Frequently asked questions
The basics
What is HILIA?
HILIA (Hide Like A Pro) is a pair of image-privacy tools from TYO Lab: a steganography tool that hides any file inside an ordinary-looking image and reveals it later, and a watermarking tool that embeds invisible, key-locked IDs in images — plus a client-side visible watermark. It runs in your browser at hilia.tyo.com.au/app.
Is HILIA free?
Mostly. Hiding, revealing, probing, capacity checks, watermark extraction and detection are all free with a free TYO ID account. Only two operations spend gas: covert watermark Embed and Stamp (1 gas per image, or unlimited with a membership). The visible watermark is free and runs entirely in your browser.
Do I need an account?
Yes — every operation that touches the HILIA service requires a signed-in TYO ID, which is free to create. The one exception is the visible watermark, which runs client-side and works without signing in.
Is hiding files in images legal?
Steganography is a legitimate privacy technique — the same mathematics that powers digital watermarking, which is used commercially everywhere. Like encryption, what you do with it is subject to your local laws. HILIA is built for lawful use: protecting sensitive attachments, watermarking creative work, and private communication.
Steghide
Can someone tell my image has a file hidden in it?
Not by looking. Statistical analysis can sometimes flag stego images, especially with large payloads. If that's in your threat model, use a "harder to detect" hiding method, keep the payload small relative to the carrier, and set a passcode so that even a flagged image yields nothing.
Will my hidden file survive WhatsApp / Instagram / email?
Inline photo sharing on most platforms re-compresses images, which destroys hidden data. Sending the image as a file or document attachment preserves it — as do email attachments and cloud-drive links. When unsure, zip the image first or probe the received copy.
What happens if I forget my passcode?
The payload is unrecoverable — HILIA doesn't store passcodes and there is no reset. Keep passcodes in a password manager.
How big a file can I hide?
It depends on the carrier and method — a 12-megapixel PNG with the roomiest method holds several megabytes. The Capacity panel gives exact numbers for your image.
Watermark
What's the difference between the covert watermark and steghide?
Steghide maximises payload (whole files) and needs the image to travel untouched. The covert watermark carries only a short ID but is built to survive recompression and moderate edits. Use steghide to move data, the watermark to prove ownership.
Will the covert watermark survive editing?
It survives what images normally go through online — recompression, format conversion, moderate resizing. Heavy crops, aggressive filters or tiny thumbnails can degrade it. Embed at higher strength when you expect rough treatment, and test your own pipeline with Detect.
Can I use the watermark from my own code?
Yes — the developer API exposes embed, extract and detect over HTTPS with API keys and monthly quotas. See the Developer API doc.
Android app
Does the HILIA Android app have a decoy vault?
Yes. The Android app's decoy vault is a second vault with its own passcode — it looks and behaves exactly like your real vault, but only shows what you've chosen to put in it. It's meant for moments you can't simply say no to unlocking your phone: a border check, a workplace policy, or someone else asking you to. See the Android app overview for how it works.
What happens if someone forces me to unlock my phone?
Unlock with your decoy passcode instead of your real one — the decoy vault opens to whatever you've put in it, while your real vault stays closed behind a different passcode. Treat it as one extra layer, not a guarantee: put something believable in the decoy vault, and never reuse a passcode between the two.
Can I stop a hidden photo from sitting in an obvious "Hilia" album?
Yes — turn on Scatter in the Hide flow on the Android app. Instead of staying in Hilia's own Vault, the finished photo saves into your regular phone gallery, mixed in with everything else you've taken. It's more private, but you'll need to remember which photo holds your secret yourself, since it's no longer grouped for you.
Is the Android app free?
Yes — hiding, revealing and the vault (including the decoy vault) are free for everyone, with no account required, supported by ads. An optional Gold membership removes the ads and adds a few extras; it doesn't unlock anything you'd otherwise have to pay to use.
Does the leaderboard show what I've hidden?
No. The optional XP leaderboard tracks how often you use the app and ranks you against other users — it never sees, scores, or reveals anything inside your vault. It's opt-in, and skipping it doesn't change how hide, reveal or the vault work.
Account
What is gas?
Gas is HILIA's usage credit: 1 gas per successful watermark Embed or Stamp. Top up from the tool's header, or take a membership for unlimited watermarking. Failed operations never spend gas, and everything else is free.
Does HILIA keep my images?
No — images and payloads are processed in memory to perform the operation and are not retained. Usage metering records that an operation happened, not its content. See the privacy policy for details.