A wrench attack is physical coercion used to force a victim to surrender cryptocurrency access. The name is a reminder that the attacker is not trying to break encryption first; instead, they pressure the person who controls the wallet, recovery phrase, hardware device, or exchange account.
This matters because even strong cryptography can fail under real-world pressure. If an attacker can threaten, kidnap, rob, or intimidate the holder, they may bypass passwords, multi-factor authentication, and cold storage by forcing a live unlock or disclosure of backup material. In practice, defenders reduce risk with tight privacy, limited public exposure of holdings, separate storage of recovery secrets, travel and home security planning, and strong operational discipline around who knows what. A wrench attack is therefore both a cyber-security and personal-safety threat: the weak point is often the human operator, not the wallet software.