The document presents Blockcerts, an open standard for issuing and verifying blockchain-based credentials such as certificates and licenses. It outlines the technical processes involved in creating, verifying, and managing these credentials, including mechanisms for revocation and privacy. The document emphasizes the importance of decentralization and interoperability, highlighting upcoming enhancements in future versions.

1. The Open Standard for Blockchain
Credentials
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Anthony Ronning @cycryptr
Blockcerts Dev and Backend
Engineer at Learning Machine
Daniel Paramo @danparamov
Co-Founder of swys, Advisor at
Xertify and Founder of
echoisolutions

2. 1. Empower global SSI communities
2. Open to everyone interested in SSI
3. All content is shared with CC BY SA
SSIMeetup.org
Alex Preukschat @SSIMeetup @AlexPreukschat
Coordinating Node SSIMeetup.org
https://creativecommons.org/licenses/by-sa/4.0/
SSIMeetup objectives

3. Who are we?
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- Blockcerts Developer
- Backend Engineer at Learning
Machine
- Advisor at Trukl.io
- Bitcoin / Lightning Enthusiast
- Former Biz Dev at Learning Machine
- Co-Founder of swys
- Advisor at Xertify
- Founder of Echo Intelligent Solutions
- Helicopter geek

4. Blockcerts is an open standard for building apps that
issue and verify blockchain-based official records.
These may include certificates for civic records,
academic credentials, professional licenses, workforce
development, and more.
What is Blockcerts?
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5. Blockcerts Flow
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1. Issuer invites recipient (url, email, qrcode, etc)
2. Recipient “Adds Issuer” in app, transmitting
blockchain address
3. A credential is created for the recipient, adding
their address inside of the credentials.
Credential is then hashed
4. Recipient receives credential (deep link url,
import json file, etc.)
5. Recipient can then send to a verifier (url if
hosted, json if not)
6. Verifier can verify using open source verifiers or
on blockcerts.org

6. UI - Blockcerts.org
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7. UI - Blockcerts Mobile App
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8. ● Extension to the Open Badges Standard
● JSON-LD File
● Contains information about the issuer, recipient, & achievement
● Hashes all relevant data, creates transaction with hash in the data field, signs.
& broadcasts transaction.
○ Blockchain receipt information is then written back into the credential.
○ Uses Merkle Trees (more info later)
● Verifiers check hash of the data compared to the blockchain transaction, then
verifies issuer & revocation status.
Technical Information
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9. 637ec732fa4b7b56f4c15a6a126
80519a17a9e9eade09f5b424a4
8eb0e6f5ad0
Blockchain Anchoring - Hashing
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Minimized Example

10. Blockchain TransactionCertificate
Transaction ID: d75b7...82f8
Blockchain Anchoring - Issuing
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11. Blockchain TransactionCertificate
Transaction ID: d75b7...82f8
Blockchain Anchoring - Verifying
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12. Certificate
Issuer
Revocation List
Blockchain Anchoring - Status Check

13. ● Created with the object of being blockchain agnostic
● First Bitcoin, then Ethereum.
● Has implementations in Hyperledger
● Blockchain ”connectors” in Open Source
○ Trivial to add more, depends on difficulty of developing for a given blockchain.
Blockchain Agnostic
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14. ● Merkle Tree mechanism also
used to verify transactions in
a blockchain.
● Single blockchain transaction
per issuance does not scale.
● Certificates hashed together
in a tree, resulting root hash
on the blockchain.
Scaling through Merkle Trees
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15. ● Blockcerts meant to be shared with verifiers
● Whole Blockcert is needed to verify
● Should not put more info than necessary
○ Example: Home Address in a Graduation Certificate
● Zero Knowledge Proofs can help mitigate PII, but not currently supported in
BlockcertsV2. More info later.
What data is safe to put in a Blockcerts?
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16. ● Currently supports HTML throughout the blockcerts
ecosystem.
● HTML is rendered when viewing a Blockcert in the
mobile app or through our frontend verifier
components.
● Harmful HTML is stripped from view.
● Currently not standardized in Blockcerts, plans for it
(and additional display types) for V3.
Verifiable Displays
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17. ● Part of verification when Issuer is checked.
● Many reasons for revocations
○ Accidental
○ Fraud,
○ Etc.
● Revocation URL with a list of certificate ID’s
and revocation reasons.
● Expirations supported without needing to do a
revocation.
● Will get uplifted in V3 along with Issuer URLs.
Revocations
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18. What companies are building a solutions around
Blockcerts?
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19. Use Cases
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20. www.zeemaps.com/blockcerts
Blockcerts Map

21. Blockcerts allows individuals to own their own credentials and share them in a
way that allows verifiers to prove that the certificates are valid, have not been
tampered with, existed at a specific time, and were issued by correct issuer.
Pros Cons
● Open Source / Open Standard
● Recipient ownership & portable
● Existed at a specific point in time
● Vendor-independent verification
● Verifiable display
● Blockchain agnostic
● Scalable with Merkle Proofs
● Revocable
● Interoperable Standards (JSON-LD, OB,
VC’s, DIDs)
● Entire certificate data is needed to verify
○ no Zero-Knowledge Proofs yet
● Requires a blockchain transaction to issue a
batch (costs for public blockchains).
● Some certralized points of failures around
issuer/revocation URLs
○ mitigated w/ DIDs in V3
Why Blockcerts?
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22. ● Version 3.0
○ Big focus on VC’s & DID’s
○ Coming out with a completed draft soon, seeking community feedback
● Learning Machine won a grant to align Blockcerts to the Verifiable Credentials
Standard & Decentralized Identifiers.
● Issuing and verification across additional blockchains, beyond Bitcoin and
Ethereum
Roadmap / Contributing
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23. A verifiable credential is a tamper-evident credential that has authorship that can
be cryptographically verified. Verifiable credentials can be used to build verifiable
presentations, which can also be cryptographically verified. The claims in a
credential can be about different subjects.
https://w3c.github.io/vc-data-model/
Verifiable Credentials
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24. Decentralized Identifiers (DIDs) are a new type of identifier for verifiable,
decentralized digital identity. These new identifiers are designed to enable the
controller of a DID to prove control over it and to be implemented independently of
any centralized registry, identity provider, or certificate authority. DIDs are URLs
that relate a DID subject to means for trustable interactions with that subject.
https://w3c-ccg.github.io/did-spec/
did:example:123456789abcdefghi
Decentralized Identifiers
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25. Anthony Ronning - @cycryptr
Blockcerts Dev and Backend
Engineer at Learning Machine
Daniel Paramo - @danparamov
Co-Founder of swys, Advisor at
Xertify and Founder of
echoisolutions
Thank you!
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