Turnkey for Agent Identity (ERC-8004, SIW, and empowering trustless AI)

With more than 30,000 agents already registered onchain, ERC-8004 is quickly emerging as foundational infrastructure for autonomous software systems operating on Ethereum. 

The standard has taken shape through collaboration across the ecosystem, with contributors associated with the Ethereum Foundation, MetaMask, Coinbase, Google, and distribution partners such as Mantle.

ERC-8004  introduces a trust and discovery layer designed to provide verifiable onchain identity and reputation for autonomous entities. Its authentication layer, called Sign In With Agent (SIWA), enables agents to prove identity cryptographically by signing challenges with the keys tied to their onchain identity, allowing trustless authentication across services without centralized intermediaries.

At Turnkey, we’re helping to operationalize this standard by supporting the signing primitives, secure key custody, and Agentic Wallets needed for agents to register identities and operate securely across services.

Why agent identity is hard to get right (and how ERC-8004 helps)

As autonomous systems move into production, it is necessary to establish reliable identity, authentication and trust for secure, interoperable agent operations. 

Key challenges include:

• Key custody risk: Agents need persistent cryptographic identity but cannot safely manage private keys on their own.
  
  
• Authentication fragmentation: API keys, centralized directories, and platform credentials create silos that limit interoperability.
  
  
• Reputation portability: Trust signals are often locked inside individual platforms.
  
  
• Policy enforcement complexity: Autonomous systems need operational guardrails without constant human intervention.

ERC-8004 anchors agent identity onchain with auditable ownership, creating continuity across custody models and enabling a portable reputation that persists between platforms. 

ERC-8004 registries

ERC-8004 structures itself into the following three complementary registries that allow agents to be recognized, evaluated, and trusted across platforms without relying on any single application or intermediary:

1. Identity Registry (ERC-721): The identity registry provides persistent onchain identity through tokenized IDs that anchor authentication, discovery, and reputation. 

Its metadata can describe capabilities, interfaces, ownership, and contact methods so agents can communicate how they operate and how they can be reached. IDs can be transferred if operational control changes while preserving auditable history, preventing reputation resets.

2. Reputation Registry: The reputation registry records performance signals onchain, including uptime, reliability, activity, and task success. 

This creates a portable, tamper-resistant reputation that can persist across platforms rather than remaining siloed within individual services. It improves trust and discoverability, although greater transparency introduces privacy considerations.

3. Validation Registry: The validation registry enables third-party verification of agent outputs and activity, separating claims from proof. 

Validators can attest to computations or execution environments using mechanisms like trusted execution environments, zero-knowledge proofs, or similar approaches. This establishes cryptographic accountability by turning assertions about agent behavior into verifiable artifacts.

As autonomous systems begin coordinating, transacting, and delivering services independently, verifiable authentication becomes essential for interoperability, security, and sustained trust. But identity and reputation are only part of the picture. Agents also need a reliable way to prove who they are across services. That’s where SIWA comes in. 

What is SIWA? Authentication for machine identities 

Sign In With Agent (SIWA) acts as the authentication layer for ERC-8004 identities. Agents sign cryptographic challenges using keys tied to their ERC-8004 identity, while counterparties retrieve public keys onchain to verify signatures without intermediaries. 

By anchoring authentication to ERC-8004 identity infrastructure, SIWA enables cross-platform authentication portability and removes dependence on centralized identity providers. At the same time, it shifts responsibility toward secure key custody, policy enforcement, and revocation mechanisms that can operate without centralized control.

Turnkey support for ERC-8004 and SIWA: Agent Identity

Supporting standards like ERC-8004 and Sign In With Agent is less about adding another blockchain feature and more about making autonomous agents usable in real environments. The value shows up in how agents authenticate, transact, and operate safely without introducing operational friction or centralized dependencies.

Secure cryptographic identity without operational risk.
Agents need persistent identity to build reputation, authenticate across services, and transact reliably. 

Turnkey provides the operational signing layer that allows organizations to use ERC-8004 identities without exposing private keys, managing sensitive key material manually, or relying on platform-issued API credentials. In practical terms, this means an agent can prove who it is anywhere SIWA is supported while key custody remains isolated and secure.

One portable identity instead of fragmented credentials.
SIWA authentication allows agents to use a single cryptographic identity across multiple services. Instead of generating and rotating API keys for every integration, an agent signs a challenge tied to its onchain identity. 

Turnkey executes those signatures securely, enabling trustless authentication while simplifying integration overhead, credential management, and operational complexity.

Flexible signing workflows for real-world integrations.
Agents rarely operate in a single ecosystem. Supporting multiple cryptographic standards and raw payload signing allows a single agent identity to function consistently across these environments without fragmented infrastructure or duplicated keys.

Turnkey enables agents to authenticate, register identity, and use Agentic Wallets across networks using the same underlying cryptographic root. This allows teams to deploy portable agent identities anchored to ERC-8004 while maintaining operational flexibility across chains, APIs, and service integrations.

Policy-governed autonomy instead of unmanaged automation.
If left unconstrained, autonomous agents introduce operational risk especially in financial or infrastructure-sensitive environments. 

Turnkey’s Agentic Wallets allow organizations to define how agent identities behave. This can include transaction limits, allowed counterparties, execution constraints, or operational guardrails. The result is automation that can move quickly without sacrificing oversight or control.

Practical outcome for builders.
Instead of thinking about identity plumbing, credential storage, or signing infrastructure, teams can focus on what their agents actually do. ERC-8004 provides the identity standard, SIWA provides authentication, and Turnkey provides the operational layer that keeps those identities secure, portable, and governable in production environments.

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Building enterprise-grade agent identity infrastructure with Turnkey

As agent ecosystems mature, identity infrastructure – and the agentic wallets they control – will increasingly mirror enterprise identity and access frameworks, with structured authentication, permissioning, lifecycle controls, and auditability built in from the start. This shift helps autonomous agents operate securely across platforms without relying on centralized credential providers.

Turnkey supports this model by combining cryptographic identity, policy controls, hardware-backed key protection, cross-chain signing, and scalable authentication infrastructure. Agentic Wallets operate as governed execution environments, bound to persistent identities and constrained by programmable policies, so organizations can deploy agents securely from the outset.

With Turnkey, teams can support autonomous agents without introducing new custody risks or operational complexity. They can deploy agents with persistent cryptographic identity, automated governance controls, and secure authentication workflows from day one.

Explore the documentation to learn how to integrate ERC-8004 identities, implement SIWA authentication, and build scalable, secure agent infrastructure with Turnkey. Whether you’re launching financial agents, enterprise automation workflows, or machine-to-machine services, the tools are in place to get started today.

Start building with Turnkey. 

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