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Security Aspects

In self-custody, the responsibility for the security of digital assets falls entirely on the custodian. Therefore, you need to equip yourself with tools and procedures following the industry's best practices to reinforce every aspect of cybersecurity to achieve the best possible safeguard.


In this section, we emphasize all the security aspects that Cuvex has refined for you, greatly strengthening your roadmap to help you achieve your goals.



The storage strategy you choose depends on the type of operation you conduct. A holder's use case is very different from a trader's. It's also different to store the keys to your Bitcoin wealth compared to storing the keys to your NFTs or other crypto assets. You'll need to craft an ad-hoc strategy, and the market offers numerous options tailored to your needs. However, there is a common factor: the seed phrase. As its name implies, it is the origin of the keys with which you control your crypto assets, so it's where you must focus the most on storage security. ​If you think about it for a moment, the seed is the true key to your crypto assets. With it in your possession, you can move wherever you want. Any wallet, any platform, you will still have sovereign control over what is yours. Both the master private key and the master public key derive from this and therefore depend on it. If you don't protect the seed, anyone who gets hold of it will gain access to your keys and hence your wealth. Therefore, securely storing your seed is a "must-have." And here is where Cuvex offers you something no one else does: the ability to encrypt your seed offline and store it securely. ​The Cuvex device provides a completely offline encryption flow, which, based on the AES256 GCM symmetric cryptography algorithm, converts the seed (or the data you want) into a cryptogram stored on an NFC card. As a result, you have a military-grade data protection system that makes any attack seeking to obtain the secret impractical. The device stores nothing inside, and just by disconnecting the power, any data that might have been processed is lost. The actual storage of the cryptogram is the NFC card, an easy-to-carry storage medium with an estimated lifespan of 10 years. It is also worth noting that the encryption algorithm is implemented at the hardware level. This means that the software does not intervene in this process, thus eliminating more risk vectors.



When it comes to the seed phrase, Cuvex makes it easy for you to strengthen this aspect. Just "clone" as many copies as you deem necessary. The more and better distributed they are, the greater your ability to handle any unforeseen event. In any case, you have to be very disciplined. Here are some aspects to consider: * When encrypting, use a verbose alias to help you identify your cards. * Define separate locations to diversify risk points (theft, floods, fires, etc.). * Perform periodic verification tasks on your backups. This not only helps you monitor their status but also helps you practice the scheme you've implemented. * Do not mix secrets; use different cards for each one. These good practices should also be replicated on any other device you have included in your security setup (hardware wallet, hardware signer, etc.). Depending on the manufacturer of each device, you should evaluate the redundancy options it offers. If it doesn't offer anything in this regard, you can always use Cuvex to store those secrets (wallet keys, passphrases, exchange keys, etc.).

Physical Integrity

As you might imagine, you don't need a vault or safe for your Cuvex card. A thief will find your cryptogram useless without the password to access it. And this, my friend, is only in your mind. You’re light years ahead of banks and have done it with just a few bucks. However, you should consider protecting your cards from electromagnetic interference, current induction, or electrical disturbances. You can achieve this using a Faraday cage. There are plenty of options on the market, although we recommend ours. Check out the options available in our store. Regarding the Cuvex device, physical connection to the electronic circuits is factory-restricted. That means physical access to the microcontrollers for debugging or modification is not possible. Once the software component called "Bootloader" is installed in our factory, we cannot modify anything on the circuit, not even access these components. If something goes wrong, we can only discard the device's electronics as it becomes irrecoverable.

Software Update

This is a measure that must be executed rigorously; it is essential to always keep all software within your implemented scheme updated. This helps prevent and protect against known vulnerabilities exploited by hackers. Regarding Cuvex, the update process is designed to ensure proper software maintenance at all times without compromising encryption operations or the isolation of the secure element. The only communication channel chosen for the update is the Bluetooth protocol, using a one-way temporary link implementation. The mobile application acts as an air gap to the internet to download the Firmware and then synchronously sends it to the Cuvex device via BLE. Each time a new update is available, you will receive a Push notification on your mobile so that, when you decide, you can proceed to download and then install it on the device. It is worth noting that the Bluetooth technology is isolated in a memory partition governed by the Bootloader, whose function is to manage and preserve the integrity of the device's Firmware. Therefore, it is impossible to use that channel from the Firmware itself, which implements all functional processes (encryption, decryption, card writing, etc.). In other words, even if an attacker managed to connect via Bluetooth, they would not be able to modify or capture any functional process, as the channel only communicates with the Bootloader partition, which only allows Firmware updates.


Theft and Threats

Many people don't take this aspect of security seriously, dismissing the possibility that it could happen to them. Some even flaunt it: posting relevant information about their crypto assets on social media, putting their Hardware Wallet sticker on their car window, etc. The truth is, robbing a self-custodian can be very lucrative, and the statistics are growing exponentially. It's wise to be physically and mentally prepared for this eventuality, including measures in your designed scheme. When it comes to hardware wallets, more and more offer the ability to manage “secondary wallets,” allowing you to keep the real one hidden and a superficial one to mislead the attacker. Additionally, if you create a passphrase when defining your seed, you add an extra layer of security that will allow you to control a threat situation where you are forced to hand over the keys. As an additional measure, Cuvex offers multi-signature when creating your cryptogram. This greatly strengthens your scheme by allowing you to diversify the ownership of the key to your secret. Even if the thief threatens you with a wrench, they will have to settle for the fact that you are only a fragment of the key that opens the chest. If your implementation also involves cyberspace, you need to be even more careful. The main avenue of theft and threats is here, and any measure you take is not too much. The best practice is to designate a computer exclusively for this purpose, not use any unknown software, and always connect via VPN, preferably through TOR. It's worth reminding you that regarding Cuvex, none of the device's processes require an internet connection. Even the firmware update is done without an internet connection; the app is responsible for downloading the update and then sending it through a secure one-way Bluetooth channel.

Impersonation and Scams

Continuing from the measures outlined in the previous point, be aware of the potential scams you could fall victim to. Cyberspace is full of traps seeking to steal your wealth. Pay special attention to the details from the sites you visit, check sources, look for proof of authenticity, investigate, and above all, do not provide any personal information or anything related to your crypto assets. On the physical side, the devices you choose should have mechanisms that allow you to verify their integrity and authenticity, and of course, always buy directly from the manufacturer. Regarding Cuvex, both the packaging and the device are sealed with a security label that lets you see at a glance if it has been tampered with. Additionally, you can validate the shipping traceability using the service offered by the Cuvex App, where by entering the label codes, you confirm the authenticity of what you have received. Regarding the communications between the device and the App for the software update process, pairing requires OTP validation and certificate exchange. This prevents third parties from using this connection and ensures the authorship of the update. Lastly, at the software level, it is worth noting that the Cuvex device only allows the installation of original firmware signed by Cuvex. The bootloader does this through asymmetric authentication of the RSA signature of the software to be installed (Firmware). Thus, even if any described process fails, the device will authenticate the firmware to be installed and eliminate any attempt to install spoofed software.

Counterparty Risk

What happens if we disappear tomorrow and your Cuvex breaks? Nothing, because you have all the source code published and can set up your own implementation of the solution. Of course, this implies a technical task you will have to face, but the good news is that it is entirely in your hands; you remain completely independent. We are just facilitators of this technique that makes your mission more comfortable, but if one day we are gone (God forbid), your self-custody scheme will prevail. Verifiable, visible and editable source code. Cuvex code can be compiled by yourself. You should look for this virtue in any other device you include in your scheme. Also, choose the technologies you use carefully; there are solutions that disguise themselves as self-custody support, but if this involves sharing part of the key to the treasure... well, you know. The list of false prophets in the crypto industry continues to grow and will keep doing so until it matures. Avoid those counterparty risks; do not place your security solely on the trust of words that are not yours.


Although we have addressed this aspect in previous points, it deserves special mention due to the high risk of neglecting it. Our recommendation is to always maintain a low profile. Threats from third parties often arise from information that victims themselves imprudently share on social media and other platforms. The best way to strengthen this aspect of security is by staying under the radar of criminals. Do not share information about your cryptocurrency holdings online, and if you are forced to undergo KYC, think twice. Choose the companies where you provide your data wisely, as each one poses a potential vulnerability in your self-custody scheme. This applies not only to exchanges and device manufacturers but also to governments that may request sensitive information about your crypto assets. More than one administration has shown poor cybersecurity practices.

Disaster Plan

If, for any reason, your twin towers come crashing down, you must have the ability to move forward. Nothing is infallible, so you need to have a plan for catastrophic events. Whether it's because governments are going after the manufacturer you chose or a natural disaster wipes everything out, you need to plan what to do in that situation to avoid being caught off guard. This aspect should be reinforced with the points covered earlier, but you need to spend specific time thinking about how to handle the failure of any element of your solution. Here, pen and paper will be your best allies. Thoroughly investigate the virtues offered by each chosen provider and eliminate the risk vectors you identify. Ask the necessary questions to the relevant parties and rely on your trusted circle to take advantage of aspects like redundancy and multi-signature.

Continuous Learning

Finally, although it may seem repetitive, continuous study of your scheme is mandatory. Technology advances at a rapid pace, and you can't rest on your laurels. What is a strength today can become a weakness tomorrow. You must stay up to date at all times; there is no other option. And of course, you should demand the same from every company you decide to include in your scheme. A provider that shows no signs of life is a red flag on your dashboard. If you notice that the technology you use is being abandoned or is not heading in the desired direction, don't be the last to jump ship. And don't forget the community, one of the greatest virtues of this industry. Just like Cuvex, any other technology you include should be open to the community. This allows you to verify that they do what they claim to do and to enrich and strengthen the virtues of that technology. Open-source code is undoubtedly a strong asset for cybersecurity.

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