Architecture

• AML – Anti-Money Laundering

• KYC – Know Your Customer

• VC – Verifiable Credential

• ZKP – Zero-Knowledge Proof

Internal Components

Albus Protocol includes 3 layers: frontend, blockchain, and backend.

Frontend Layer

The frontend layer includes user interfaces that provide the following functionality for different user roles:

• End user:

  • Manages VCs.

  • Manage Compliance Certificates.

  • Manage due diligence (DD) requests and proofs.

• Business user:

  • Manage policies.

  • Assign and remove Trustees.

  • View Compliance Certificates of end users.

• AML Officer:

  • Define due diligence (DD) specifications.

  • Issue proofs of due diligence (DD) for compliant users.

• Trustee:

  • Store key shares for retained user data.

  • Provide key shares to verified authorised entities based on their disclosure requests.

• Authorised entity:

  • Submit disclosure requests to a predefined list of Trustees.

  • Use key shares of Trustees to reconstruct a key for decrypting retained user data.

Blockchain Layer

The blockchain layer includes the following data and smart contract entities:

• Encrypted VCs (NFT): W3C Verifiable Credentials stored in encrypted form as NFT and controlled by end users.

• Policy: a requirement or a set of requirements defined by a business user for end users who want to use its service.

• Circuit: a cryptographic circuit that generates a Zero-Knowledge Proof, which proves that an end user complies with a business user's policy without revealing the end user's personal data.

• Compliance Certificate: a Certificate issued by Albus to confirm that an end user complies with a business user's policy.

• DD requests: due diligence (DD) requests submitted by end users to an AML Officer.

• Disclosure request: requests for the disclosure of retained user data submitted by an authorised entity to a predefined list of Trustees.

For detailed definitions, please refer to the Glossary.

Backend Layer

The backend layer includes the following methods that support operation of Albus Protocol:

• VC methods.

• VP methods.

• ZK Proof methods.

• Certificate methods.

• Policy methods.

• Circuit methods.

For details, please refer to the Integration and CLI sections.

External Components

Albus interacts with the following external entities:

• End user: an individual or an entity that obtains digital credentials by undergoing verification with an Issuer, and uses them to obtain Compliance Certificates in order to prove compliance with a business user's policy.

• Business user: a Web3 business that sets policies incorporating one or several requirements to verify that its end users comply with them.

• AML Officer: a type of Issuer that conducts due diligence checks and issues proofs of due diligence (DD) for compliant users. It can be an in-house employee of a Web3 business or some other trusted entity.

• Issuer: a trusted third-party entity that verifies end users and, in case of successful verification, issues Verifiable Credentials for them (e.g., KYC provider).

• Issuer node: a Node.js node that issues Verifiable Credentials for users in case an Issuer cannot provide user data (claims) in the W3C Verifiable Credential format. It runs Adapters that fetch user data from an Issuer and convert it to the W3C Verifiable Credential format. Each Adapter is dedicated to a specific Issuer.

• Trustee: a trusted compliance partner that holds a share of the key required to decrypt retained user data in case it is required by an authorised entity with a legitimate request.

• Authorised entity: an individual or an entity authorised to access retained user data for a legitimate purpose (e.g., conduct an investigation or an audit).

For detailed definitions, please refer to the Glossary.