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Hardware wallet is a physical device designed to hold private keys and sign cryptocurrency transactions separately from an internet-connected computer or phone. In a typical Bitcoin wallet arrangement, companion software prepares a transaction, the hardware wallet signs it, and the companion software broadcasts it. This separation can reduce exposure to malware on the connected device, but does not make a wallet immune to theft or compromise.[1]
Operation
The networked wallet and signing device perform different tasks. Companion software can monitor balances and construct unsigned transactions without holding the spending keys. The signing device reviews and signs transaction data, then returns the result for broadcast. Bitcoin’s Partially Signed Bitcoin Transaction (PSBT) format provides a standard way to exchange transaction information between software and signing devices.[2]
An on-device display allows users to check transaction details independently of the host computer. Its usefulness depends on the device’s integrity and on which details its software can decode and display. For smart-contract interactions, blind signing means approving data whose meaning cannot be adequately checked on the device. Human-readable transaction decoding can improve review, but support depends on the device, application and contract; a valid signature can still authorize an unwanted transfer.[3]
Backup and recovery
Many deterministic wallets derive keys from a seed backed up as a mnemonic recovery phrase. BIP 39 specifies mnemonic phrases generated from random entropy. An optional passphrase is used with the mnemonic when deriving the seed. The passphrase is not necessarily a single additional word: a different passphrase produces a different seed.[4]
A recovery phrase can restore access without the original device, so disclosure can defeat the protection offered by the hardware. Recovery requires a compatible wallet and the correct backup information; a passphrase-protected wallet also requires the exact passphrase. Losing that passphrase can prevent recovery even when the mnemonic remains available. A device PIN and a recovery passphrase serve different purposes.[5]
Security limits
Key isolation reduces some risks from a compromised host; it does not guarantee that the transaction a user approves is safe. Malicious interfaces, unreadable signing requests and disclosure of backup material remain relevant. In December 2023, malicious Ledger Connect Kit software loaded by decentralized applications induced users to sign asset-draining transactions, according to Ledger’s incident report.[6]
Physical tampering can also target information outside a protected chip. On 13 October 2026, The Record reported Ledger’s account that devices sold through Southeast Asian reseller CryptoBilis contained implants that captured recovery phrases during setup. The Record reported Ledger’s warning that such devices might still pass authenticity checks because the Secure Element remained intact. As of that report, Ledger had not confirmed affected models or total losses. This illustrates a limitation of those checks in the reported attack, rather than proof that every hardware-wallet model is affected.[7]
Devices and research
Trezor and Ledger are examples of hardware-wallet product families. Designs and capabilities vary, so comparisons need to distinguish particular devices and software versions rather than rank entire brands as universally safe.[3][1]
The original Ledger Nano S was introduced in 2016; Ledger announced its retirement from production and replacement by Nano S Plus in 2022.[8]
Joe Grand separately documented reverse engineering of a real-world implant inside a Ledger Nano X; presentation slides were revised on 29 May 2026. The device in that study was identified as Nano X, while the later reseller reporting did not establish an affected model range.[9]
See also
References
- ↑ 1.0 1.1 Bitcoin Developer Guide: Wallets, signing-only wallets and hardware wallets. Accessed 19 October 2026.
- ↑ BIP 174: Partially Signed Bitcoin Transaction Format. Accessed 19 October 2026.
- ↑ 3.0 3.1 Trezor: Clear Signing on Trezor. Accessed 19 October 2026.
- ↑ BIP 39: Mnemonic code for generating deterministic keys. Accessed 19 October 2026.
- ↑ Trezor: What is a passphrase?. Accessed 19 October 2026.
- ↑ Ledger: Security Incident Report, 20 December 2023.
- ↑ Alexander Martin, The Record: Ledger says hardware implant in cryptocurrency wallets stole recovery phrases, 13 October 2026.
- ↑ Ledger: Commemorating The Ledger Nano S, 22 June 2022.
- ↑ Grand Idea Studio: Reverse Engineering a Ledger Nano X Hardware Implant. Accessed 19 October 2026.