An attacker gained access to Keystone's website and stole the cryptographic key used by Keystone hardware wallets to verify their authenticity. This key is used in an online verification process that allows owners to confirm their device is genuine. With this key, an attacker could create counterfeit Keystone hardware wallets that pass the legitimacy check, potentially tricking buyers into trusting fake devices. If a user trusts a counterfeit device, their cryptocurrency could be stolen. In response, Keystone announced it will destroy all 18,835 affected hardware wallets. The incident highlights the risk of supply-chain and device-integrity attacks targeting cryptocurrency hardware wallet manufacturers.