An estimated $US280 million ($AU365 million) worth of the cryptocurrency ethereum is now locked up after a user accidentally deleted the code necessary to access the digital wallets hosted by the company Parity Technologies.The vulnerability impacted the “multi-sig” digital wallets launched through Parity since July 20.Multi-sig wallets usually contain large sums of money since they are primarily used by startups or large groups looking to prevent any one member of the group from running off with the money.