CDS v0.1.0 Specification

Status: Draft (superseded by v0.2.0) Issuer: SignedData.Org License: MIT

1. Overview

The Curated Data Standard (CDS) defines a universal envelope for distributing real-time data from verified sources. Every v0.1.0 CDS event is:

Typed — carries a CDSContentType encoding domain, schema, and version as a MIME-like string
Signed — RSA-PSS SHA-256 signature by the producer, verifiable by any consumer with the issuer public key
Fingerprinted — SHA-256 of the raw upstream API response, proving the source bytes were not altered
Enriched — optional LLM-generated context.summary in the declared language

2. Event envelope

{
  "spec_version": "0.1.0",
  "id":           "<uuid-v4>",
  "content_type": {
    "domain":      "<string>",
    "schema_name": "<string>",
    "version":     "<string>",
    "encoding":    "json"
  },
  "source": {
    "id":          "<source-id>",
    "fingerprint": "sha256:<hex>"
  },
  "occurred_at":  "<iso8601>",
  "ingested_at":  "<iso8601>",
  "lang":         "<bcp47>",
  "payload":      {},
  "context": {
    "summary":      "<string>",
    "model":        "<string>",
    "generated_at": "<iso8601>"
  },
  "integrity": {
    "hash":      "sha256:<hex>",
    "signature": "<base64-rsa-pss>",
    "signed_by": "<issuer-id>"
  }
}

3. Content type

application/vnd.cds.<domain>.<schema>+<encoding>;v=<version>

Domain	MIME example
`weather`	`application/vnd.cds.weather.forecast-current+json;v=1`
`sports.football`	`application/vnd.cds.sports-football.match-result+json;v=1`
`news`	`application/vnd.cds.news.headline+json;v=1`
`finance`	`application/vnd.cds.finance.quote-stock+json;v=1`
`religion.bible`	`application/vnd.cds.religion-bible.verse+json;v=1`
`government.brazil`	`application/vnd.cds.government-brazil.diario-oficial+json;v=1`

4. Signing algorithm

Serialise to canonical JSON — sort_keys=True, UTF-8, excluding integrity and ingested_at
hash = "sha256:" + SHA256(canonical_bytes).hexdigest()
Sign canonical_bytes with RSA-PSS (SHA-256 digest, MGF1, max salt length)
Encode signature as base64
Attach IntegrityMeta { hash, signature, signed_by }

Verification: re-serialise canonical bytes, check hash, verify RSA-PSS signature with the issuer public key published at https://signed-data.org/.well-known/cds-public-key.pem.

5. Registered domains

Domain	Description
`weather`	Weather conditions and forecasts
`sports.football`	Football matches, standings, player stats
`news`	Headlines and articles
`finance`	Quotes, prices, market indices
`religion.bible`	Bible verses and passages
`government.brazil`	Brazilian government data

6. SDK conformance

A conformant SDK MUST:

Implement CDSEvent with all required fields
Implement canonical serialisation excluding integrity and ingested_at
Support RSA-PSS SHA-256 signing and verification
Expose CDSSigner, CDSVerifier, and BaseIngestor

Reference implementations:

Python: pip install signeddata-cds
TypeScript: npm install @signeddata/cds-sdk

7. Versioning

spec_version uses semver. Breaking changes increment the major version. content_type.version versions domain schemas independently.