OpenClaiming Protocol
OpenClaiming is an open protocol for publishing and verifying cryptographically signed claims. An OpenClaim is a small signed JSON document that states something about a subject. Anyone can verify it using the issuer's public key.
The Need for OpenClaiming Protocol
Today many systems need verifiable statements — about identities, roles, permissions, events, and observations. However, most existing standards require complex infrastructure, large schemas, specialized tooling, or centralized registries before anything useful can be published or verified.
As a result, many developers fall back to ad-hoc solutions such as unsigned JSON, custom API responses, proprietary tokens, or opaque database records. These approaches make interoperability difficult and prevent third parties from independently verifying the truth of a statement.
OpenClaiming focuses on a simpler primitive:
A signed claim that anyone can verify.
Instead of introducing new identity frameworks or credential registries, OpenClaiming defines a minimal signed JSON document that can be published anywhere and verified using standard public-key cryptography. This allows systems to exchange verifiable statements without requiring shared infrastructure or prior trust relationships.
This simple primitive can support many common needs:
OpenClaiming intentionally avoids unnecessary complexity. It can coexist with larger credential systems or serve as a lightweight building block inside them. For a comparison with existing standards and approaches, see the comparison section.
What is an OpenClaim?
An OpenClaim is a signed JSON document.
An OpenClaim states:
Example
{
"ocp": 1,
"iss": "https://example.com/alice",
"sub": "https://example.com/bob",
"stm": {
"member": true,
"role": "admin"
},
"nbf": 1712000000,
"exp": 1750000000,
"key": ["https://example.com/.well-known/openclaiming.json#key1"],
"sig": ["BASE64_SIGNATURE"]
}How It Works
Because the signature is public-key based, verification requires no trusted intermediary.
Create
A system creates a claim as a JSON document.
Canonicalize
The JSON document is canonicalized for deterministic serialization.
Sign
The issuer signs the document with a private key.
Publish
The claim is published anywhere — APIs, storage, blockchains.
Verify
Anyone can verify the claim with the issuer's public key.
Key Properties
Simple
Minimal JSON and a small set of fields. No mandatory registries. No complex schemas.
Decentralized
Claims can be published anywhere — .well-known endpoints, APIs, distributed storage, blockchains.
Verifiable
Every claim contains a cryptographic signature that anyone can verify.
Interoperable
Standard JSON and deterministic canonicalization. Implementations can be written in any language.
Example Use Cases
These claims create cryptographic accountability.
Identity Linking
Multiple sites post claims signed by the same key.
Membership
Organizations can publish signed membership records.
Capability Delegation
One party grants permission to another.
Cross-Domain API Calls
Server proves domain control and signs API calls.
Signed Observations
Servers can publish signed observations.
Blockchain Anchoring
OpenClaims can be anchored to blockchains by storing hashes, signatures, and timestamps.
Comparison
OpenClaiming vs other systems
| Feature | Verifiable Credentials | OpenClaim |
|---|---|---|
| Complex schemas | ||
| Required infrastructure | High | Minimal |
| JSON simplicity | Moderate | Very simple |
| Decentralized publishing | ||
| Easy implementation |
Verdict
OpenClaiming can be used as a lightweight credential format or as a building block inside VC systems.
Get Started
To start using OpenClaiming:
Open Source — Contributions welcome
OpenClaiming is released under a permissive open source license to encourage adoption.