Accumulate Protocol is an identity-centric, Delegated Proof of Stake (DPoS) blockchain built to support the digital economy. It does this through interoperability with Layer-1 blockchains, compatibility with enterprise technology stacks, and connectivity to the World Wide Web. Accumulate aims to address the balance between security, scalability, and decentralization by using a chain-of-chains setup. In this model, digital identities that can control keys, tokens, data, and other identities function as separate blockchains. These Accumulate Digital Identifiers (ADIs) can then be processed and verified simultaneously across the Accumulate network. Each ADI is supported by a tiered key structure with varying priority levels, enabling users to adjust their security over time and build more advanced signature authorization rules that broaden the usefulness of multi-signature transactions. A two-token system helps deliver consistent cost expectations for enterprise participants, and anchoring all transactions to Layer-1 blockchains is intended to provide enterprise-level security for all users.