What is a bitcoin wallet?

TL;DR — A bitcoin wallet is software or hardware that stores your private keys and lets you send and receive bitcoin. Wallets range from mobile apps and desktop software to dedicated hardware devices. The most important distinction is between custodial wallets (where someone else holds your keys) and non-custodial wallets (where you hold your own keys). Casa provides a non-custodial multisig vault — meaning you hold the keys, and more than one key is required to authorize a transaction, so losing a single key does not mean losing your bitcoin.

What a bitcoin wallet actually does

Despite the name, a bitcoin wallet does not store bitcoin the way a physical wallet holds cash. Bitcoin exists on the blockchain — a public, decentralised ledger. What a wallet stores is your private key: a unique cryptographic code that proves you own the bitcoin at a given address and allows you to authorize transactions (signing). Without the private key, you cannot send bitcoin from that address. Whoever has the private key controls the bitcoin.

A bitcoin wallet also generates public addresses — the addresses you share with others so they can send bitcoin to you. Think of the public address as your email address (anyone can send to it) and the private key as the password (only you should have it).

Types of bitcoin wallets

Mobile wallets

A mobile wallet is an app on your phone that stores a private key. Mobile wallets are convenient for everyday transactions but are only as secure as your phone. If your phone is lost, stolen, or compromised, the key stored on it may be at risk. Casa Pay is a mobile wallet — a single-key wallet for smaller amounts that is secured by the key stored in your phone's secure enclave and backed up automatically to your iCloud or Google Drive account.

Desktop wallets

A desktop wallet is software installed on your computer. It gives you full control of your key on your own machine but shares the same risk profile as any computer-based application: it can be targeted by malware, and your key is at risk if your computer is compromised.

Hardware wallets (hardware devices)

A hardware device is a dedicated physical device that stores your private key offline. It is designed so that the key never leaves the device, even when you plug it into a computer to sign a transaction. This makes hardware devices significantly more resistant to malware and remote attacks than mobile or desktop wallets. Casa vaults use hardware devices as one or more of the keys in a multisig setup. For help choosing one, see: Which hardware device should I use with Casa?

Custodial wallets (exchanges)

When you buy bitcoin on an exchange and leave it there, the exchange holds the private key — not you. This is a custodial wallet. The exchange can freeze your account, be hacked, go bankrupt, or face regulatory action, and in any of these scenarios you may lose access to your bitcoin. The phrase "not your keys, not your coins" refers to this risk: if someone else holds your private key, you are trusting them with your bitcoin.

Non-custodial wallets (self-custody)

A non-custodial wallet is one where you hold your own private keys. You are in full control of your bitcoin and do not depend on a third party to access it. This is sometimes called self-custody. Casa provides non-custodial wallets: Casa does not hold, control, or have the ability to move your bitcoin.

Single-key wallets vs. multisig vaults

Most bitcoin wallets — mobile, desktop, and hardware — use a single private key. If you lose that key, or if it is stolen, your bitcoin is gone. There is no customer support to call and no way to reverse a transaction on the blockchain. To mitigate this risk, single-key wallets typically generate a seed phrase (a 12- or 24-word backup of the private key) during setup. But the seed phrase itself is also a single point of failure: anyone who finds it can access your bitcoin.

A multisig (multi-signature) vault uses multiple keys. Instead of one key controlling your bitcoin, you need a signing quorum (the minimum number of keys required to send bitcoin) to authorize any transaction. In a Casa 3-key vault, you need 2 of 3 keys. In a 5-key vault, you need 3 of 5. This means that losing a single key, or having it stolen, does not put your bitcoin at risk. You can replace the lost key through a key rotation (replacing one key in the vault with a new one) using the remaining keys.

In a Casa vault, your keys are distributed across different devices and locations: your phone (mobile key), a hardware device (hardware key), and Casa (the Casa Recovery Key, which Casa holds offline on your behalf). The Casa Recovery Key cannot be used alone to move your bitcoin, it is only one key in the multisig setup, and Casa cannot access your vault without the other keys that only you control.

How Casa compares to a traditional bitcoin wallet

	Single-key wallet	Casa multisig vault
Keys required to send	1	2 of 3 (Standard) or 3 of 5 (Premium)
What happens if you lose one key	Bitcoin may be permanently lost	Replace the key using the remaining keys
What happens if one key is stolen	Attacker can move your bitcoin	Attacker still needs more keys to move anything
Custodial?	Depends on the wallet	No — Casa is non-custodial
Support available	Varies	Yes — Casa advisors help with setup, recovery, and security

Ready to get started?

If you are new to self-custody and want to set up your first Casa vault, see: Getting started with the 3-key vault.

If you have questions about which wallet type is right for you, or about how Casa's multisig vault works:

Standard members: email help@team.casa.
Premium and Private Client members: reach out to your dedicated Client Advisor directly.