Zip Bundles

The Zip Bundle feature lets you package multiple files into a single encrypted archive and send them as one queue item. You can optionally add an AES-256 zip-level password for an additional layer of protection on top of the transport encryption.

Creating a zip bundle

In the sender UI

  1. Open the sender web UI (http://localhost:5000)
  2. Click the Zip Bundle tab

📸 Screenshot needed: zip-bundles-sender-tab.png Description: Sender web UI with the Zip Bundle tab selected, showing the multi-file drop zone and password field

  1. Add files using any of these methods:
    • Drag and drop multiple files onto the drop zone
    • Click Add Files to open a multi-file picker
    • Repeat to add more files one by one

📸 Screenshot needed: zip-bundles-sender-files-added.png Description: Zip Bundle tab showing several files listed with names, sizes, and a remove button for each

  1. (Optional) Enter a zip password in the password field

    • The password is used to encrypt the zip archive contents using AES-256 at the zip level
    • Leave blank for a standard (unpassworded) zip bundle

  2. Click Create & Queue

The sender will:

  • Bundle all selected files into a zip archive using SharpZipLib
  • If a password was provided, encrypt the zip entries with AES-256 at the zip level
  • Hash the resulting zip bytes with SHA-512
  • Encrypt the entire bundle with AES-256-GCM (transport encryption)
  • Add it to the queue

📸 Screenshot needed: zip-bundles-sender-queued.png Description: Sender queue showing the zip bundle item with a lock icon (if passworded) and Queued badge

Double encryption explained

When you use a zip password, your files are protected by two independent layers of AES-256 encryption:

flowchart TD
    A[Original files] --> B["AES-256 zip encryption\n← zip password you enter"]
    B --> C[.zip archive]
    C --> D["AES-256-GCM transport encryption\n← key derived from session secret"]
    D --> E[Encrypted bytes in queue]
    E --> F[Sent over HTTPS Dev Tunnel]

    style B fill:#2d4a3e,color:#fff,stroke:#2ea043
    style D fill:#1a3a5c,color:#fff,stroke:#4a9eff
LayerAlgorithmKey source
Zip-levelAES-256 (zip entry encryption via SharpZipLib)Password you enter
TransportAES-256-GCMSHA-256 of session secret

This means that even if the transport encryption were somehow broken, the zip contents would still be protected by the zip password — and vice versa.

Lock icon in the queue

Zip items with a password show a 🔒 lock icon in both the sender and receiver queues, making it clear that the recipient will need the zip password to extract the files.

⚠️ Warning: The zip password is not transmitted with the bundle. You must share it with the recipient separately through a secure channel.

Receiving a zip bundle

In the receiver UI

📸 Screenshot needed: zip-bundles-receiver-queue.png Description: Receiver queue showing a zip bundle item with lock icon and Receive button

  1. Click Receive next to the zip item
  2. The receiver downloads and decrypts the transport layer (AES-256-GCM)
  3. SHA-512 hash verification runs on the decrypted zip bytes
  4. The hash verification modal appears

📸 Screenshot needed: zip-bundles-receiver-hash-modal.png Description: Hash verification modal for a zip bundle showing success

  1. If verification passes, a Download button appears
  2. Click Download — the .zip file is saved to your machine

Extracting the zip

If the bundle was created with a password:

Windows (File Explorer)

Right-click the .zip → Extract All → enter password when prompted.

macOS (Terminal) 

  unzip -P "your-zip-password" bundle.zip

Linux (Terminal) 

  unzip -P "your-zip-password" bundle.zip
# or
7z x bundle.zip -p"your-zip-password"

⚠️ Warning: If you forget the zip password, the files cannot be recovered. The password is not stored anywhere in the system. You will need the sender to re-create and re-send the bundle.

File size limit

LimitValue
Maximum zip bundle size (total)100 MB

The 100 MB limit applies to the final zip archive size, not the sum of individual file sizes (compression may reduce the total).

Use cases

  • Sending a project folder (multiple source files at once)
  • Bundling certificates, keys, and config files together
  • Packaging assets that belong together logically
  • Sending files that benefit from an extra layer of password protection