The Data Issuer only needs to follow this step for integration with the zkPass Service:

• Providing REST API for user data retrieval

Sample Implementation

Sample codes for the Data Issuer implementation follow. Each step is explained in detail in the subsections. The code is also available on the zkpass-sdk repo, as shown here:

The Data Issuer is required to expose a REST API that facilitates secure user data token retrieval. The API should be designed to authenticate the user robustly, ensuring that only the legitimate owner can access the data. The zkPass SDK does not dictate the precise authentication mechanisms, API semantics, or response formats, providing developers the flexibility to implement an approach best suited to their application's architecture.

The Data Issuer needs to make sure the user data is in JSON encoding. The DVR app architecture does not dictate the schema or structure of the user data, however, JSON encoding is required.

By conforming to these guidelines, Data Issuers contribute to the robustness and security of the DVR app infrastructure, ensuring an optimized and secure experience for all users involved.

Dvr Module Client Integration

Signing the User Data

As the authority provisioning sensitive user data, the Data Issuer plays a critical role in the DVR ecosystem. To ensure the authenticity of the user data, the Data Issuer must sign this sensitive information into a JWS (JSON Web Signature) token. The signing of the user data by the Data Issuer is illustrated by part of the DVR/zkPass call sequence, which is highlighted in red below:

The Dvr module client SDK library provides a specialized utility method for this purpose: callDvrGenerateUserDataToken. How to digitally sign the user data using the Dvr module client SDK library is illustrated by the code snippet below.

// Step 1: Instantiate DvrModuleClient
const dvrModuleClient = new DvrModuleClient({
      baseUrl: SERVICE_URL,
      apiKey: API_KEY,
      secretApiKey: API_SECRET,
    });
//
// Step 2: Call the DVR module client's callDvrGenerateUserDataToken
//         This is to digitally-sign the user data.
const userDataToken = dvrModuleClient.callDvrGenerateUserDataToken(
      signingKey,
      JSON.stringify(data),
      verifyingKey
    );

Parameters passed to callDvrGenerateUserDataToken:

• signingKey This is the signing private key owned by the Data Issuer.

• JSON.stringify(data) This is a stringified JSON user data.

• verifyingKey This is a key to validate user data token.