TL;DR: Decentralized identity shifts control over identity data toward the user, which forces API security teams to reduce oversharing, rethink identifiers, and rely more consistently on token-based authorisation and claims, according to Curity. The practical impact is that existing API trust models become harder to defend unless identity, access, and token design are tightened together.
At a glance
What this is: This is an analysis of how decentralized identity changes API security, with the central finding that access decisions must use fewer user attributes, different identifiers, and stronger token-based claims.
Why it matters: It matters because IAM, API security, and digital identity teams will need to redesign authorization data flows so access decisions remain reliable when users control more of their own identity data.
Context
Decentralized identity changes how identity data is presented and consumed in authorization flows. In this model, users disclose less by default and organizations have to make access decisions with fewer assumptions about who is supplying the data and why.
The practical issue for API security is not the identity format itself, but the control model behind it. If access decisions still depend on overshared attributes, email-based identifiers, or context outside the token, the authorization layer becomes harder to trust when the identity source becomes user-directed rather than centrally curated.
Curity's framing is about the interaction between decentralized identity and API security, not a standalone wallet story. That makes the article relevant to teams that already use OAuth and OpenID Connect but need to reconsider what they put into tokens and what they require at authorization time.
Key questions
Q: How should security teams design API authorisation for decentralized identity?
A: They should base decisions on the smallest trusted set of claims, validate the issuer behind each credential, and avoid depending on context outside the token. The goal is to keep authorisation deterministic and auditable even when users present identity through wallets or other portable credentials. That reduces leakage and makes policy enforcement easier to review.
Q: Why does decentralized identity increase authorization risk if teams overcollect data?
A: Because the more identity data an API depends on, the more it inherits disclosure and trust problems that decentralized identity is trying to reduce. If access only needs one attribute, collecting several more expands exposure without improving the decision, which makes the authorization layer harder to defend.
Q: What breaks when email is the primary identifier in decentralized identity flows?
A: Email stops being a reliable assumption when users can present wallet credentials or authenticate without prior registration. That creates ambiguity between account lookup, uniqueness, and proof of identity, so teams need identifier models that do not depend on one legacy field doing all three jobs.
Q: What is the difference between token claims and contextual identity data in APIs?
A: Token claims are issuer-asserted data embedded for authorization, while contextual identity data is information the API infers from the session, request, or surrounding system state. For decentralized identity, the safer model is to base access on claims because they preserve a clearer trust boundary.
Technical breakdown
Token-based authorization becomes the anchor
Decentralized identity does not remove the need for authorization; it changes which identity assertions can be trusted at decision time. In API security, the safest pattern remains token-based architecture where claims are issued by the OAuth and OpenID Connect server, not reconstructed from request context. That distinction matters more when users can present credentials from a wallet and control what they reveal. If the API depends on attributes that are not embedded in the token, authorization becomes easier to drift away from its original trust boundary.
Practical implication: Treat the access token as the source of authorization truth and remove policy dependencies on external context attributes.
Oversharing creates avoidable authorization exposure
Decentralized identity makes data minimisation operational, not philosophical. If an access decision only needs country, then postal code is unnecessary and can expose more than the policy requires. The same applies to age-related checks, where teams often collect more personal data than the authorization rule justifies. In a decentralized model, users control disclosure more tightly, so the burden shifts to the API design to request only what the decision actually needs. This reduces privacy exposure while also shrinking the amount of identity data that can be misused downstream.
Practical implication: Review each authorization rule and remove identity attributes that do not materially affect the access decision.
Identifiers and login assumptions will need redesign
Decentralized identity changes onboarding and authentication because the same person may present a wallet credential without a traditional registered account. That breaks the assumption that email or another static identifier is the stable anchor for access control. Where identity and login method are tightly coupled, the organization can end up overloading one field with too many roles: account lookup, uniqueness, and proof of identity. In practice, API and IAM teams need to separate identifier design from authentication method design so access logic does not depend on fragile legacy assumptions.
Practical implication: Decouple user identifiers from login method and validate whether account models can handle wallet-based identity presentation.
Breaches seen in the wild
- Sourcegraph breach 2023: A site-admin token left in a Sourcegraph commit for 47 days let an attacker become admin and offer free access to its APIs and LLM via a proxy.
- Dropbox Sign breach 2024: A compromised back-end service account gave attackers Dropbox Sign customer data, including API keys, OAuth tokens and MFA information.
Read and download The State of NHI & AI Agent Breach Report 2026, covering 200+ breaches impacting Non-Human Identities including AI Agents.
NHI Mgmt Group analysis
Decentralized identity forces API teams to move from identity collection to identity proofing discipline. The article shows that the real change is not only where identity data comes from, but how much of it is necessary for access decisions. That makes overcollection a governance problem as much as a privacy problem, especially when authorization logic still assumes centralised identity intake.
Token content becomes the new trust boundary. When authorization depends on claims, the quality of those claims matters more than the volume of profile data attached to them. This is where API security and identity architecture converge: teams must know which attributes are asserted by the issuer and which are merely convenient but untrusted context.
Email as a durable identifier is no longer a safe default. The article correctly points out that decentralized identity can decouple onboarding from prior registration, which weakens designs that bind account identity to a single identifier or login method. That assumption was already brittle in federated environments and becomes more exposed when wallets and verifiable credentials enter the flow.
API security and decentralized identity will meet at the policy layer, not the transport layer. The shift does not replace OAuth and OpenID Connect, it increases the importance of using them correctly. Teams that treat wallet-based identity as a front-end change will miss the deeper issue: access policy has to be expressed in claims, not inferred from surrounding data.
Named concept: claim-minimised authorization. This article points toward a model where APIs ask only for the identity attributes needed to decide access, nothing more. That concept is becoming a practical design constraint for organizations that want decentralized identity without expanding their data exposure surface.
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What this signals
Claim-minimised authorization: decentralized identity pushes API teams toward policies that ask for fewer attributes and trust only what is actually needed to decide access. That is a design change, not just a privacy preference, because excess claims expand both exposure and policy ambiguity.
Teams should expect identifier models to become less stable as wallet-based presentation and accountless access become more common. The programme implication is to separate account identity, authentication method, and authorization evidence before those assumptions start failing in production.
For practitioners
- Tighten token design around decision-relevant claims Map each API authorization rule to the smallest possible set of claims and move sensitive assertions into tokens issued by the OAuth and OpenID Connect server.
- Remove overshared identity attributes Review whether postal code, age, or similar attributes are actually required for each access decision, and remove any that do not change the policy outcome.
- Decouple identifiers from login methods Test whether email-based identifiers still make sense when users present wallet credentials or authenticate without prior registration.
- Validate token-only authorization paths Check that authorization decisions do not depend on context attributes outside the token, especially in APIs that already use claims for policy enforcement.
Key takeaways
- Decentralized identity changes API security by shifting more disclosure control to the user, which makes oversharing and fragile identifier design more dangerous.
- The central control point becomes the token, because claims asserted by the issuer are more defensible than context-derived identity signals.
- Teams should reduce the number of identity attributes used in access decisions and verify that account models do not depend on a single legacy identifier.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP API Security Top 10 addresses the attack and risk surface, while NIST SP 800-53 Rev 5 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP API Security Top 10 | API2 — Broken Authentication | The article centers on API trust decisions and identity assertions in authorization flows. |
| API10 — Unsafe Consumption of APIs | The piece warns against consuming identity data from untrusted context outside the token. | |
| Recommendation — Use API2 to verify that API authentication and issuer trust are explicit before policy evaluation. Apply API10 to keep authorization dependent on trusted token claims rather than ambient request context. | ||
| NIST SP 800-53 Rev 5 | IA-5 — Authenticator Management | Token and credential design govern how assertions are issued and consumed in the API flow. |
| Recommendation — Manage token and authenticator lifecycles under IA-5 so authorization inputs remain controlled. | ||
| NIST CSF 2.0 | PR.AA-05 — Access Permissions, Entitlements and Authorizations | The article is fundamentally about how access decisions are expressed and enforced. |
| PR.DS-01 — Data-at-rest is protected | The article highlights limiting unnecessary identity data exposure in API flows. | |
| Recommendation — Align authorization rules with PR.AA-05 so only decision-relevant claims influence access. Minimise stored identity attributes under PR.DS-01 to reduce disclosure and replay exposure. | ||
Key terms
- Decentralized Identity: A model where users control portable credentials and present them to applications for verification. Instead of one organisation holding all identity data, trust is distributed across issuers, wallets, and relying parties, which changes how access decisions, recovery, and account linking must be governed.
- Token-Based Authorisation: An access model where the API evaluates signed or otherwise trusted token content before granting access. It works well only when the token carries accurate, minimal, and well-governed claims, because the token becomes the primary representation of trust at runtime.
- Selective Disclosure: Selective disclosure is the practice of sharing only the identity attributes needed for a specific decision. In credential-based systems, it reduces oversharing, lowers retention burden, and limits exposure when a verifier does not need the full record to make a trustworthy judgment.
- Identifier Decoupling: The separation of account identifiers from login methods and identity presentation formats. This matters when users can authenticate with wallet credentials or verifiable credentials, because a single field like email may no longer be a stable anchor for identity governance.
Deepen your knowledge
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Published by the NHIMG editorial team on May 29, 2026.
Updated on October 8, 2026.
NHI Mgmt Group, the independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org