Open format and independent decrypt tool

Every app that encrypts your data asks for trust. Silo tries to need less of it. Instead of “trust us, it’s encrypted”, it publishes how the vault is built and gives you a way to open it without us.

What it does

Two things are public:

• The format. A complete description of how Silo stores a vault: the containers each photo, video and file sits in, the key file that your PIN and recovery phrase open, the encrypted index of names and albums, and the ciphers used. It is on the format page.
• The decrypt tool. silo-decrypt is a small free program that reads a copy of a vault folder plus your recovery phrase and writes your original files to an ordinary folder. It is on the decrypt tool page.

How it works, step by step

1. Copy your vault folder from your phone, or from a copy you made, to a computer you trust.
2. Download the tool and install the one package it needs.
3. Run it with the vault folder and an empty output folder.
4. Type your recovery phrase. It is never a command-line argument, so it does not land in your shell history, and what you type is hidden.
5. Get your files. They come back sorted into albums, with their names and dates, and a manifest lists everything that was read and anything that could not be.

The full commands are on the decrypt tool page.

Why it matters

Three reasons.

You are never locked in. If the app is gone, the company is gone or you just want out, a vault copy and your phrase are enough. Your photos don’t live or die with us.

You can check our claims. The format says which cipher, which key method and which sizes. Anyone with the skill can confirm that what Silo says matches what Silo does. The tool was written from the document alone, and its tests compare its output byte for byte with the files the app imported.

It makes the encryption honest. A format that is public has to survive being read by experts. Silo’s strength comes from the keys, not from keeping the design secret.