"More than $300m of cryptocurrency has been lost after a series of bugs in a popular digital wallet service led one curious developer to accidentally take control of and then lock up the funds.
Unlike most cryptocurrency hacks, however, the money wasn’t deliberately taken: it was effectively destroyed by accident. The lost money was in the form of Ether, the tradable currency that fuels the Ethereum distributed app platform, and was kept in digital multi-signature wallets built by a developer called Parity. These wallets require more than one user to enter their key before funds can be transferred."
https://www.theguardian.com/technology/2017/nov/08/cryptocurrency-300m-dollars-stolen-bug-ether
Unlike most cryptocurrency hacks, however, the money wasn’t deliberately taken: it was effectively destroyed by accident. The lost money was in the form of Ether, the tradable currency that fuels the Ethereum distributed app platform, and was kept in digital multi-signature wallets built by a developer called Parity. These wallets require more than one user to enter their key before funds can be transferred."
https://www.theguardian.com/technology/2017/nov/08/cryptocurrency-300m-dollars-stolen-bug-ether