Wrench attack ($5 wrench attack)

The name comes from the webcomic xkcd (No. 538, ‘Security’): instead of cracking an encrypted laptop with a million-dollar computer cluster, the attackers hit the owner with a $5 wrench until he gives up the password.^[1] No cryptography helps if someone forces you to hand over the secret yourself.

Such crimes are rare, but the number of known cases is rising. Jameson Lopp lists publicly reported attacks on owners of bitcoin and other crypto assets; many are never reported. His list records more than twice as many cases for 2025 as for 2024, including the kidnapping of a co-founder of hardware wallet maker LedgerProvider · Hardware walletLedgerMulti-coin hardware wallets from Paris with a secure element – from the Nano S Plus to touchscreens, no Bitcoin-only edition.Hardware manufacturer – no financial licence required · reviewed Sept 2026Price: $59 (Nano S Plus) to $399 (Stax), manufacturer’s prices (as of Sept 2026)On the learning path: Stage 6 · Step 1 – Hardware wallets compared →Our profile →Official website ↗Only buy hardware wallets from the manufacturer or an authorised reseller.× in France in January 2025 (as of September 2026).^[2]

How to protect yourself

• Discretion: don’t talk publicly about your holdings, and don’t show balances on social media. Have hardware wallets delivered to a parcel locker, because shops’ customer data can become public through data leaks.
• Not everything in one place: if the keys of a multisigGlossaryMultisig (multi-signature)A wallet in which several keys jointly control the bitcoin – for example 2 of 3. If one key is lost or stolen, the bitcoin stays safe. In return, setting it up and backing it up is considerably more demanding.On the learning path: Stage 6 · Step 4 – Inheritance & emergency plan →In the glossary →× are kept in different places, nobody can force a withdrawal at a single location.
• Decoy wallet: if you use a passphraseGlossaryPassphrase (the ‘25th word’)An extra word of your choice added to your seed phrase. The same words then produce a completely different wallet. This protects you if someone finds your words – but if you forget the passphrase, access is lost for good.On the learning path: Stage 5 · Step 3 – Backing up your seed phrase →In the glossary →×, the wallet without the passphrase can hold a small amount as a distraction.
• At home: don’t keep seed backups out in the open, and don’t label them ‘Bitcoin’.