This document discusses blockchain APIs for enterprises and Azure blockchain services. It introduces blockchain versions from simple ledgers to smart contracts to confidential computing. It also outlines common blockchain needs in enterprises like connecting to communication channels, signing and verifying digital assets, and integrating with line of business apps. The document then focuses on Azure blockchain services like the Azure Blockchain Workbench for creating blockchain solutions and the Azure Blockchain Development Kit. It provides examples of how digital signatures can be implemented and verified on a blockchain through hashing content and metadata and storing hashes on the blockchain.

1. BLOCKCHAIN APIS
FOR THE ENTERPRISE
StefanoTempesta

2. Blockchain for Enterprise
Blockchain 1.0
Simple Ledgers
Blockchain 2.0
Smart Contracts
Blockchain 3.0
Confidential Computing

3. Blockchain needs in the enterprise
Connection with communication channels
• Mobile apps, web, SMS, voice, bots, IoT devices, …
Sign and verify digital assets
• Proof of existence and authenticity, audit trail
Integration with Line of Business applications
• CRM, ERP, Payroll, ... / File, FTP, SQL, API, …

4. SUPPLY CHAIN

8. AZURE
BLOCKCHAIN

9. Azure BlockchainWorkbench
Create end-to-end blockchain solutions based on Smart Contracts
No-code web client to run blockchain workflows
Messaging API for integration
Off-chain storage
Identity and Key management with Azure AD and KeyVault

10. Azure Blockchain Development Kit
Built on Microsoft’s serverless technologies
Integrates blockchain with Microsoft and third-party SaaS
CONNECT
API and data platforms
IoT devices
Mobile and web clients
SMS and voice
Bots
INTEGRATE
Document and media
Smart Contracts
Legacy FTP, files, email
DEPLOY
Cross-platform
DevOps
Transactions

11. DIGITAL SIGNATURE

12. Digital Signature
1. Institutes issue and sign
documents.
2. Documents are stored on an
independent repository.
3. Content and metadata hash values
are stored on a blockchain.
4. The address of the transaction
represents the authenticity token. Authenticity
Token
Stores
Issues & Signs
Content &
Metadata
Hash
Smart
Contract
Address
1
2
3
4
IPFS

13. Azure Blockchain Integration
REST API
Authenticates to AAD
RegisteredApplication
ReturnsToken
Calls API
Returns Data
Sends Request Message
Initiates Provisioning in DB
Returns Provisioning Status
Service Bus
Blockchain
Ledger
AzureAD

14. Blockchain Integration Flow
1. Hash file’s content and metadata.
2. Initialize the request.
3. Send the message to Service Bus.
4. Messages in the bus are retrieved
by the blockchain ledger.

15. Blockchain SignatureVerification
1. Individuals share the authenticity
token with the verifying institute.
2. Institutes retrieve documents and
hash values.
3. Documents are verified by
comparing the hash values stored
on a blockchain with the newly
calculated one.
4. Matching hash values prove
existence and authenticity. Authenticity
Token
IPFS
1
2
4
3
Verified
Certificate
Retrieves
certificate
On-Chain
Content &
Metadata
Hash
Verifies

16. Digital Signature on Blockchain
• Can sign any digital asset
• Signature stored separately from the digital asset
• No dependency on central authority for verification
• No need to distribute the digital asset
• Allow for multiple verifications at once

17. In summary…
Azure Blockchain “as a Service” Azure BlockchainWorkbench
Power Platform + Azure IoT & Integration Platform

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