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How do you move files into the vault safely?

Published By Stillgarth3 min read

To move a file into the vault safely, use Add, then Move files into vault. Stillgarth encrypts each file into the vault, checks that the vault copy opens to exactly the same bytes, and only then erases the original. If you’d rather keep the original where it is, use Import files instead.

What’s the difference between Import and Move?

The vault’s Add button offers four choices:

  • Import files: encrypted as they’re added. The originals stay where they are.
  • Move files into vault: encrypted, then the originals are erased.
  • Take photo: goes straight into the vault, not to your gallery.
  • Create folder: keeps files sorted inside the vault.

Both Import and Move use Android’s own file picker, so Stillgarth only ever gets the files you pick. For Move, the picker also gives Stillgarth the right to delete the files you picked, which is how it can remove the originals afterwards.

What does Move actually do?

For each file you pick, in order:

  1. The file is encrypted with AES-256-GCM on the phone and stored in the vault.
  2. The vault copy is decrypted again and compared with the original (a SHA-256 check).
  3. Only if they match is the original erased.

How the original is erased depends on where it was. A file stored on the phone itself (phone storage, Downloads, the gallery) is overwritten with zeros and then deleted. A file that lives in another app, such as Google Drive, can only be deleted through that app, and that app may keep it in its trash.

When it’s done, a summary tells you what happened to each file:

  • If the vault copy didn’t check out, it is removed and the original is left alone.
  • If the original changed while it was being moved, or couldn’t be read again, it is kept.
  • If the app it came from doesn’t let Stillgarth delete it, the original stays, and the summary names it so you can delete it yourself.

What can erasing the original not promise?

Before it starts, Stillgarth says this plainly, and it’s worth knowing why:

  • Copies somewhere else aren’t touched. If your gallery is backed up to Google Photos or a cloud drive, or you sent the file to someone, those copies still exist. Stillgarth can only erase the one file you picked.
  • Phone storage can keep traces. Flash storage moves data around internally, so even a file that was overwritten and deleted can leave traces on the chip. Overwriting makes recovery much harder; it can’t make it impossible.
  • Trash folders. Some apps keep deleted files in a trash or “recently deleted” folder for a while. Empty it if you want the file gone from that app too.

So for something truly sensitive, the safest habit is to capture it in the vault directly. Take photo saves the picture straight into the vault, and it never touches your gallery.

Is there a size limit?

Yes. A file bigger than about a fifth of the memory Android gives the app can’t be added, exported or shared (roughly 100 MB on a phone that gives the app 512 MB). Stillgarth refuses it with a message rather than failing halfway. Previews inside the vault stop at 64 MB; bigger files can still be exported or shared to open elsewhere.

The limit exists because the whole file is decrypted and its integrity checked before a single byte is shown, so the file has to fit in memory. Photos and documents fit easily.

What happens to files once they’re inside?

Each file is stored as an encrypted blob with a random name. Its real name, type, folder and date are kept in an encrypted database, so what sits on the phone is a folder of anonymous, scrambled files. Photos, PDFs and text open inside the vault without ever being written to the phone in readable form, and you can swipe between photos one at a time.

Other kinds of file can be exported or shared when you need them. Keep in mind that an exported copy is readable wherever you send it, so it’s no longer protected by the vault.

How do you keep them safe after that?

Inside the vault, your files are protected by your vault password, PIN or fingerprint, and the vault locks itself when you leave it, when the screen turns off, or after the delay you choose. Two more habits help: