FAQ

Setup and hardware

Which ESP32-S3 board should I buy? Any ESP32-S3 with USB-C and native USB OTG support. The ESP32-S3-WROOM-1 is the reference board; Supermini variants work well for compact setups. Buy from AliExpress, Mouser, Farnell, Amazon — anywhere. We do not care where you buy it, and we have no way of knowing.

Does Crypt-in work on Mac? Not yet. The beta launches on Windows first, then Linux, then macOS. The .crin format is cross-platform, so files encrypted on Windows will open on a Mac once the client exists.

How long does setup take? About 15 minutes: buy the board, flash the firmware, write down your seed, activate the licence. After that, encrypting a file takes seconds.

Do I need technical knowledge? For the beta, yes — you flash an ESP32-S3 from the command line. The public release will ship a one-click installer.

Seed and recovery

What is the seed and why does it matter? The seed is 24 words that encode your root secret. It works exactly like a cryptocurrency wallet seed: same standard (BIP-39), same mechanism, same responsibility.

Millions of people manage a BIP-39 seed to protect cryptocurrency. The risk is identical, and so is the solution: write it on paper, store it physically, never digitally, never in the cloud. If you can secure a Bitcoin wallet, you can secure Crypt-in.

What happens if I lose my dongle? Buy a new ESP32-S3 (~€5 anywhere), flash the firmware, run the recovery command with your 24 words. The new dongle is cryptographically identical to the old one for file access and all your .crin files open again. One thing does not come back: K_attestation is unique to the physical chip and is never derived from the seed, so the licence server sees a new device — see Recovery.

What if I lose both the dongle and the seed? The data is permanently inaccessible. There is no backdoor and no recovery without the seed. lake8.dev cannot help, because we have never seen it. That is also precisely what stops anyone else from getting in.

Does lake8.dev know my seed? No. It is generated at first boot on your hardware, shown once on serial, and never transmitted. Even if you bought a pre-assembled Kit, the seed did not exist when we shipped it: the factory test ends by erasing NVS, so the keys it generated are destroyed before the dongle is boxed.

Encryption and files

How large can files be? The .crin format sets no hard limit. Performance depends on your hardware. Files above 1 GB are supported but not yet benchmarked in the beta.

Can I encrypt folders? Yes. The Windows client encrypts entire folders, producing one .crin file per file inside.

Can I open .crin files on a different computer? Yes, with the dongle. The format is portable: plug the dongle into any computer running the client and your files open normally.

What happens to my files if my licence expires? They stay decryptable forever, as long as you have the dongle. Only encryption of new files stops at expiry. We never take your data hostage.

Licence and pricing

Why do I pay €30/year if it works offline? The €30/year covers signed firmware updates, security patches, new features, and the licence server for the initial activation. After activation the dongle works offline forever — if we shut down tomorrow, activated dongles keep working.

Can I transfer my licence to a new dongle? Yes, through the recovery procedure: flash a new ESP32-S3 with your seed, then use the licence transfer in the app. Maximum three transfers per year.

What about the beta licence? Beta licences are free and valid for 6 months. If the beta extends, they are all renewed free of charge. You never pay during the beta — see Developer Beta.

Security

Is the ESP32-S3 a secure element? No. It is commodity hardware with documented hardening — secure boot, flash encryption, eFuse, disabled debug pins. It is not FIPS 140-2 certified and it is not a tamper-resistant HSM. For the declared threat model — device theft, unauthorised access, remote exfiltration — it is adequate. For nation-state physical attacks it is not, and we say so in the threat model.

Since July 2026 Secure Boot v2 and Flash Encryption are active on every dongle in use, beta included, verified on real hardware: the eFuses are burned at flashing time, a dongle runs only firmware signed with the lake8.dev key, JTAG is permanently disabled, and a physical flash dump yields ciphertext. There is no beta exception and no unburned dongle in a user’s hands. Anti-rollback is not implemented yet — see NVS storage security.

None of that turns the chip into a secure element. It raises the cost of a physical attack; it does not move it into a different category.

Has Crypt-in been independently audited? Not yet. An independent protocol audit is one of the four gates before public launch, and we will publish the full report when it is done.

Where is the source code? The Windows SDK and the Linux CLI are Apache-2.0; the Personal client is GPL-3.0. The Python files in tools/ are internal test harnesses, not a distributable SDK. All of it will be published in github.com/lake8dev/cryptin-sdk. That repository does not exist yet: it opens at the developer beta on 30 September 2026, through channels dedicated to beta participants, which is why the link is deliberately not clickable here — it would only return a 404. There is no public channel today.

The firmware is the one closed part, and stays closed: with its source anyone could strip the PIN gate and the licence check. Nothing about it is needed to write a client — the HID protocol and the .crin format are published in full, which is the point.

The firmware is closed source and is not published in any repository. It is distributed as a binary signed with the lake8.dev key. With its source, anyone could strip the PIN and the licence check and rebuild the product. The SBOM lists the open-source components it is built from, which is a component inventory for CRA compliance — not a source release.

The specifications are a different matter and are public right now: the HID protocol and the .crin format are documented on this site in enough detail to write an independent client, with no agreement and no repository access.

The Windows client is open source under GPL-3.0; the Windows DLL and the Linux CLI are open source under Apache-2.0, in github.com/lake8dev/cryptin-sdk. The Thunderbird plugin follows at launch. The firmware and the licence server stay closed. The Python files in tools/ are an internal test harness and are not distributed as a product — see Python tools. Full breakdown on the licence page.

Why is the SDK Apache 2.0 and the app GPL v3? The SDK is a transport layer other people embed, including in closed-source products: Apache 2.0 permits that and adds a patent grant that protects integrators. The app runs on your files, so GPL v3 keeps it inspectable. GPL v3 rather than v2 because Apache 2.0 is compatible with v3 and not with v2, and the app links the SDK.