This year, too, we would like to sweeten the Advent season for our readers with an Advent calendar. In a somewhat different form, each door contains a “knowledge bomb”, which will be supplemented on Christmas Day with an extraordinary special prize. Behind the tenth door is the term “Bridge”. To enter the giveaway on the 24th, simply take part in the polls and like the respective Twitter posts. Bridge With the emergence of alternative smart contract platforms such as Solana, Avalanche and Fantom, the ecosystem of decentralized financial applications (DeFi) has increasingly diversified from the pioneer Ethereum into a multi-chain world. An integral part of this “multi-chain” ecosystem are so-called bridges. They allow users to quickly transfer tokens from one blockchain to another. News Largest DeFi hack worth USD 600 million11. August 2021 News Solana Bridge Wormhole suffers $320 million hack4. February 2022 News Axie Infinity’s Ronin network suffers 620 million hack30. March 2022 In the past, however, those bridges turned out to be critical points of attack. This fact was impressively confirmed this year. Just the three largest bridge hacks of the year (Ronin, BNB Bridge & Wormhole) together amounted to over USD 1.5 billion. These bridges thus represent a significant weak point in the blockchain infrastructure and clearly hinder the multi-chain future. Advent calendar day 10Why are blockchain bridges popular points of attack? Bridges are complex pieces of software that can be ruined by tiny errors. The developers of bridges are bad programmers Hacking a bridge is completely legal, unlike other protocols