success": False, "error": str(e)}), 400
 
@@ -1429,13 +1653,15 @@ def api_tools_exif():
         # Check if it's a JPEG (editable) or not
         is_jpeg = image_data[:2] == b"\xff\xd8"
 
-        return jsonify({
+        return jsonify(
+            {
                 "success": True,
                 "filename": image_file.filename,
                 "exif": exif,
                 "editable": is_jpeg,
                 "field_count": len(exif),
-        })
+            }
+        )
     except Exception as e:
         return jsonify({"success": False, "error": str(e)}), 400
 
@@ -1454,6 +1680,7 @@ def api_tools_exif_update():
     updates_json = request.form.get("updates", "{}")
     try:
         import json
+
         updates = json.loads(updates_json)
     except json.JSONDecodeError:
         return jsonify({"success": False, "error": "Invalid updates JSON"}), 400
@@ -1499,11 +1726,19 @@ def api_tools_exif_clear():
         clean_data = strip_image_metadata(image_data, output_format=output_format)
 
         # Determine extension and mimetype
-        ext_map = {"PNG": ("png", "image/png"), "JPEG": ("jpg", "image/jpeg"), "BMP": ("bmp", "image/bmp")}
+        ext_map = {
+            "PNG": ("png", "image/png"),
+            "JPEG": ("jpg", "image/jpeg"),
+            "BMP": ("bmp", "image/bmp"),
+        }
         ext, mimetype = ext_map.get(output_format, ("png", "image/png"))
 
         # Return as downloadable file
-        stem = image_file.filename.rsplit(".", 1)[0] if "." in image_file.filename else image_file.filename
+        stem = (
+            image_file.filename.rsplit(".", 1)[0]
+            if "." in image_file.filename
+            else image_file.filename
+        )
         buffer = io.BytesIO(clean_data)
         return send_file(
             buffer,
@@ -1644,9 +1879,10 @@ def setup():
 @login_required
 def setup_recovery():
     """Recovery key setup page (Step 2 of initial setup)."""
-    from stegasoo.recovery import generate_recovery_key, hash_recovery_key, generate_recovery_qr
     import base64
 
+    from stegasoo.recovery import generate_recovery_key, generate_recovery_qr, hash_recovery_key
+
     # Only allow during initial setup (no recovery key yet, first admin)
     if has_recovery_key():
         return redirect(url_for("index"))
@@ -1724,9 +1960,10 @@ def recover():
 @admin_required
 def regenerate_recovery():
     """Generate a new recovery key (replaces existing one)."""
-    from stegasoo.recovery import generate_recovery_key, hash_recovery_key, generate_recovery_qr
     import base64
 
+    from stegasoo.recovery import generate_recovery_key, generate_recovery_qr, hash_recovery_key
+
     if request.method == "POST":
         action = request.form.get("action")
 
@@ -1925,7 +2162,8 @@ def api_channel_keys():
     """Get saved channel keys for current user (JSON API)."""
     current_user = get_current_user()
     keys = get_user_channel_keys(current_user.id)
-    return jsonify({
+    return jsonify(
+        {
             "success": True,
             "keys": [
                 {
@@ -1939,7 +2177,8 @@ def api_channel_keys():
             ],
             "can_save": can_save_channel_key(current_user.id),
             "max_keys": MAX_CHANNEL_KEYS,
-    })
+        }
+    )
 
 
 @app.route("/api/channel/keys/<int:key_id>/use", methods=["POST"])

frontends/web/static/js/stegasoo.js

@@ -916,6 +916,180 @@ const Stegasoo = {
         });
     },
     
+    // ========================================================================
+    // ASYNC ENCODE WITH PROGRESS (v4.1.2)
+    // ========================================================================
+
+    /**
+     * Submit encode form asynchronously with progress tracking
+     * @param {HTMLFormElement} form - The encode form
+     * @param {HTMLElement} btn - The submit button
+     */
+    async submitEncodeAsync(form, btn) {
+        const formData = new FormData(form);
+        formData.append('async', 'true');
+
+        // Show progress modal
+        this.showProgressModal('Encoding');
+
+        try {
+            // Start encode job
+            const response = await fetch('/encode', {
+                method: 'POST',
+                body: formData,
+            });
+
+            if (!response.ok) {
+                throw new Error('Failed to start encode');
+            }
+
+            const result = await response.json();
+
+            if (result.error) {
+                throw new Error(result.error);
+            }
+
+            const jobId = result.job_id;
+
+            // Poll for progress
+            await this.pollEncodeProgress(jobId);
+
+        } catch (error) {
+            this.hideProgressModal();
+            alert('Encode failed: ' + error.message);
+            btn.disabled = false;
+            btn.innerHTML = '<i class="bi bi-lock-fill me-2"></i>Encode';
+        }
+    },
+
+    /**
+     * Poll encode progress until complete
+     * @param {string} jobId - The job ID
+     */
+    async pollEncodeProgress(jobId) {
+        const progressBar = document.getElementById('progressBar');
+        const progressText = document.getElementById('progressText');
+        const phaseText = document.getElementById('progressPhase');
+
+        const poll = async () => {
+            try {
+                // Check status first
+                const statusResponse = await fetch(`/encode/status/${jobId}`);
+                const statusData = await statusResponse.json();
+
+                if (statusData.status === 'complete') {
+                    // Done - redirect to result
+                    this.updateProgress(100, 'Complete!');
+                    setTimeout(() => {
+                        window.location.href = `/encode/result/${statusData.file_id}`;
+                    }, 500);
+                    return;
+                }
+
+                if (statusData.status === 'error') {
+                    throw new Error(statusData.error || 'Encode failed');
+                }
+
+                // Get progress
+                const progressResponse = await fetch(`/encode/progress/${jobId}`);
+                const progressData = await progressResponse.json();
+
+                const percent = progressData.percent || 0;
+                const phase = progressData.phase || 'processing';
+
+                this.updateProgress(percent, this.formatPhase(phase));
+
+                // Continue polling
+                setTimeout(poll, 500);
+
+            } catch (error) {
+                this.hideProgressModal();
+                alert('Encode failed: ' + error.message);
+            }
+        };
+
+        await poll();
+    },
+
+    /**
+     * Format phase name for display
+     */
+    formatPhase(phase) {
+        const phases = {
+            'starting': 'Starting...',
+            'initializing': 'Initializing...',
+            'embedding': 'Embedding data...',
+            'saving': 'Saving image...',
+            'finalizing': 'Finalizing...',
+            'complete': 'Complete!',
+        };
+        return phases[phase] || phase;
+    },
+
+    /**
+     * Show progress modal
+     */
+    showProgressModal(operation = 'Processing') {
+        // Create modal if doesn't exist
+        let modal = document.getElementById('progressModal');
+        if (!modal) {
+            modal = document.createElement('div');
+            modal.id = 'progressModal';
+            modal.className = 'modal fade';
+            modal.setAttribute('data-bs-backdrop', 'static');
+            modal.setAttribute('data-bs-keyboard', 'false');
+            modal.innerHTML = `
+                <div class="modal-dialog modal-dialog-centered">
+                    <div class="modal-content bg-dark text-light">
+                        <div class="modal-body p-4">
+                            <h5 class="mb-3" id="progressTitle">${operation}...</h5>
+                            <div class="progress mb-2" style="height: 24px;">
+                                <div id="progressBar" class="progress-bar progress-bar-striped progress-bar-animated bg-success"
+                                     role="progressbar" style="width: 0%"></div>
+                            </div>
+                            <div class="d-flex justify-content-between text-muted small">
+                                <span id="progressPhase">Initializing...</span>
+                                <span id="progressText">0%</span>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+            `;
+            document.body.appendChild(modal);
+        }
+
+        // Reset progress
+        this.updateProgress(0, 'Initializing...');
+
+        // Show modal
+        const bsModal = new bootstrap.Modal(modal);
+        bsModal.show();
+    },
+
+    /**
+     * Hide progress modal
+     */
+    hideProgressModal() {
+        const modal = document.getElementById('progressModal');
+        if (modal) {
+            const bsModal = bootstrap.Modal.getInstance(modal);
+            bsModal?.hide();
+        }
+    },
+
+    /**
+     * Update progress bar and text
+     */
+    updateProgress(percent, phase) {
+        const progressBar = document.getElementById('progressBar');
+        const progressText = document.getElementById('progressText');
+        const phaseText = document.getElementById('progressPhase');
+
+        if (progressBar) progressBar.style.width = percent + '%';
+        if (progressText) progressText.textContent = Math.round(percent) + '%';
+        if (phaseText) phaseText.textContent = phase;
+    },
+
     // ========================================================================
     // INITIALIZATION HELPERS
     // ========================================================================
@@ -937,27 +1111,23 @@ const Stegasoo = {
             generateBtnId: 'channelKeyGenerate'
         });
 
-        // Form submission with channel key validation
+        // Form submission with async progress tracking (v4.1.2)
         const form = document.getElementById('encodeForm');
         const btn = document.getElementById('encodeBtn');
         form?.addEventListener('submit', (e) => {
-            if (!this.validateChannelKeyOnSubmit(form, 'channelSelect', 'channelKeyInput')) {
             e.preventDefault();
+
+            if (!this.validateChannelKeyOnSubmit(form, 'channelSelect', 'channelKeyInput')) {
                 return false;
             }
+
             if (btn) {
                 btn.disabled = true;
-                const startTime = Date.now();
+                btn.innerHTML = '<span class="spinner-border spinner-border-sm me-2"></span>Starting...';
-                const updateTimer = () => {
-                    const elapsed = Math.floor((Date.now() - startTime) / 1000);
-                    const mins = Math.floor(elapsed / 60);
-                    const secs = elapsed % 60;
-                    const timeStr = mins > 0 ? `${mins}:${secs.toString().padStart(2, '0')}` : `${secs}s`;
-                    btn.innerHTML = `<span class="spinner-border spinner-border-sm me-2"></span>Encoding... ${timeStr}`;
-                };
-                updateTimer();
-                setInterval(updateTimer, 1000);
             }
+
+            // Use async submission with progress tracking
+            this.submitEncodeAsync(form, btn);
         });
     },
     

frontends/web/stego_worker.py

@@ -111,6 +111,7 @@ def encode_operation(params: dict) -> dict:
         dct_output_format=params.get("dct_output_format", "png"),
         dct_color_mode=params.get("dct_color_mode", "color"),
         channel_key=resolved_channel_key,  # v4.0.0
+        progress_file=params.get("progress_file"),  # v4.1.2
     )
 
     # Build stats dict if available

frontends/web/subprocess_stego.py

@@ -47,6 +47,8 @@ import base64
 import json
 import subprocess
 import sys
+import tempfile
+import uuid
 from dataclasses import dataclass
 from pathlib import Path
 from typing import Any
@@ -233,6 +235,8 @@ class SubprocessStego:
         # Channel key (v4.0.0)
         channel_key: str | None = "auto",
         timeout: int | None = None,
+        # Progress file (v4.1.2)
+        progress_file: str | None = None,
     ) -> EncodeResult:
         """
         Encode a message or file into an image.
@@ -268,6 +272,7 @@ class SubprocessStego:
             "dct_output_format": dct_output_format,
             "dct_color_mode": dct_color_mode,
             "channel_key": channel_key,  # v4.0.0
+            "progress_file": progress_file,  # v4.1.2
         }
 
         if file_data:
@@ -496,3 +501,42 @@ def get_subprocess_stego() -> SubprocessStego:
     if _default_stego is None:
         _default_stego = SubprocessStego()
     return _default_stego
+
+
+# =============================================================================
+# Progress File Utilities (v4.1.2)
+# =============================================================================
+
+
+def generate_job_id() -> str:
+    """Generate a unique job ID for tracking encode/decode operations."""
+    return str(uuid.uuid4())[:8]
+
+
+def get_progress_file_path(job_id: str) -> str:
+    """Get the progress file path for a job ID."""
+    return str(Path(tempfile.gettempdir()) / f"stegasoo_progress_{job_id}.json")
+
+
+def read_progress(job_id: str) -> dict | None:
+    """
+    Read progress from file for a job ID.
+
+    Returns:
+        Progress dict with current, total, percent, phase, or None if not found
+    """
+    progress_file = get_progress_file_path(job_id)
+    try:
+        with open(progress_file) as f:
+            return json.load(f)
+    except (FileNotFoundError, json.JSONDecodeError):
+        return None
+
+
+def cleanup_progress_file(job_id: str) -> None:
+    """Remove progress file for a completed job."""
+    progress_file = get_progress_file_path(job_id)
+    try:
+        Path(progress_file).unlink(missing_ok=True)
+    except Exception:
+        pass

pyproject.toml

@@ -54,6 +54,7 @@ cli = [
     "click>=8.0.0",
     "qrcode>=7.30",
     "piexif>=1.1.0",
+    "rich>=13.0.0",
 ]
 compression = [
     "lz4>=4.0.0",

rpi/setup.sh

@@ -335,11 +335,14 @@ if systemctl is-active --quiet stegasoo 2>/dev/null; then
         STEGASOO_URL="http://$PI_IP:5000"
     fi
     echo ""
+    echo -e "\033[0;90m    .  *  .   .    *    .   *   .  *   .    *   .\033[0m"
     echo -e "\033[0;36m   ___  _____  ___    ___    _    ___    ___    ___\033[0m"
     echo -e "\033[0;36m  / __||_   _|| __|  / __|  /_\\  / __|  / _ \\  / _ \\\\\033[0m"
     echo -e "\033[0;36m  \\__ \\  | |  | _|  | (_ | / _ \\ \\__ \\ | (_) || (_) |\033[0m"
     echo -e "\033[0;36m  |___/  |_|  |___|  \\___//_/ \\_\\|___/  \\___/  \\___/\033[0m"
     echo ""
+    echo -e "\033[0;90m    *    .   *   .    *    .   *   .    *   .   *\033[0m"
+    echo ""
     echo -e " \033[0;32m●\033[0m Stegasoo is running"
     echo -e "   \033[0;33m$STEGASOO_URL\033[0m"
     echo ""

src/stegasoo/dct_steganography.py

@@ -55,7 +55,32 @@ except ImportError:
     jio = None
 
 # Import custom exceptions
-from .exceptions import InvalidMagicBytesError, ReedSolomonError as StegasooRSError
+from .exceptions import InvalidMagicBytesError
+from .exceptions import ReedSolomonError as StegasooRSError
+
+# Progress reporting interval (write every N blocks)
+PROGRESS_INTERVAL = 50
+
+
+def _write_progress(progress_file: str | None, current: int, total: int, phase: str = "embedding"):
+    """Write progress to file for frontend polling."""
+    if progress_file is None:
+        return
+    try:
+        import json
+
+        with open(progress_file, "w") as f:
+            json.dump(
+                {
+                    "current": current,
+                    "total": total,
+                    "percent": round((current / total) * 100, 1) if total > 0 else 0,
+                    "phase": phase,
+                },
+                f,
+            )
+    except Exception:
+        pass  # Don't let progress writing break encoding
 
 
 # ============================================================================
@@ -189,7 +214,7 @@ def has_jpegio_support() -> bool:
 
 # Check for reedsolo availability
 try:
-    from reedsolo import RSCodec, ReedSolomonError
+    from reedsolo import ReedSolomonError, RSCodec
 
     HAS_REEDSOLO = True
 except ImportError:
@@ -559,6 +584,7 @@ def embed_in_dct(
     seed: bytes,
     output_format: str = OUTPUT_FORMAT_PNG,
     color_mode: str = "color",
+    progress_file: str | None = None,
 ) -> tuple[bytes, DCTEmbedStats]:
     """Embed data using DCT coefficient modification."""
     if output_format not in (OUTPUT_FORMAT_PNG, OUTPUT_FORMAT_JPEG):
@@ -568,10 +594,12 @@ def embed_in_dct(
         color_mode = "color"
 
     if output_format == OUTPUT_FORMAT_JPEG and HAS_JPEGIO:
-        return _embed_jpegio(data, carrier_image, seed, color_mode)
+        return _embed_jpegio(data, carrier_image, seed, color_mode, progress_file)
 
     _check_scipy()
-    return _embed_scipy_dct_safe(data, carrier_image, seed, output_format, color_mode)
+    return _embed_scipy_dct_safe(
+        data, carrier_image, seed, output_format, color_mode, progress_file
+    )
 
 
 def _embed_scipy_dct_safe(
@@ -580,6 +608,7 @@ def _embed_scipy_dct_safe(
     seed: bytes,
     output_format: str,
     color_mode: str = "color",
+    progress_file: str | None = None,
 ) -> tuple[bytes, DCTEmbedStats]:
     """
     Embed using scipy DCT with safe memory handling.
@@ -642,7 +671,7 @@ def _embed_scipy_dct_safe(
         gc.collect()
 
         # Embed in Y channel
-        Y_embedded = _embed_in_channel_safe(Y_padded, bits, block_order, blocks_x)
+        Y_embedded = _embed_in_channel_safe(Y_padded, bits, block_order, blocks_x, progress_file)
         del Y_padded
         gc.collect()
 
@@ -666,7 +695,7 @@ def _embed_scipy_dct_safe(
         del image
         gc.collect()
 
-        embedded = _embed_in_channel_safe(padded, bits, block_order, blocks_x)
+        embedded = _embed_in_channel_safe(padded, bits, block_order, blocks_x, progress_file)
         del padded
         gc.collect()
 
@@ -699,6 +728,7 @@ def _embed_in_channel_safe(
     bits: list,
     block_order: list,
     blocks_x: int,
+    progress_file: str | None = None,
 ) -> np.ndarray:
     """
     Embed bits in channel using safe DCT operations.
@@ -711,8 +741,9 @@ def _embed_in_channel_safe(
     result = np.array(channel, dtype=np.float64, copy=True, order="C")
 
     bit_idx = 0
+    total_blocks = len(block_order)
 
-    for block_num in block_order:
+    for block_idx, block_num in enumerate(block_order):
         if bit_idx >= len(bits):
             break
 
@@ -748,6 +779,14 @@ def _embed_in_channel_safe(
         # Clean up this iteration
         del block, dct_block, modified_block
 
+        # Report progress periodically
+        if progress_file and block_idx % PROGRESS_INTERVAL == 0:
+            _write_progress(progress_file, block_idx, total_blocks, "embedding")
+
+    # Final progress update
+    if progress_file:
+        _write_progress(progress_file, total_blocks, total_blocks, "finalizing")
+
     # Force garbage collection
     gc.collect()
 
@@ -804,6 +843,7 @@ def _embed_jpegio(
     carrier_image: bytes,
     seed: bytes,
     color_mode: str = "color",
+    progress_file: str | None = None,
 ) -> tuple[bytes, DCTEmbedStats]:
     """Embed using jpegio for proper JPEG coefficient modification."""
     import os
@@ -861,6 +901,9 @@ def _embed_jpegio(
             )
 
         coefs_used = 0
+        total_bits = len(bits)
+        progress_interval = max(total_bits // 20, 100)  # Report ~20 times or every 100 bits
+
         for bit_idx, pos_idx in enumerate(order):
             if bit_idx >= len(bits):
                 break
@@ -876,6 +919,14 @@ def _embed_jpegio(
 
             coefs_used += 1
 
+            # Report progress periodically
+            if progress_file and bit_idx % progress_interval == 0:
+                _write_progress(progress_file, bit_idx, total_bits, "embedding")
+
+        # Final progress before save
+        if progress_file:
+            _write_progress(progress_file, total_bits, total_bits, "saving")
+
         jio.write(jpeg, output_path)
 
         with open(output_path, "rb") as f:
@@ -971,8 +1022,8 @@ def _extract_scipy_dct_safe(stego_image: bytes, seed: bytes) -> bytes:
                 total_needed = (HEADER_SIZE + data_length) * 8
                 if len(all_bits) >= total_needed:
                     break
-            except ValueError:
+            except (ValueError, InvalidMagicBytesError):
-                pass
+                pass  # RS-protected format has length prefix first, not magic bytes
 
     del padded
     gc.collect()
@@ -997,6 +1048,7 @@ def _extract_scipy_dct_safe(stego_image: bytes, seed: bytes) -> bytes:
 
         # Count occurrences of each unique copy
         from collections import Counter
+
         counter = Counter(copies)
         best_header, count = counter.most_common(1)[0]
 
@@ -1009,9 +1061,13 @@ def _extract_scipy_dct_safe(stego_image: bytes, seed: bytes) -> bytes:
 
         # Sanity check: both lengths should be reasonable
         max_reasonable = (len(all_bits) // 8) - RS_LENGTH_PREFIX_SIZE
-        if (raw_payload_length > 0 and raw_payload_length <= max_reasonable and
+        if (
-            rs_encoded_length > 0 and rs_encoded_length <= max_reasonable and
+            raw_payload_length > 0
-            rs_encoded_length >= raw_payload_length):
+            and raw_payload_length <= max_reasonable
+            and rs_encoded_length > 0
+            and rs_encoded_length <= max_reasonable
+            and rs_encoded_length >= raw_payload_length
+        ):
             # This looks like RS-protected format
             total_bits_needed = (RS_LENGTH_PREFIX_SIZE + rs_encoded_length) * 8
 
@@ -1088,6 +1144,7 @@ def _extract_jpegio(stego_image: bytes, seed: bytes) -> bytes:
 
             # Extract 3 copies and use majority voting
             from collections import Counter
+
             copies = []
             for i in range(RS_LENGTH_COPIES):
                 start = i * RS_LENGTH_HEADER_SIZE
@@ -1104,9 +1161,13 @@ def _extract_jpegio(stego_image: bytes, seed: bytes) -> bytes:
 
             # Sanity check
             max_reasonable = (len(all_positions) // 8) - RS_LENGTH_PREFIX_SIZE
-            if (raw_payload_length > 0 and raw_payload_length <= max_reasonable and
+            if (
-                rs_encoded_length > 0 and rs_encoded_length <= max_reasonable and
+                raw_payload_length > 0
-                rs_encoded_length >= raw_payload_length):
+                and raw_payload_length <= max_reasonable
+                and rs_encoded_length > 0
+                and rs_encoded_length <= max_reasonable
+                and rs_encoded_length >= raw_payload_length
+            ):
                 total_bits_needed = (RS_LENGTH_PREFIX_SIZE + rs_encoded_length) * 8
 
                 if len(all_positions) >= total_bits_needed:

src/stegasoo/encode.py

@@ -37,6 +37,7 @@ def encode(
     dct_output_format: str = "png",
     dct_color_mode: str = "color",
     channel_key: str | bool | None = None,
+    progress_file: str | None = None,
 ) -> EncodeResult:
     """
     Encode a message or file into an image.
@@ -118,6 +119,7 @@ def encode(
         embed_mode=embed_mode,
         dct_output_format=dct_output_format,
         dct_color_mode=dct_color_mode,
+        progress_file=progress_file,
     )
 
     # Generate filename

src/stegasoo/steganography.py

@@ -39,6 +39,31 @@ from .debug import debug
 from .exceptions import CapacityError, EmbeddingError
 from .models import EmbedStats, FilePayload
 
+# Progress reporting interval
+PROGRESS_INTERVAL = 1000  # Write every N pixels for LSB
+
+
+def _write_progress(progress_file: str | None, current: int, total: int, phase: str = "embedding"):
+    """Write progress to file for frontend polling."""
+    if progress_file is None:
+        return
+    try:
+        import json
+
+        with open(progress_file, "w") as f:
+            json.dump(
+                {
+                    "current": current,
+                    "total": total,
+                    "percent": round((current / total) * 100, 1) if total > 0 else 0,
+                    "phase": phase,
+                },
+                f,
+            )
+    except Exception:
+        pass  # Don't let progress writing break encoding
+
+
 # Lossless formats that preserve LSB data
 LOSSLESS_FORMATS = {"PNG", "BMP", "TIFF"}
 
@@ -526,6 +551,7 @@ def embed_in_image(
     embed_mode: str = EMBED_MODE_LSB,
     dct_output_format: str = DCT_OUTPUT_PNG,
     dct_color_mode: str = "color",
+    progress_file: str | None = None,
 ) -> tuple[bytes, Union[EmbedStats, "DCTEmbedStats"], str]:
     """
     Embed data into an image using specified mode.
@@ -579,6 +605,7 @@ def embed_in_image(
             pixel_key,
             output_format=dct_output_format,
             color_mode=dct_color_mode,
+            progress_file=progress_file,
         )
 
         # Determine extension based on output format
@@ -594,7 +621,7 @@ def embed_in_image(
         return stego_bytes, dct_stats, ext
 
     # LSB MODE
-    return _embed_lsb(data, image_data, pixel_key, bits_per_channel, output_format)
+    return _embed_lsb(data, image_data, pixel_key, bits_per_channel, output_format, progress_file)
 
 
 def _embed_lsb(
@@ -603,6 +630,7 @@ def _embed_lsb(
     pixel_key: bytes,
     bits_per_channel: int = 1,
     output_format: str | None = None,
+    progress_file: str | None = None,
 ) -> tuple[bytes, EmbedStats, str]:
     """
     Embed data using LSB steganography (internal implementation).
@@ -659,8 +687,9 @@ def _embed_lsb(
 
         bit_idx = 0
         modified_pixels = 0
+        total_pixels_to_process = len(selected_indices)
 
-        for pixel_idx in selected_indices:
+        for progress_idx, pixel_idx in enumerate(selected_indices):
             if bit_idx >= len(binary_data):
                 break
 
@@ -690,6 +719,16 @@ def _embed_lsb(
                 new_pixels[pixel_idx] = (r, g, b)
                 modified_pixels += 1
 
+            # Report progress periodically
+            if progress_file and progress_idx % PROGRESS_INTERVAL == 0:
+                _write_progress(progress_file, progress_idx, total_pixels_to_process, "embedding")
+
+        # Final progress before save
+        if progress_file:
+            _write_progress(
+                progress_file, total_pixels_to_process, total_pixels_to_process, "saving"
+            )
+
         debug.print(f"Modified {modified_pixels} pixels (out of {len(selected_indices)} selected)")
 
         stego_img = Image.new("RGB", img.size)