A decentralized exchange called AFX Trade, built on Arbitrum, lost about $24 million after an attacker got hold of validator signing keys for a bridge the protocol ran itself. Five hot-validator signatures cleared the quorum needed to approve the withdrawal. The contract logic was not broken; it did exactly what it was told. The weak point was never the code. It was who was allowed to sign, and how many of them could be gotten to at once. Quorum is a number chosen by someone. That choice is where the trust lives.