
Prokey Optimum
Our wallet review process
We examine wallets starting at the code level and continue all the way up to the finished app that lives on your device. Provided below is an outline of each of these steps along with security tips for you and general test results.
Released
1st January 2020
Custody
Private keys generated and held by user
As part of our Methodology, we ask: Is the provider ignorant of the keys?
The answer is "yes". Private keys are generated by the user on the wallet.
Read more
Application build
See the last Issue we created.
If you have a binary for a version that doesn't appear on the list, you can drop the file here to register it so somebody can verify its reproducibility:
Passed 11 of 12 tests
We answered the following questions in this order:
We stopped asking questions after we encountered a failed answer.
The answer is "yes".
If the answer was "no", we would mark it as "Fake" and the following would apply:
The answer is "no". We marked it as "Fake".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Fake" and the following would apply:
The bigger wallets often get imitated by scammers that abuse the reputation of the product by imitating its name, logo or both.
Imitating a competitor is a huge red flag and we urge you to not put any money into this product!
The answer is "yes".
If the answer was "no", we would mark it as "Announced but never delivered" and the following would apply:
The answer is "no". We marked it as "Announced but never delivered".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Announced but never delivered" and the following would apply:
Some products are promoted with great fund raising, marketing and ICOs, to disappear from one day to the other a week later or they are one-man side projects that get refined for months or even years to still never materialize in an actual product. Regardless, those are projects we consider “vaporware”.
The answer is "yes".
If the answer was "no", we would mark it as "Un-Released" and the following would apply:
The answer is "no". We marked it as "Un-Released".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Un-Released" and the following would apply:
We focus on products that have the biggest impact if things go wrong and while pre-sales sometimes reach many thousands to buy into promises that never materialize, the damage is limited and there would be little definite to be said about an unreleased product anyway.
If you find a product in this category that was released meanwhile, please contact us to do a proper review!
The answer is "yes".
If the answer was "no", we would mark it as "Not a wallet" and the following would apply:
The answer is "no". We marked it as "Not a wallet".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Not a wallet" and the following would apply:
If it’s called “wallet” but is actually only a portfolio tracker, we don’t look any deeper, assuming it is not meant to control funds. What has no funds, can’t lose your coins. It might still leak your financial history!
If you can buy Bitcoins with this app but only into another wallet, it’s not a wallet itself.
The answer is "yes".
If the answer was "no", we would mark it as "A wallet but not for Bitcoin" and the following would apply:
The answer is "no". We marked it as "A wallet but not for Bitcoin".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "A wallet but not for Bitcoin" and the following would apply:
At this point we only look into wallets that at least also support BTC.
The answer is "yes".
If the answer was "no", we would mark it as "Provided private keys" and the following would apply:
The answer is "no". We marked it as "Provided private keys".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Provided private keys" and the following would apply:
The best hardware wallet cannot guarantee that the provider deleted the keys if the private keys were put onto the device by them in the first place.
There is no way of knowing if the provider took a copy in the process. If they did, all funds controlled by those devices are potentially also under the control of the provider and could be moved out of the client’s control at any time at the provider’s discretion.
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.The answer is "yes".
If the answer was "no", we would mark it as "Leaks Keys" and the following would apply:
The answer is "no". We marked it as "Leaks Keys".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Leaks Keys" and the following would apply:
Some people claim their paper wallet is a hardware wallet. Others use RFID chips with the private keys on them. A very crucial drawback of those systems is that in order to send a transaction, the private key has to be brought onto a different system that doesn’t necessarily share all the desired aspects of a hardware wallet.
Paper wallets need to be printed, exposing the keys to the PC and the printer even before sending funds to it.
Simple RFID based devices can’t sign transactions - they share the keys with whoever asked to use them for whatever they please.
There are even products that are perfectly capable of working in an air-gapped fashion but they still expose the keys to connected devices.
This verdict is reserved for key leakage under normal operation and does not apply to devices where a hack is known to be possible with special hardware.
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.The answer is "yes".
If the answer was "no", we would mark it as "Bad Interface" and the following would apply:
The answer is "no". We marked it as "Bad Interface".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Bad Interface" and the following would apply:
These are devices that might generate secure private key material, outside the reach of the provider but that do not have the means to let the user verify transactions on the device itself. This verdict includes screen-less smart cards or USB-dongles.
The wallet lacks either a screen or buttons or both. In consequence, crucial elements of approving transactions is being delegated to other hardware such as a general purpose PC or phone which defeats the purpose of a hardware wallet. For big exit scams, a companion app could always request two signatures - one for the coffee you are paying and a second to empty your wallet completely. The former could be broadcast while the latter only gets collected for later use.
Another consquence of a missing screen is that the user is faced with the dilemma of either not making a backup or having to pass the backup through an insecure device for display or storage.
The software of the device might be perfect but this device cannot be recommended due to this fundamental flaw.
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.The answer is "yes".
If the answer was "no", we would mark it as "No source for current release found" and the following would apply:
The answer is "no". We marked it as "No source for current release found".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "No source for current release found" and the following would apply:
A wallet that claims to not give the provider the means to steal the users’ funds might actually be lying. In the spirit of “Don’t trust - verify!” you don’t want to take the provider at his word, but trust that people hunting for fame and bug bounties could actually find flaws and back-doors in the wallet so the provider doesn’t dare to put these in.
Back-doors and flaws are frequently found in closed source products but some remain hidden for years. And even in open source security software there might be catastrophic flaws undiscovered for years.
An evil wallet provider would certainly prefer not to publish the code, as hiding it makes audits orders of magnitude harder.
For your security, you thus want the code to be available for review.
If the wallet provider doesn’t share up to date code, our analysis stops there as the wallet could steal your funds at any time, and there is no protection except the provider’s word.
“Up to date” strictly means that any instance of the product being updated without the source code being updated counts as closed source. This puts the burden on the provider to always first release the source code before releasing the product’s update. This paragraph is a clarification to our rules following a little poll.
We are not concerned about the license as long as it allows us to perform our analysis. For a security audit, it is not necessary that the provider allows others to use their code for a competing wallet. You should still prefer actual open source licenses as a competing wallet won’t use the code without giving it careful scrutiny.
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.The answer is "yes".
If the answer was "no", we would mark it as "Failed to build from source provided!" and the following would apply:
The answer is "no". We marked it as "Failed to build from source provided!".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Failed to build from source provided!" and the following would apply:
Published code doesn’t help much if the app fails to compile.
We try to compile the published source code using the published build instructions into a binary. If that fails, we might try to work around issues but if we consistently fail to build the app, we give it this verdict and open an issue in the issue tracker of the provider to hopefully verify their app later.
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.The answer is "yes".
If the answer was "no", we would mark it as "Not reproducible from source provided" and the following would apply:
The answer is "no". We marked it as "Not reproducible from source provided".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Not reproducible from source provided" and the following would apply:
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
- obtain the binary from the provider
- compile the published source code using the published build instructions into a binary
- compare the two binaries
- 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.Application build test result
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.
Tests performed by Matthew Lamb, Daniel Andrei R. Garcia, Leo Wandersleb
Do your own research
In addition to reading our analysis, it is important to do your own checks. Before transferring any bitcoin to your wallet, look up reviews for the wallet you want to use. They should be easy to find. If they aren't, that itself is a reason to be extra careful.