Cryptocurrency exchange Bybit said last week hackers had stolen digital tokens worth around $1.5 billion, in what researchers called the biggest crypto heist of all time.Bybit CEO Ben Zhou said the crypto was taken from a cold wallet a digital wallet usually stored offline and so supposedly more secure that was used for ether tokens.Blockchain research firm Elliptic said the hack was more than double the last-biggest crypto heist and is almost certainly the single largest known theft of any kind in all time.The crypto industry has suffered a series of thefts, prompting questions about the security of customer funds, with hacking hauls totalling more than $2 billion in 2024 the fourth straight year where proceeds have topped more than $1 billion.Here are some of the other major thefts to have plagued the industry since bitcoin was born in 2008.Poly networkHackers stole around $610 million in August 2021 from Poly Network, a platform that facilitates peer-to-peer token transactions. The hackers behind the heist later returned nearly all of the stolen funds.The hack underscored vulnerabilities in the burgeoning decentralised finance DeFi sector, where users lend, borrow and save in digital tokens, bypassing the traditional gatekeepers of finance such as banks and exchanges.Ronin NetworkHackers stole cryptocurrency worth at the time of the hack around $540 million from a blockchain project linked to the popular online game Axie Infinity in March 2022.Ronin, a network that allows the transfer of crypto coins across different blockchains, said that hackers stole some 173,600 ether tokens and 25.5 million USD Coin tokens.CoincheckIn January 2018, hackers stole cryptocurrency then worth around $530 million from Tokyo-based exchange Coincheck. The thieves attacked one of Coinchecks hot wallet a digital folder stored online to drain the funds, drawing attention to security at exchanges.South Koreas intelligence agency said at the time that a North Korean hacking group may have been behind the heist.Mt. GoxIn one of the earliest and most-high profile crypto hacks, bitcoin worth close to $500 million dollars was stolen from the Mt.Gox exchange in Tokyo then the worlds biggest between 2011 and 2014.Mt.Gox, which once handled 80% of the worlds bitcoin trade, filed for bankruptcy in early 2014 after the hack was revealed, with some 24,000 customers losing access to their funds.WormholeDeFi site Wormhole was hit by a $320 million heist last month, with the hackers making off with 120,000 digital tokens connected to the second-largest cryptocurrency, ether.The crypto arm of Chicago-based Jump Trading, which had the year before acquired the developer behind Wormhole, later replaced the funds to make community members whole and support Wormhole now as it continues to develop.Tommy Reggiori Wilkes, Tom Wilson and Elizabeth Howcroft, Reuters