This is pretty impressive work, hats off! Their extensive whitepaper is absolutely worth reading: <a href="https:&#x2F;&#x2F;www.bigchaindb.com&#x2F;whitepaper&#x2F;bigchaindb-whitepaper.pdf" rel="nofollow">https:&#x2F;&#x2F;www.bigchaindb.com&#x2F;whitepaper&#x2F;bigchaindb-whitepaper....</a> - its full of details of their solution and also has a good collection of background reading material.<p>What is important to note is that they don&#x27;t address the Sybil attack on a technological level:<p>&gt; Deploying BigchainDB in a federation with a high barrier of entry based on trust and reputation discourages the participants from performing an attack of the clones. The DNS system, for example, is living proof of an Internet-scale distributed federation. Appendix C describes how the DNS has successfully run a decentralized Internetscale database for decades.<p>As far as I understand with spending only little time on this matter that&#x27;s the main tradeoff they took compared to fully decentralized databases such as the Bitcoin&#x27;s public ledger and which allow them to scale the performance.