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Prokey Optimum

🔍 Last analysed 15th March 2022 . Not reproducible from source provided
1st January 2020

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Help spread awareness for build reproducibility

Please help us spread the word, asking Prokey Optimum to support reproducible builds  via their Twitter!

Do your own research!

Try out searching for "lost bitcoins", "stole my money" or "scammers" together with the wallet's name, even if you think the wallet is generally trustworthy. For all the bigger wallets you will find accusations. Make sure you understand why they were made and if you are comfortable with the provider's reaction.

If you find something we should include, you can create an issue or edit this analysis yourself and create a merge request for your changes.

The Analysis 

The product page’s description reads as below:

The Prokey Optimum is a secure, easy-to-use cryptocurrency hardware wallet that protects your crypto assets from online and offline attacks, while also supporting a wide range of cryptocurrencies without installing any application, letting you enjoy an all-in-one web-based wallet.

Interface

This hardware wallet features a screen display and 4 buttons to navigate the interface. You can connect this device using a USB cable.

Private keys can be created offline - ❓

To set up the Prokey Device, it must first be connected to a laptop/computer. The user must go to the web interface and install the firmware to start running the wallet. Once this is installed, you can create a wallet.

From the guide, “Restore your wallet from backup”

Your private key is your own and due to security reasons, the whole process of restoring private keys should only be done on the device and offline.

Private keys are not shared - ✔️

An official blog post concerning this product’s release has some information on how private keys are kept secure.

The only possible way for someone to “hack” into the physical device that you have is to physically take it from you but often, you will not lose access to your funds and keys. This is because whoever took your device will still need access to your recovery seed and passphrase; both you would have stored offline and not on a server or on a hard drive.

The Prokey Optimum does exactly this. It stores the keys that grant you access to your funds physically in a protected area of a microcontroller. This eliminates the ability to transfer the keys out of the device in plaintext. The keys will never be exposed to anything that can compromise software, inclusive of hacking, malwares, and malfunctions.

Device displays receive address for confirmation - ✔️

The Help Center’s guide on sending and receiving states that the user can confirm the receive address via the Prokey device’s display.

Confirm the Transaction on Your Prokey

Right after pressing Send, a confirmation popup will appear. Check again the amounts and the recipient address of the transaction. If all is in order, choose confirm. If something is off with the amount or the address shown, there is a possibility that your computer is infected. Rest assured, your coins are still safe in your Prokey, though we strongly advice you to contact support.

The total amount of the transaction, including the fee will be displayed on your Prokey after you confirm the address and amount of coin to be sent. Check them again one last time before holding down the OK key to sign and send the transaction.

Code and Reproducibility

In the official GitHub account, we find a repository named “prokey-optimum-firmware.” The repository has had a recent release on October 4.

Sadly the device has a fundamental flaw when it comes to verifiability: It does not show which binary the user is about to update, at least judging by this video. Without that, the firmware is not verifiable.

(ml, dg, lw)

Verdict Explained

We could not verify that the provided code matches the binary!

As part of our Methodology, we ask:

Is the published binary matching the published source code? If not, we tag it Unreproducible!

Published code doesn’t help much if it is not what the published binary was built from. That is why we try to reproduce the binary. We

  1. obtain the binary from the provider
  2. compile the published source code using the published build instructions into a binary
  3. compare the two binaries
  4. we might spend some time working around issues that are easy to work around

If this fails, we might search if other revisions match or if we can deduct the source of the mismatch but generally consider it on the provider to provide the correct source code and build instructions to reproduce the build, so we usually open a ticket in their code repository.

In any case, the result is a discrepancy between the binary we can create and the binary we can find for download and any discrepancy might leak your backup to the server on purpose or by accident.

As we cannot verify that the source provided is the source the binary was compiled from, this category is only slightly better than closed source but for now we have hope projects come around and fix verifiability issues.

The product cannot be independently verified. If the provider puts your funds at risk on purpose or by accident, you will probably not know about the issue before people start losing money. If the provider is more criminally inclined he might have collected all the backups of all the wallets, ready to be emptied at the press of a button. The product might have a formidable track record but out of distress or change in management turns out to be evil from some point on, with nobody outside ever knowing before it is too late.