Cryptocurrency wallets store the wallets private key(s), and hence, are a lucrative target for attackers. With possession of the private key, an attacker virtually owns all of the currency in the compromised wallet. Managing cryptocurrency wallets offline, in isolated ('air-gapped') computers, has been suggested in order to secure the private keys from theft. Such air-gapped wallets are often referred to as 'cold wallets.' In this paper, we show how private keys can be exfiltrated from air-gappe...