Nikolaos Makriyannis, Cryptography Research Lead at Fireblocks, and Oren Yomtov, Blockchain Research Lead at Fireblocks, present "Small Leaks, Billions Of Dollars: Practical Cryptographic Exploits That Undermine Leading Crypto Wallets" at DEF COM 31.

Multi-Party Computation (MPC) has become a common cryptographic technique for protecting hundreds of billions of dollars in cryptocurrency wallets. MPC algorithms are currently powering the wallets of Coinbase, Binance, Zengo, BitGo, Fireblocks and many other fintechs/banks servicing hundreds of millions of consumers and thousands of financial institutions.

This presentation examines the most common MPC protocols and implementations and shows that securing MPC remains a challenge for most companies.

We show practical key-exfiltration attacks requiring no more than a couple of hundred signatures. Namely, we show three different attacks on different protocols/implementations requiring 256, 16, and *one* signature, respectively.​