Casa Blog - Bitcoin Security Made Easy

Securing your crypto with a hardware wallet is an important first step in protecting your digital wealth. If your assets represent a significant amount of your net worth, however, it makes sense to upgrade your protection to the industry standard: multiple keys.

Trezor is a great selection to get started with self-custody. In this article, we’ll go over why you should consider incorporating a Trezor device into a multi-key vault with Casa for the ultimate crypto security.

About Trezor

Trezor is one of the leading manufacturers of hardware wallets. Not only were they the first to create a hardware wallet, but they are consistently ranked among the top wallet manufacturers in reviews.

Today, Trezor produces two primary devices: the Model One and the Model T. The Model One is a popular choice that is easy to use and supports bitcoin, ethereum, and other assets. The Model T is a more advanced model with a touchscreen and broader asset support.

The below article provides an overview of how these devices function.

How a bitcoin hardware wallet works
Hardware wallets let you secure your bitcoin away from hackers. Learn the basics of how they operate.

Why should you use multiple keys?

Hardware wallets use one key to secure your funds. Owners of any hardware wallet are always at risk of losing their device, rendering their bitcoin (BTC) or ether (ETH) worthless. Trezor makes owners save a set of 12-24 words — called the seed phrase — that can be used to restore the lost wallet, but these can also be lost or stolen.

Multiple keys add redundancy to your security and help you preserve access to your assets even if one key is compromised.

Use digital vaults to secure your ETH and BTC

One of the inbuilt functionalities of bitcoin is to enable multiple keys to be able to access bitcoin at a particular address. This can also be done with ethereum using smart contracts. At Casa, we refer to these security setups as a vault, also known as a multisig wallet.

With these vaults, more than one private key is required to access the cryptocurrency stored at a particular address. Casa has implemented the following options:

  • 3-key vault: One hardware wallet such as a Trezor, a mobile key, and the Casa Recovery Key
  • 5-key vault: Three hardware wallets, a mobile key, and the Casa Recovery Key

By using multiple keys, these vaults provide you with the redundancy you need and allow you to distribute the personal security risk of holding your own keys. To spend funds, you simply sign a transaction with a majority of keys in your set.

Think of this like a bank vault with multiple keys that must be inserted and turned at the same time to open the vault. This way, if hackers do steal your seed phrase or one of your private keys, they are still powerless to access your BTC or ETH because they would need access to one or more keys, depending on your setup, to open the vault.

How does a Casa vault work with a Trezor?

Our vaults act as an extra layer of protection on top of your existing foundation of cold storage with a Trezor. Using the Casa app with a Trezor device would look like this:

Another private key is stored on the Trezor wallet itself, and you can choose to back up the seed phrase if you wish. You can also use your existing Trezor as long as you know it hasn’t been compromised.

Next, we would generate a mobile key stored on your phone or tablet within the Casa app itself. This key is secured using highly sophisticated cryptography making it very difficult for hackers to access even if they get hold of your phone. If you prefer, you could also opt for a second hardware device.

Last but not least, the Casa Recovery Key will be stored on Casa's secure servers — again, using highly sophisticated cryptographic algorithms and methodologies that make accessing the key supremely difficult should hackers ever breach the system. If one of your other keys is compromised, you can access this key by contacting us and verifying your identity. The greatest benefit of vaults is that, even if cyber criminals do manage to compromise a single key, that key is completely worthless to them because they would need at least two keys to do anything with your BTC or ETH. Learn how to create a 3-key vault with your Trezor here.

Which vault is right for me?

“Secure your bitcoin like it’s an order of magnitude more than the current market valuation.” — Jameson Lopp, Casa co-founder and CTO

If you manage only modest amounts of digital assets, you're probably okay with using only the Casa app on your smartphone, which includes a single key.

If your assets reach a value where you would be upset if anything bad happened to them, you might want to create a 3-key vault using a Trezor One or similar device.

For life-changing amounts, the 5-key vault is recommended, requiring at least three signatures to execute any transactions. In this arrangement, we would use three devices of different types because key diversity makes it harder for bad actors to replicate attacks across devices. This option offers maximum security and peace of mind in the world of ever-increasing cyber threats.

Although no one can guarantee security, the 5-key vault is by far the most secure option on the market for protecting large digital stores of BTC and ETH.

Each of these vaults is easy to set up, and Casa offers a variety of options including personal onboarding and legacy planning for complete asset protection. Get started here.

Get privacy and security updates

Our Security Briefing newsletter provides free updates and analysis on recent developments in bitcoin, digital privacy, and crypto security. Sign up below.

FAQs about Trezor and Casa cryptocurrency vaults

How does a multisig crypto wallet work?

A multisig crypto wallet is a type of crypto wallet that requires more than one signature to authorize transactions from the wallet. These offer the highest level of security available.

What are the benefits of using Casa with a Trezor Wallet?

The Trezor One hardware wallet is a proven hardware wallet with best-in-class security and encryption built into it. Coupled with Casa's multisig solution, these two products offer the highest level of security available for cold storage wallets.

How does integrating Casa with Trezor provide additional layers of protection?

The Trezor One and Trezor Model T are both proven hardware wallets though they require only a single key to carry out transactions. Combining your Trezor device offers the highest possible protection for your cryptocurrency.

How does integrating Casa with Trezor protect from malware and social engineering?

Even if hackers obtain a single key from you by using malware or social engineering, they still can't steal your cryptocurrency because they need multiple keys to access your crypto. Multiple keys make it exponentially harder for hackers to gain access to your funds.