Trezor

The Trezor is a physical device made by the Czech company SatoshiLabs that keeps a user's private keys isolated from internet-connected computers and phones, exposing them only briefly inside the device itself to sign a transaction before sending the signed result back out. Launched in July 2014 as the Trezor Model One, it is widely credited as the first hardware wallet ever brought to market, predating better-known rivals by roughly a year.

Setup generates a recovery seed phrase of 12 to 24 words following the BIP39 standard, a format Trezor itself helped establish and that most other hardware and software wallets now use. That seed can restore all associated coins on a new device if the original is lost, damaged, or stolen, which is why it should be written down offline and never photographed or typed into a computer. Every outgoing transaction requires physical confirmation on the device's screen or buttons, and an optional passphrase can add a hidden extra wallet on top of the standard seed for further protection.

The current lineup runs from the button-operated Trezor Safe 3 through the touchscreen Safe 5 to the Bluetooth-enabled Safe 7, all of which pair with the Trezor Suite app and support thousands of coins and tokens across many blockchains, including Bitcoin. Unlike some competitors, Trezor's firmware and hardware designs stay fully open source, letting independent researchers audit and verify the security claims.

Because private keys never leave the device, a Trezor gives strong protection against remote hacking and malware, but users remain fully responsible for safeguarding the physical unit and, especially, its recovery seed.