CrossBar does not give you twenty-four words at setup. Your private key is generated as three separate shares, one on your phone, one inside your CrossBar hardware device, and one encrypted for recovery. Two of them sign each transaction. The complete key is never assembled anywhere, at any point, including inside our own hardware and on our servers.
There is no seed phrase because there is no single secret for a phrase to represent.
Why other wallets need one
Nearly every wallet derives everything from one master secret. All your addresses, across every chain, unfold from one number, and the twenty-four words are that number written so a human can copy it.
That gives you one point of failure to defend for life. The backup is dangerous because the backup is the wallet. Anyone who reads the paper owns the funds. And the randomness that picked those words is a single point of failure too: in July 2026, Coldcard shipped devices whose hardware random number generator was never actually called by the firmware. Nothing was hacked. The seeds were simply predictable, and every wallet derived from one stayed predictable forever, on any device it was restored to.
How the three shares work
The key is split before it exists as a whole. The shares are generated independently and mathematically related, so there is no moment during setup when a full key sits in memory waiting to be divided.
In normal use, your phone and your CrossBar device sign together, offline. The third share is encrypted and exists only for recovery. A share alone is not a partial key that exposes part of your funds. It is useless by itself, which is why splitting a key is not the same as sharing it. No one else holds yours, CrossBar included.
Why the secure hardware belongs in your hand
CrossBar is not the first wallet to split keys. The difference is where the hardware sits. Most multiparty computation wallets keep their shares in the provider's cloud, so your security rests on Apple's enclave and a company's uptime, and every signature waits on a third party.
Our Personal Hardware Security Module is built on CrossBar's Secure Processing Unit, which pairs the protections of a secure element with the processing power of a microcontroller. That headroom is what makes on-device multiparty computation possible at all. Signing needs no cloud connection, the output is an ordinary signature so the wallet works across chains, and replacing a device reshares your keys without changing your address.
Underneath, keys are stored in ReRAM rather than flash. Each cell is a physical switch instead of a trapped electrical charge, so there is nothing to leak. The silicon is RISC-V with a fully open specification, which matters for the reason Coldcard demonstrated: you can read every line of a wallet's open source code and still be trusting a proprietary chip one layer down.
What it means in practice
Setup is your phone, your device, and a few minutes, with nothing to write down and nothing to install on a computer. If your phone is lost or replaced, the shares move to the new one and your address stays the same. The event that permanently ends access to funds with a seed phrase wallet becomes an ordinary afternoon.
— The CrossBar Team