V2: Verification and Signature #25

kimdhamilton · 2017-02-16T22:45:30Z

Updated per RWoT 2017 conference, where it was decided to create a MerkleProof2017 signature suite. That spec is still in draft, but this new proposal will fit the proposed structure.

See comment on 4/24.

Goals

Verification and signature should be explicit and allowed to vary, to support (at least) differing choices of:
- proof types, e.g. Proof of Publication, Chainpoint
- crypto key types
- blockchain
- domain-specific concerns
Update standard to ensure at issuing, view, and verifying time, all properties have been mapped at property in the JSON-LD context. Verification should warn (at least) or fail if there are additional properties. This is because of dropping of unmapped properties during JSON-LD canonicalization. See RDF Dataset Normalization

Non-goals

These changes will not add reference implementations for any of the variations described above. The goal is to help make the blockcerts standard more portable across domains, blockchains, etc, in response to community requests
The ideal solution is to use IPFS/IPNS for storage of certain certificate elements, but that's premature for this phase of the standard. Instead, future-proof to allow such extensions.
TBD: signature chains

Verification

Blockcerts verification types will be added as OBI extensions

"verification": {
    "type": "MerkleProofVerification2017",
    "creator": "https://example.org/issuer/keys/1.9.1.1"
  }

Signature

This is out of date. See updated version of signature, comment on 4/24/2017

About signature type

Signature will use the blockcerts type LinkedDataEcdsaKoblitzSignature. This is an extension to EcdsaKoblitzSignature2016 type, but adapted for OBI extension.

This type is also heavily borrowed from Proof of Publication; however, the latter is still in draft and Blockcerts requires slight variations including the ability to continue using chainpoint for the Merkle proof. Therefore, this currently (re)defines elements in the blockcerts context.


  "signature": {
    "type": ["EcdsaKoblitzSignature2016", "Extension", "LinkedDataEcdsaKoblitzSignature"],
    "created" = "2017-03-24T21:48:24Z",
    "creator" = "ecdsa-koblitz-pubkey:1LGpGhGK8whX23ZNdxrgtjKrek9rP4xWER",
    "merkleProof": {  
      // currently supported type is chainpoint, but will include others like PoP (https://web-payments.org/specs/source/pop2016/)
      ...
    },
    "signatureValue": "OGQzNGVkMzVm4NTIyZTkZDY...NmExMgoYzI43Q3ODIyOWM32NjI="
  }

Example Signatures

Signature with chainpoint

  "signature": {
    "type": ["EcdsaKoblitzSignature2016", "Extension", "LinkedDataEcdsaKoblitzSignature"],
    "created" = "2017-03-24T21:48:24Z",
    "creator" = "ecdsa-koblitz-pubkey:1LGpGhGK8whX23ZNdxrgtjKrek9rP4xWER",
    ....
    "merkleProof": {
      "type": "ChainpointSHA256v2",
      "merkleRoot": "68f3ede17fdb67ffd4a5164b5687a71f9fbb68da803b803935720f2aa38f7728",
      "targetHash": "c9ead76a54426b4ce4899bb921e48f5b55ea7592e5cee4460c86ebf4698ac3a6",
      "proof": [{
        "right": "7fef060cb17614fdfddd8c558e102fbb96433f5281e96c80f805459773e51163"
      }],
      "anchors": [{
        "sourceId": "8623beadbc7877a9e20fb7f83eda6c1a1fc350171f0714ff6c6c4054018eb54d",
        "type": "BTCOpReturn"
      }],
    }
   ...
  }

Example Signature with PoP

"signature": {  
    "type": ["EcdsaKoblitzSignature2016", "Extension", "LinkedDataEcdsaKoblitzSignature"],
    "created" = "2017-03-24T21:48:24Z",
    "creator" = "ecdsa-koblitz-pubkey:1LGpGhGK8whX23ZNdxrgtjKrek9rP4xWER",
    "merkleProof": {  
      "type": "PoP2016",
      "ledger": "bitcoin",
      "transactionId": "7ea0cef6a31c65590d6c1d61abbfa02d3006da6509a018cdbc709d0a781a7c28",
      "merkleRoot": "80ab866e989432e023b51e866545c141e00d456e59fa1e253fac3a561e1a6c14",
      "proof": [{
        "merkleParent": "f51cd07057a813f92a33a05ed58a0f26600d2205f9c590f3461f94bd8451b567",
        "merkleLeftSibling": "247911c653b43a2d13010538c7eae52e500a556448f17384d636857b2b63ae45",
        "merkleRightSibling": "93ca67aea78e996fb9e10368243110c6f037143dbeec726de0b9172766427399"
      }, {
        "merkleParent": "e6a881dd07c479eaf2afdd26ae34b441af2fede85c90b5281346846a5dc81bca",
        "merkleLeftSibling": "44c66b49e4024bf1ba370c38a3655f2094cd110caf91636f749d9e0385fb9272",
        "merkleRightSibling": "93ca67aea78e996fb9e10368243110c6f037143dbeec726de0b9172766427399"
      }]
    },
    // subsequent fields from https://web-payments.org/vocabs/security#signature
    "signatureValue": "OGQzNGVkMzVm4NTIyZTkZDY...NmExMgoYzI43Q3ODIyOWM32NjI="
  }

Clarifications and TBD

Should the part of the certificate that's hashed and put on the blockchain announce which signature scheme will be used in the issuer verification node? This would prevent fraud in the cause of an attacker creating a fake "signature suite" that allows the signature to validate.
The verification process could also enforce that the signature suite is one of the expected types, which would allow us to drop this.

The text was updated successfully, but these errors were encountered:

westurner · 2017-02-26T17:23:58Z

ld-signatures
- Spec: https://w3c-dvcg.github.io/ld-signatures/
- https://w3c-dvcg.github.io/ld-signatures/#terminology
- signature suite
  - https://w3c-dvcg.github.io/ld-signatures/#dfn-signature-suite
  - A specified set of cryptographic primitives typically consisting of a canonicalization algorithm, a message digest algorithm, and a signature algorithm that are bundled together by cryptographers for developers for the purposes of safety and convenience.
  - https://w3c-dvcg.github.io/ld-signatures/#signature-suites
    - At a minimum, a signature suite must have the following attributes:
      - @id
        
        https://w3id.org/security#LinkedDataSignature2015
      - @type: SignatureSuite
      - canonicalizationAlgorithm
        
        https://w3id.org/security#URDNA2015.
      - digestAlgorithm
        
        http://example.com/digests#sha512
      - signatureAlgorithm
        
        http://www.w3.org/2000/09/xmldsig#rsa-sha256
- signature set
  - https://w3c-dvcg.github.io/ld-signatures/#signature-sets
  - A signature set is useful when the same data needs to be signed by multiple entities, but where the order of signatures does not matter, such as in the case of a set of signatures on a contract. A signature set, which has no order, is represented by associating a set of signatures with the signature key in a document.
- signature chain
  - https://w3c-dvcg.github.io/ld-signatures/#signature-chains
  - A signature chain is useful when the same data needs to be signed by multiple entities and the order of when the signatures occurred matters, such as in the case of a notary counter-signing a signature that had been created on a document. A signature chain, where order must be preserved, is represented by associating an ordered list of signatures with the signatureChain key in a document.

# EXAMPLE 4: A signature chain in a Linked Data document
{
  "@context": "https://w3id.org/identity/v1",
  "title": "Hello World!",
  "signatureChain": [{
    "type": "RsaSignature2015",
    "creator": "http://example.com/i/pat/keys/5",
    "created": "2011-09-23T20:21:34Z",
    "domain": "example.org",
    "nonce": "2bbgh3dgjg2302d-d2b3gi423d42",
    "signatureValue": "OGQzNGVkMzVm4NTIyZTkZDY...NmExMgoYzI43Q3ODIyOWM32NjI="
  }, {
    "type": "RsaSignature2015",
    "creator": "http://bank.example.com/notary/keys/7f3j",
    "created": "2011-09-23T20:24:12Z",
    "domain": "example.org",
    "nonce": "83jj4hd62j49gk38",
    "signatureValue": "yZTkZDYOGzNGVkMVm4NTIQz...M32NjINmExMDIyOWgoYzI43Q3O="
  }]
}

[edit]

# EXAMPLE 5: A complete example of a signature suite

{
  "id": "https://w3id.org/security#LinkedDataSignature2015",
  "type": "SignatureSuite",
  "canonicalizationAlgorithm": "https://w3id.org/security#URDNA2015",
  "digestAlgorithm": "http://example.com/digests#sha512",
  "signatureAlgorithm": "http://www.w3.org/2000/09/xmldsig#rsa-sha256"
}

kimdhamilton · 2017-02-27T00:35:45Z

updated to clarify use of EcdsaKoblitzSignature2016

kimdhamilton · 2017-02-28T00:34:52Z

per this pyld issue, we can use vocab to create a fallback context to flag unmapped properties

fallback_ctx = {"@vocab": "http://fallback.org/"}

westurner · 2017-02-28T02:00:52Z

"RDFa Core Initial Context"
- https://www.w3.org/2011/rdfa-context/rdfa-1.1
- https://www.w3.org/2013/json-ld-context/rdfa11

westurner · 2017-03-23T04:06:32Z

"RDF integration: schema.org/Certification and schema.org/BadgeCriteria"
RDF integration: schema.org/Certification and schema.org/BadgeCriteria openbadges-specification#9 (comment)

.

"schema.org/Course -> schema.org/Credential"

kimdhamilton · 2017-03-23T19:03:13Z

Thanks @westurner! I'm catching up on the references you included. I wanted to confirm one takeaway I had, which is that our terminology is sometimes lax. For example, above I use "certificate" in the informal sense instead of the more precise "Credential". I agree that I should update that, but I also wanted to see if there are other nuances I missed.

westurner · 2017-03-24T12:11:30Z

"Credential" as the super type:

CTI: https://github.com/CredentialTransparencyInitiative/vocabularies/blob/master/credentialType.ttl
Course, CourseInstance, EducationEvent [Schema.org Course Extension] schemaorg/schemaorg#195 (comment)
- westurner/schemaorg@1f268fc
  - Credential (that could be earned)
  - CredentialInstance (issuer={Person/Organization}, issuee={P/O}, validFrom, validUntil, ...)
  - e.g. Credential > Certificate > Diploma
    e.g. Credential > AcademicDegree > BachelorDegree
    e.g. Credential > Certification
    - note that https://schema.org/Course was released today (without grantsCredential or Credential yet)
      - https://schema.org/docs/releases.html#v3.2
        
        http://blog.schema.org/2017/03/schemaorg-32-release-courses-fact.html

WebID

| Wikipedia: https://en.wikipedia.org/wiki/WebID
| Spec: https://www.w3.org/2005/Incubator/webid/spec/
| Spec: https://www.w3.org/2005/Incubator/webid/spec/identity/
- https://www.w3.org/2005/Incubator/webid/spec/identity/#publishing-a-webid-profile-using-the-rdfa-html-notation
The Cert Ontology 1.0

The Cert Ontology 1.0 :

https://www.w3.org/ns/auth/cert#
- https://www.w3.org/ns/auth/cert#Certificate
  - foaf:Document > cert:Certificate > {cert:X509Certificate, cert:PGPCertificate}
  - "A certificate is a Document that is signed"
- http://lov.okfn.org/dataset/lov/vocabs/cert

kimdhamilton · 2017-04-24T18:30:35Z

Per decision at RWoT 2017, there will be a separate signature suite for Merkle Proofs, using the Chainpoint v2.0 proof format. Details coming soon. In blockcerts it will look like this:

"signature": {
    "type": ["MerkleProof2017", "Extension"],
    "merkleRoot": "68f3ede17fdb67ffd4a5164b5687a71f9fbb68da803b803935720f2aa38f7728",
    "targetHash": "c9ead76a54426b4ce4899bb921e48f5b55ea7592e5cee4460c86ebf4698ac3a6",
    "proof": [{
        "right": "7fef060cb17614fdfddd8c558e102fbb96433f5281e96c80f805459773e51163"
    }],
    "anchors": [{
      "sourceId": "8623beadbc7877a9e20fb7f83eda6c1a1fc350171f0714ff6c6c4054018eb54d",
      "type": "BTCOpReturn"
    }]
  }

kimdhamilton · 2017-07-20T19:10:12Z

v2 updates are in all branches

This was referenced Feb 16, 2017

Separate Blockcerts contexts into Blockcerts core and OBI extensions #23

Closed

V2: Revocation improvements #24

Closed

kimdhamilton changed the title ~~Verification and Signature (draft)~~ V2: Verification and Signature (draft) Feb 17, 2017

kimdhamilton mentioned this issue Feb 22, 2017

Improve OBI signing step #9

Closed

kimdhamilton mentioned this issue Feb 26, 2017

V2: OBIv2 Alignment #28

Closed

westurner mentioned this issue Mar 23, 2017

Implement "hook" support for package signature verification. pypa/pip#1035

Closed

This was referenced Mar 23, 2017

RDF integration: schema.org/Certification and schema.org/BadgeCriteria 1EdTech/openbadges-specification#9

Open

ENH: Add RDFa, JSON-LD to HTML templates blockchain-certificates/cert-viewer#57

Open

westurner mentioned this issue Mar 24, 2017

ENH: Add RDFa, JSON-LD to HTML templates blockchain-certificates/cert-web-component#4

Open

1 task

westurner mentioned this issue Mar 24, 2017

Course, CourseInstance, EducationEvent [Schema.org Course Extension] schemaorg/schemaorg#195

Closed

11 tasks

kimdhamilton changed the title ~~V2: Verification and Signature (draft)~~ V2: Verification and Signature May 3, 2017

westurner mentioned this issue May 23, 2017

SOLID as a protocol to indentify researchers solid/solid-spec#102

Open

kimdhamilton closed this as completed Jul 20, 2017

westurner mentioned this issue Aug 1, 2017

Unintuitive API for trust/signing a notebook jupyter/nbformat#98

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

V2: Verification and Signature #25

V2: Verification and Signature #25

kimdhamilton commented Feb 16, 2017 •

edited

Loading

westurner commented Feb 26, 2017 •

edited

Loading

ld-signatures

kimdhamilton commented Feb 27, 2017

kimdhamilton commented Feb 28, 2017

westurner commented Feb 28, 2017

westurner commented Mar 23, 2017 •

edited

Loading

kimdhamilton commented Mar 23, 2017

westurner commented Mar 24, 2017 •

edited

Loading

kimdhamilton commented Apr 24, 2017 •

edited

Loading

kimdhamilton commented Jul 20, 2017

V2: Verification and Signature #25

V2: Verification and Signature #25

Comments

kimdhamilton commented Feb 16, 2017 • edited Loading

Goals

Non-goals

Verification

Signature

About signature type

Example Signatures

Signature with chainpoint

Example Signature with PoP

Clarifications and TBD

westurner commented Feb 26, 2017 • edited Loading

ld-signatures

kimdhamilton commented Feb 27, 2017

kimdhamilton commented Feb 28, 2017

westurner commented Feb 28, 2017

westurner commented Mar 23, 2017 • edited Loading

kimdhamilton commented Mar 23, 2017

westurner commented Mar 24, 2017 • edited Loading

kimdhamilton commented Apr 24, 2017 • edited Loading

kimdhamilton commented Jul 20, 2017

kimdhamilton commented Feb 16, 2017 •

edited

Loading

westurner commented Feb 26, 2017 •

edited

Loading

westurner commented Mar 23, 2017 •

edited

Loading

westurner commented Mar 24, 2017 •

edited

Loading

kimdhamilton commented Apr 24, 2017 •

edited

Loading