Summary: Enterprises are missing audit deadlines and burning budget because certifications and badges are still PDFs and database flags instead of verifiable, privacy‑preserving credentials. Here’s how we implement production‑grade Soulbound Tokens (SBTs) that interoperate with W3C Verifiable Credentials 2.0 and enterprise identity stacks—so you ship on time, reduce verification costs, and meet SOC 2/ISO 27001 without locking into a single vendor.

Target audience: Enterprise (L&D, HR, Compliance, IT Security). Keywords used intentionally: SOC 2, ISO 27001, GDPR, FERPA, SSO/OIDC, procurement, SLAs, TCO.

Soulbound Tokens (SBTs) for Digital Certifications and Badges

Pain

Your org issues thousands of professional certifications or internal compliance badges (HIPAA, PCI DSS, secure coding, safety training). Yet:

• Revocation is brittle: when a user changes employers or wallets, your “badge” can’t be rotated without manual exceptions.
• Audit evidence takes weeks: screenshots and LMS exports don’t satisfy SOC 2/ISO 27001 auditors without a verifiable trail.
• Vendor lock‑in: proprietary badge platforms don’t interoperate with enterprise SSO, eIDAS wallets, or HRIS (Workday, SAP, Oracle).
• Privacy landmines: storing PII on-chain is a GDPR/FERPA risk; but pure off‑chain links lack integrity, so verifiers don’t trust them.

Meanwhile, the standards your auditors and procurement teams now expect are already live and dated: W3C Verifiable Credentials Data Model 2.0 became a W3C Recommendation on May 15, 2025; OpenID for Verifiable Credential Issuance 1.0 moved to Final Specification in 2025 with self‑certification beginning February 2026; and NIST SP 800‑63‑4 finalized in July 2025 explicitly recognizes subscriber‑controlled wallets in federation models. (w3.org)

Agitation

Miss these shifts and you’ll feel it in hard outcomes:

• Missed renewal deadlines: EU eIDAS 2.0 requires each Member State to make certified European Digital Identity Wallets (EUDI) available by 2026; your verifiers (universities, regulators, platforms) will demand wallet‑native credentials, not PDFs or proprietary badge URLs. (consilium.europa.eu)
• Failed RFPs: RFPs and third‑party risk teams increasingly ask for W3C VC 2.0, OIDC4VCI/4VP, and revocation via Bitstring Status Lists—check‑the‑box items you can’t fake. (w3.org)
• Audit exposure: under NIST 800‑63‑4 and modern privacy guidance, issuing credentials without selective disclosure (SD‑JWT/BBS+) or revocation telemetry raises red flags; fines and remediation erase any savings from “quick win” badge vendors. (pages.nist.gov)
• L2 economics are here; your ops aren’t: post‑Dencun L2 fees make verifiable issuance cheap at scale, but only if your contracts and issuance pipelines are optimized for ERC‑1155 batching and rollup fee markets (e.g., Base’s minimum base fee policy). Otherwise, “gas‑optimized” decks turn into surprise spend. (tradingview.com)

Bottom line: every quarter you delay increases verification costs, extends audit cycles, and cedes procurement leverage to point solutions that won’t pass next year’s interoperability tests.

Solution

7Block Labs implements a standards‑first SBT credential stack that plugs into your identity and audit workflows without crypto jargon—or vendor lock‑in.

We combine three layers:

1. On‑chain attestation and binding
2. Off‑chain credential formats your auditors recognize
3. Privacy‑preserving verification flows that work with enterprise SSO and wallets

1) On‑chain: robust, minimal, and revocable SBTs

• Interface choices by use case:

  • ERC‑5192 (Minimal Soulbound) for “always‑locked” badges with a simple locked() check (EIP‑165 discoverable). Ideal for completion badges that are never transferable. (eips.ethereum.org)
  • ERC‑5484 (Consensual SBT) when you need immutable, per‑token burn policies (issuer‑burnable, holder‑burnable, or both) to support key rotation or policy revocation without transfers. (eip.fun)
  • ERC‑5633 (1155 extension) where you batch‑mint multi‑type certifications at scale (e.g., role matrices), mixing soulbound and transferable IDs in one contract. (eips.ethereum.org)

• Attestation rail: Ethereum Attestation Service (EAS) to anchor credential hashes and status without leaking PII. Schemas define your badge fields; resolvers enforce on‑chain rules; and attestations can be referenced by SBT token IDs for revocation and audit trails. (easscan.org)

• Wallet/signature compatibility: EIP‑712 structured data for issuance consent flows; smart contract wallet compatibility via EIP‑1271 signature checks where needed. (eips.ethereum.org)

• Rollup economics: deploy on an L2 with predictable fees (we often pick Base for enterprise pilots due to Coinbase custody/fiat rails and documented minimum base fee controls that keep common tx costs around fractions of a cent at moderate ETH prices). (docs.base.org)

2) Off‑chain: W3C VC 2.0 credentials your verifiers can trust

• We issue a W3C Verifiable Credential 2.0 alongside the SBT, signed with either:

  • Data Integrity (Ed25519/ECDSA cryptosuites), or
  • JOSE/COSE (JWT/CBOR) with Selective Disclosure JWT (SD‑JWT) for “show only what’s needed” verifications. (w3.org)

• Privacy‑preserving presentations:

  • SD‑JWT is now an IETF standard (RFC 9901, Nov 2025): recipients reveal only required claims (e.g., “cert current,” “role=Senior Engineer”), not the entire transcript. (rfc-editor.org)
  • BBS+ selective disclosure is tracking toward standardization in W3C’s Data Integrity BBS Cryptosuites—useful for unlinkable proofs in regulated contexts. (w3.org)

• Revocation/compliance:

  • We maintain a Bitstring Status List and/or EAS‑backed revocation schema so verifiers can check status instantly without pinging your LMS. This meets VC 2.0 best practices for privacy‑preserving revocation. (w3.org)

• LMS/HRIS fit:

  • Open Badges 3.0 aligns to VC 2.0, so your existing L&D assets can be upgraded rather than rebuilt. We implement Displayer/Verifier services to 1EdTech conformance. (imsglobal.org)

3) Interop and federation: OIDC‑native for enterprise SSO

• Issuance and presentation via OpenID for Verifiable Credential Issuance/Presentations (OIDC4VCI/4VP) so your SSO goes beyond login to verifiable claims. The spec reached Final in 2025; self‑cert opens February 2026—procurement and InfoSec care about this checkbox. (openid.net)

• Regulatory alignment: NIST SP 800‑63‑4 (final July 2025) acknowledges subscriber‑controlled wallets in federation models; our flows map to AAL/FAL targets and your privacy risk register. (pages.nist.gov)

• EU‑readiness: eIDAS 2.0/EUDI wallet timelines mean cross‑border verifiers will expect wallet‑presented credentials by 2026; our stack issues compatible VCs and works with OpenID conformance profiles used by EUDI pilots. (consilium.europa.eu)

---

Architecture at a glance

• Smart contracts: ERC‑5192/5484/5633, EAS schema registry, and policy resolvers.
• Issuer: OIDC4VCI issuer + VC signing service (Data Integrity or SD‑JWT).
• Holder: Enterprise wallet or EUDI wallet; account‑abstracted UX where appropriate.
• Verifier: OIDC4VP verifier + status checkers (Bitstring list + EAS).
• Storage: PII off‑chain; on‑chain holds hashes, status bits, and public badge metadata only.
• Audit: append‑only issuance logs; on‑chain events + signed VC issuance receipts.

We deliver this via our custom stacks and the following offerings:

• End‑to‑end issuance and verification via our web3 development services and smart contract development.
• Security and compliance hardening via our security audit services.
• HRIS/LMS/IdP connectors through our blockchain integration.
• Multi‑chain badge programs with our cross‑chain solutions development.

---

Practical examples with precise implementation details

Example A: University diplomas, HR‑verifiable in under 200 ms

• Diploma issuance: mint ERC‑5484 SBT for each graduate; burnAuth=Both (issuer or holder) to allow key rotation; tokenURI points to non‑PII metadata. (eip.fun)
• VC 2.0: issue a “DegreeCredential” (Data Integrity, Ed25519) with a Bitstring Status List URL; store VC hash in an EAS attestation linked to tokenId. (w3.org)
• Verification: employers use OIDC4VP to request disclosure of “degree=BS CS, validUntil>=now” only; SD‑JWT for selective disclosure where HR only needs fields relevant to job qualifications. (openid.net)
• Address rotation: holder requests burn‑and‑reissue via ERC‑5484; we emit Burn event, update Status List, and re‑mint identical badge to the new address with a new EAS attestation referencing the same VC hash lineage. (eip.fun)

Example B: Regulated workforce training (HIPAA/PHI‑adjacent), GDPR/FERPA safe

• Contract: ERC‑5633 multi‑type badge contract (e.g., HIPAA‑101, Security‑Awareness‑2026) with isSoulbound(id)=true. Batch mint to cohorts monthly. (eips.ethereum.org)
• VC 2.0: one credential per employee with status bits per module; revocation via Bitstring Status List. No training scores on‑chain; only module IDs and completion timestamps in VC. (w3.org)
• Wallets: company SSO with OIDC4VP; NIST 800‑63‑4 alignment for authentication assurance; time‑boxed presentations for audits. (pages.nist.gov)
• Privacy: SD‑JWT proofs for “completed within 12 months” without revealing course names if not necessary. (rfc-editor.org)

Example C: Partner certification program (channel/ISV), global acceptance

• Contracts: ERC‑5192 minimal SBTs with locked()=true for each certification tier; easy discoverability via EIP‑165. (eips.ethereum.org)
• Issuance: OIDC4VCI from the partner portal; HRIS sync creates VCs and mints SBTs on Base for sub‑cent issuance and predictable fee policy. (docs.base.org)
• Verification: distributors verify via OIDC4VP; revocation via EAS attestations and Bitstring Status List; compliant with eIDAS 2.0 wallet acceptance in EU rollouts. (easscan.org)

---

Code: minimal, audit‑friendly Solidity

ERC‑5192‑based SBT with EAS anchoring and consent via EIP‑712. We harden transfers and expose explicit revoke() with role‑based access and EAS status update.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import {AccessControl} from "@openzeppelin/contracts/access/AccessControl.sol";
import {IERC165} from "@openzeppelin/contracts/utils/introspection/IERC165.sol";

// ERC-5192 minimal soulbound interface
interface IERC5192 is IERC165 {
    event Locked(uint256 tokenId);
    event Unlocked(uint256 tokenId);
    function locked(uint256 tokenId) external view returns (bool);
}

// EAS minimal anchor (interface subset)
interface IEAS {
    function attest(bytes32 schema, bytes calldata data) external returns (bytes32 uid);
    function revoke(bytes32 schema, bytes32 uid, bytes calldata data) external;
}

contract SoulboundCert is ERC721, AccessControl, IERC5192 {
    bytes32 public constant ISSUER_ROLE = keccak256("ISSUER_ROLE");
    IEAS public immutable eas;
    bytes32 public immutable schemaId;

    mapping(uint256 => bool) private _locked;        // always true post-mint
    mapping(uint256 => bytes32) public vcUID;        // EAS attestation UID per token

    constructor(address eas_, bytes32 schema_) ERC721("EnterpriseCert", "ECERT") {
        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
        _grantRole(ISSUER_ROLE, msg.sender);
        eas = IEAS(eas_);
        schemaId = schema_;
    }

    function supportsInterface(bytes4 iid) public view override(ERC721, AccessControl, IERC165) returns (bool) {
        return iid == type(IERC5192).interfaceId || ERC721.supportsInterface(iid) || AccessControl.supportsInterface(iid);
    }

    function locked(uint256) external pure override returns (bool) {
        return true; // Minimal ERC-5192: always locked after mint
    }

    function issue(address to, uint256 tokenId, bytes calldata vcAnchoredData) external onlyRole(ISSUER_ROLE) {
        _safeMint(to, tokenId);
        _locked[tokenId] = true;
        emit Locked(tokenId);
        vcUID[tokenId] = eas.attest(schemaId, vcAnchoredData); // anchors hash/status pointer
    }

    function revoke(uint256 tokenId, bytes calldata vcRevokeData) external onlyRole(ISSUER_ROLE) {
        bytes32 uid = vcUID[tokenId];
        require(uid != bytes32(0), "No VC UID");
        eas.revoke(schemaId, uid, vcRevokeData);
        // Burn to reflect revocation; re-issue on rotation if needed
        _burn(tokenId);
    }

    // Block transfers per SBT semantics
    function _update(address to, uint256 tokenId, address auth) internal override returns (address) {
        address from = super._update(to, tokenId, auth);
        if (from != address(0) && to != address(0)) revert("SBT: non-transferable");
        return from;
    }
}

Why this design:

• ERC‑5192 keeps the surface area small for audits. (eips.ethereum.org)
• EAS anchoring separates PII from chain state while giving auditors a cryptographic trail. (easscan.org)
• Revocation is explicit, not “soft‑deleted,” and can be mirrored in your VC Bitstring Status List. (w3.org)

---

Implementation playbook (what we actually do in 90 days)

• Week 0–2: Requirements and risk

  • Map credentials to VC 2.0 contexts; classify PII; pick cryptosuite (SD‑JWT for selective disclosure vs Data Integrity BBS+ if unlinkability is mandatory). (w3.org)
  • Define SBT interface per credential (5192 vs 5484 vs 5633). (eips.ethereum.org)

• Week 3–6: Build and integrate

  • Smart contracts + EAS schemas; audits via our security audit services.
  • OIDC4VCI issuer and OIDC4VP verifier; SSO with your IdP. Conformance plan aligned with OpenID’s 2026 self‑cert program. (openid.net)
  • HRIS/LMS connectors and Open Badges 3.0 displayers. (imsglobal.org)

• Week 7–10: Pilot

  • Batch issuance on an L2 (often Base) with fee controls; gas/throughput SLAs. (docs.base.org)
  • Auditor dry‑run: produce evidence packs (on‑chain events, EAS attestations, VC status lists) mapped to SOC 2/ISO 27001 controls.

• Week 11–13: Harden and scale

  • Pen tests, disaster recovery, and “holder rotation” runbooks (ERC‑5484 burn‑and‑reissue where applicable). (eip.fun)
  • Procurement package: architecture, DPIA (GDPR), data‑flow diagrams, and conformance roadmaps.

We deliver with our custom blockchain development services, web3 development services, and blockchain integration.

---

Best emerging practices we recommend (and implement)

• Keep PII off‑chain. Put only hashes, status, and public metadata on-chain; use VC 2.0 for the claims. This aligns with GDPR data minimization and makes audits simpler. (w3.org)
• Prefer ERC‑5484 over custom transfer reverts when you need user consent and burn policy clarity; auditors understand the burn‑auth semantics. (eip.fun)
• Standardize revocation: VC Bitstring Status Lists + EAS revocation attestation; avoid bespoke APIs that break verifiers. (w3.org)
• Use SD‑JWT for selective disclosure today; consider BBS+ where unlinkability is required and your verifier stack supports it. (rfc-editor.org)
• Batch with ERC‑1155 (5633) if you issue many types each cycle; combine with rollup fee windows and predictable L2 base fee policies. (eips.ethereum.org)
• Plan for eIDAS/EUDI wallet interop and OpenID conformance—procurement will ask. (consilium.europa.eu)
• If you need anonymous attestations (e.g., bias‑reduced hiring screens), add ZK‑proof options (Semaphore/MACI) layered on VC possession, not as a replacement for it. (docs.semaphore.pse.dev)

---

ROI and GTM metrics we sign into pilot SLAs

We avoid vanity metrics. These are the “money phrases” that matter to your CFO and auditors:

• Verification cost per check: target ≥80% reduction vs. manual HR/email checks by moving to OIDC4VP + automated status list lookups. (openid.net)
• Issuance throughput: ≥10,000 credentials/hour on L2 with ERC‑1155 batching; no weekend cutovers. (eips.ethereum.org)
• Audit cycle time: reduce evidence prep from weeks to <48 hours using on‑chain events, EAS UIDs, and VC status lists. (easscan.org)
• Compliance coverage: map 100% of credential workflows to NIST 800‑63‑4 federation and privacy controls; document DPIA and retention policies. (pages.nist.gov)
• Interoperability readiness: VC 2.0 + OIDC4VCI/4VP alignment with a 2026 self‑cert plan; mitigate RFP risk. (w3.org)

We’ll structure the pilot to measure these with crisp dashboards and give Procurement the artifacts they need.

---

Procurement checklist (what your RFP should require)

• Standards: ERC‑5192/5484/5633, VC 2.0, OIDC4VCI/4VP, SD‑JWT (and/or Data Integrity), EAS for attestations. (eips.ethereum.org)
• Compliance: SOC 2/ISO 27001 mapping, NIST 800‑63‑4 alignment, GDPR/FERPA DPIA, revocation with Bitstring Status List. (pages.nist.gov)
• Interop: EUDI wallet compatibility by 2026; OpenID self‑cert plan. (consilium.europa.eu)
• Economics: L2 issuance with documented fee controls (e.g., Base minimum base fee). (docs.base.org)
• Security: independent audits, key management, and incident runbooks; change logs and version pinning for cryptosuites.

---

What you get with 7Block Labs

• A production‑grade SBT + VC 2.0 credentialing system that your auditors, HR, and regulators can verify independently.
• Interoperability that outlives any single wallet, LMS, or badge vendor.
• Architecture and code that balance Solidity pragmatism with privacy‑preserving ZK options—tied to ROI and procurement outcomes, not hype.

Explore our smart contract development, web3 development services, blockchain integration, and security audit services to see how we ship this in your stack.

Call to action: Book a 90-Day Pilot Strategy Call.