Chainspace is a distributed ledger platform for high-integrity and transparent processing of transactions within a decentralized system. Unlike application such as Bitcoin for a currency, or certificate transparency for certificate verification, Chainspace offers extensibility though smart contracts, like Ethereum. However, users expose to Chainspace enough information about contracts and transaction semantics, to provide higher scalability through sharding across infrastructure nodes: our modest testbed of 60 cores achieves 350 transactions per second, as compared with a peak rate of less than 7 transactions per second for Bitcoin over 6K full nodes. Etherium currently processes 4 transactions per second, out of theoretical maximum of 25. Furthermore, our platform is agnostic as to the smart contract language, or identity infrastructure, and supports privacy features through modern zero-knowledge techniques .