Spruce ID

Spruce ID is a suite of open-source software tools and protocols that enable decentralized identity (DID) and verifiable credentials (VCs) for web3 and enterprise applications. It provides the foundational infrastructure for users to create, control, and share their digital identity without relying on centralized authorities. The core mission is to enable user-controlled data and portable reputation across different platforms and blockchains, facilitating trust in digital interactions. Spruce's architecture is built around open standards from the World Wide Web Consortium (W3C), such as Decentralized Identifiers (DIDs) and Verifiable Credentials, ensuring interoperability and broad compatibility.

The Spruce ecosystem consists of several key components. SpruceID Kepler is a user-controlled, cross-chain storage solution for credentials and personal data, acting as a decentralized personal data store. DIDKit is a cross-platform toolkit for working with W3C DIDs and VCs, available in multiple programming languages. Rebase is a developer toolkit for building sign-in with Ethereum and other blockchain-based authentication flows. Together, these tools allow developers to implement features like self-sovereign identity, passwordless login, and selective disclosure of attested information, where users can prove specific claims (e.g., being over 18) without revealing their entire credential.

A primary use case for Spruce ID is implementing the Sign-In with Ethereum (SIWE) standard, which allows users to authenticate to web applications using their Ethereum wallet (like MetaMask) instead of a traditional username and password. This creates a cryptographically verifiable link between a user's blockchain account and their identity within a dApp. Beyond authentication, Spruce enables complex verifiable credential flows, such as a university issuing a tamper-proof digital diploma to a graduate's Kepler storage, which the graduate can then present to a potential employer for instant, cryptographically-verified validation. This moves trust from institutional silos to cryptographic proofs.

Spruce ID differentiates itself through its strong commitment to open standards and interoperability. Rather than creating a proprietary identity system, it provides the building blocks that align with the W3C's vision for a decentralized identity layer for the web. This approach allows credentials issued via Spruce systems to be usable across a wide ecosystem of applications that support the same standards. The project is developed transparently as open-source software, with significant contributions to the broader Decentralized Identity Foundation (DIF) and related standardization efforts, ensuring the technology remains vendor-neutral and community-driven.

In practice, integrating Spruce ID allows enterprises and web3 projects to reduce reliance on brittle email/password databases, minimize data breach risks by not centrally storing sensitive PII, and create more user-friendly onboarding experiences. For users, it offers greater data portability and privacy through selective disclosure. The toolkit is blockchain-agnostic, with initial deep support for Ethereum and compatibility designed to extend to other chains. By providing these developer tools, Spruce ID aims to catalyze the adoption of user-centric identity models, forming a critical piece of infrastructure for a more trustworthy and interoperable digital world.

Spruce ID operates on a core architectural principle of user-controlled data, leveraging decentralized identifiers (DIDs) and verifiable credentials (VCs). A DID is a globally unique identifier, like did:key:z6Mk..., that an individual or entity generates and controls, independent of any centralized registry. Verifiable credentials are digital, cryptographically signed attestations (e.g., a proof of age or membership) that can be issued to a DID holder. The system uses W3C standards to ensure interoperability across different identity networks and applications.

The user experience is managed through wallet-based agents or sign-in protocols. A primary component is Sign-In with Ethereum (SIWE), which allows users to authenticate to web applications using their Ethereum wallet signature instead of a traditional username and password. For more complex data sharing, Spruce's Credential Kit enables applications to request specific VCs, which the user's wallet can selectively disclose. All cryptographic proofs and consent flows happen client-side, ensuring credentials are never stored on Spruce's servers.

Key to its functionality is the Spruce DIDKit, a cross-platform toolkit that provides libraries for issuing, presenting, and verifying credentials. Developers integrate DIDKit to add decentralized identity features to their apps. For data storage, Spruce promotes the User Data Store pattern, where encrypted credentials can be stored in user-controlled locations like IPFS, Ceramic, or even cloud storage, with access governed by the user's keys. This decouples data hosting from data control.

A practical workflow involves three parties: the issuer (e.g., a university issuing a diploma VC), the holder (the user who stores it in their wallet), and the verifier (e.g., an employer's website). The holder presents a cryptographically signed verifiable presentation to the verifier, who uses DIDKit to verify the signatures and the credential's status without contacting the issuer directly. This creates a trust model based on cryptography rather than centralized intermediaries.

Spruce ID also addresses bridging web2 and web3 data through products like SpruceID Kepler, a personal data store. Kepler allows users to grant granular, revocable access to their data—whether from traditional OAuth providers like Google or from blockchain sources—to various applications. This enables a unified, user-centric model for data governance, making Spruce ID a foundational layer for self-sovereign identity (SSI) across the digital ecosystem.