Preview Video 🔒

The video sibling of PreviewImageCryptIO: it does what the stock preview node does - write the result to ComfyUI's temp directory so you can watch it in the UI - except the file that lands on disk is encrypted, and your browser decrypts it on the way back for playback.

It's one node in the CryptIO pack, which encrypts data moving between browser and server using RSA. The server auto-generates a keypair when it starts, your browser auto-fetches the public key, and none of that needs manual setup on your end. This node applies that encryption to a generated video clip before it hits the temp folder.

The inputs

Two fields, both required:

• video (VIDEO) - the clip you want to preview, from wherever upstream in your graph produced it.
• auto_download (BOOLEAN, default false) - turn this on and the node automatically kicks off a browser download of the decrypted clip once it's ready, saving you a manual save-as from the preview player.

There's no format or quality control here the way the image version has - video encoding is handled without exposing those knobs at this node. And like the image preview, there's no output; is_output_node is true, so this ends its branch of the graph.

Why bother encrypting a preview clip

The motivation is the same as everywhere else in CryptIO: ComfyUI, run on a shared or remote machine, generally serves temp and output files over an endpoint with no authentication by default - a gap the community flags often enough that "secure your ComfyUI instance" PSAs are a recurring genre. A video sitting unencrypted in the temp directory is readable by anyone who can reach that path directly, independent of your own browser session. Encrypting it means a direct hit on that file gets ciphertext; your browser, which already fetched the server's public key and knows how to work with this pack, still plays it back fine. It's a specific, narrow protection - the network path and file-at-rest, not the endpoint's lack of auth itself - but it's a real gap it closes.

Installing it

Same repo, same steps as every CryptIO node: through ComfyUI Manager, search "ComfyUI-CryptIO," install, restart. Manually: cd ComfyUI/custom_nodes && git clone https://github.com/Suzu008/ComfyUI-CryptIO, restart ComfyUI. No model files involved anywhere in this pack, so there's nothing multi-gigabyte to wait on - it's Python plus frontend JS.

Troubleshooting

Video is heavier than the pack's other data types, so expect the encrypt-then-decrypt round trip to take noticeably longer than it does for a still image, especially on longer clips - that's overhead, not a hang, though give it a reasonable amount of time before assuming something's wrong. If auto_download is on and you're iterating on a workflow that generates several previews in a row, you'll get a download prompt every time, which gets tedious fast - turn it off while you're still tweaking and switch it on only for the take you actually want to keep.

As with the rest of this pack: it's a small, recently-scaffolded project (the README still shows the unedited cookiecutter template boilerplate), so there's no substantial community troubleshooting history beyond the README and the node's own tooltips. If playback never appears, a hard refresh of the browser tab is worth trying first - stale cached frontend JS after a pack update is a common enough cause of custom-node UI glitches across ComfyUI generally.