Enlarge / Simplified figurative process of a Cryptocurrency transaction. (credit: Mikael Häggström / Wikimedia) Researchers have defeated a key protection against cryptocurrency theft with a series of attacks that transmit private keys out of digital wallets that are physically separated from the Internet and other networks. Like most of the other attacks developed by Ben-Gurion University professor Mordechai Guri and his colleagues, the currency wallet exploits start with the already significant assumption that a device has already been thoroughly compromised by malware.