need a dedicated app for data redaction on mobile, or just use Signal

the Signal messenger can be used to redact metadata, without having to send a photo to a contact

aCropalypse drew my attention to reassessing data redaction.

privacyguides.org publishes a list of tools, some of which are very powerful. For many folks, all they'll want is to redact metadata like location before sending photos.

Instead of installing one of the mobile apps in the list above, just use the iOS Share Sheet to share the image with Signal messenger. Signal removes metadata of images shared using the app (source code of this functionality).

You don't have to share the image with other people. You can share the image to the built-in Note to Self, which displays like any other recipient. On sharing, the metadata will be redacted. From Note to Self, you can share the image onwards, again using iOS Share Sheet to other people or one of your own apps.

For simple use cases, there is no need to install another app and increase attack surface area.

meta

sources

  1. https://arstechnica.com/gadgets/2023/03/google-pixel-bug-lets-you-uncrop-the-last-four-years-of-screenshots/
  2. https://signal.org/
  3. https://github.com/signalapp/Signal-Android/blob/4ea886d05afbf1ca250cfd2b7a6835748828d6ba/app/src/main/java/org/thoughtcrime/securesms/jobs/AttachmentCompressionJob.java#L137