BitSplit Media Delivery

BitSplit changes how WordPress delivers public media. Instead of keeping a
complete file at a stable public URL, it stores the original and generated sizes
as incomplete blocks and reconstructs each file in the visitor’s browser through
a short-lived session.

It is a media-protection layer for photography portfolios, publishers, member
sites, and other WordPress sites where making direct downloads and bulk collection
harder is valuable.

Why use BitSplit?

• No stable ready-to-download media URL – public paths serve incomplete
  blocks rather than finished files.
• Images, video, and audio – every supported media type is handled by the
  same delivery flow.
• Normal WordPress workflow – use the Media Library, Gutenberg Image, Gallery,
  Video and Audio blocks, featured images, and responsive srcset markup as usual.
• Two access modes – keep media public while adding download friction, or
  require visitors to sign in before reconstruction.
• No external service – reconstruction runs on your WordPress site and in the
  visitor’s browser, with no SaaS account, license key, quota, or payment.
• Backup and recovery tools – export a recovery manifest before site changes
  and restore attachment mappings when needed.

BitSplit is not encryption, DRM, or a promise that downloading is impossible.
A determined viewer can inspect the browser flow, automate reconstruction, or
capture rendered content. Use it when raising the cost of casual downloading is
valuable; use established encryption and access control when confidentiality is
required.

Included functionality

The plugin protects any number of image, video, and audio attachments.
Every feature is free: there is no paid tier, license key, trial, add-on, or
usage quota, and the plugin contacts no external service.

It includes public or logged-in-only access, Gutenberg image, gallery, video and
audio support, featured-image and srcset handling, and backup/recovery tools.

Delivery flow

1. WordPress stores each file as an incomplete BitSplit block, with reconstruction
   data stored separately in attachment metadata.
2. Front-end markup receives a placeholder instead of the original media URL.
3. The browser establishes an ephemeral P-256 ECDH session.
4. Reconstruction data is transported with HKDF and AES-256-GCM.
5. Block bytes require a short-lived, session-bound signed token.
6. The browser reconstructs the file into a temporary Blob URL. Video and audio
   are streamed through a Service Worker so playback can seek.

The transport encryption protects reconstruction data in transit; the BitSplit
block itself is not encrypted and contains most source bytes.

Access modes

• Public visitors – public media remains viewable; BitSplit adds download and
  scraping friction.
• Logged-in users only – anonymous visitors cannot obtain reconstruction data
  or block bytes.

WordPress coverage

BitSplit handles normal attachment images, Gutenberg Image, Gallery, Video and
Audio blocks, featured images, srcset, classic content containing wp-image-ID,
and the [bitsplit id="123"] shortcode.

Storage

Incomplete blocks are stored in a plugin-owned directory resolved through
wp_upload_dir(), while reconstruction data stays in WordPress post metadata.
The plugin does not write web-server configuration files or require users to edit
server configuration.

Requirements

• PHP 7.4 or newer
• GMP extension
• OpenSSL with ECDH support