Storage Service

The storage service directory contains an Express REST API that provides endpoints to encrypt and store Verifiable Credentials and documents.

Overview

The service offers the following functionality:

• Hash Computation: Computes the SHA-256 hash of a given document to ensure data integrity.
• Encryption: Encrypts the document using AES-256-GCM for enhanced security.
• Storage: Stores the encrypted document using the specified storage adapter (local file system or Google Cloud Storage).
• Data Retrieval: Upon successful storage, the service returns:
  • The hash of the original document.
  • A decryption key for the encrypted document (if applicable).
  • The URI of the stored encrypted document.

Prerequisites

• Node.js (v18.18.0)
• Yarn (>= 1.22.21)

Environment Variables

An example environment file .env.example is provided in the storage service directory. Copy and rename it to .env, then modify the variables as required. The default values should be sufficient for local development.

Usage

# Install dependencies
yarn install

# Build the app
yarn build

# Run the app and watch for changes
yarn dev

# Start the server once built
yarn start

# Run linter
yarn lint

# Run tests
yarn test

Configuration

Configure the storage service using the following environment variables:

• STORAGE_TYPE: The type of storage to use (local or gcp).
• LOCAL_DIRECTORY: The directory for local storage (default: uploads in the current directory).
• GOOGLE_APPLICATION_CREDENTIALS: The path to the GCP service account file (if using GCP).

Storage Types

Local Storage

For development purposes, use the local storage service, which stores files in the local file system.

Example:

# Set the storage type to local
export STORAGE_TYPE=local

# Run the app
yarn dev

Google Cloud Storage

For production environments, use Google Cloud Storage to store files in a GCP bucket.

Example:

# Set the storage type to gcp
export STORAGE_TYPE=gcp

# Set the path to the GCP service account file
export GOOGLE_APPLICATION_CREDENTIALS=/path/to/service-account-file.json

# Build the app
yarn build

# Run the app
yarn start

Cryptography

The cryptography service uses the following algorithms:

• Hash Algorithm: SHA-256
• Encryption Algorithm: AES-256-GCM

Endpoints

Store Credential

• URL: /v1/credentials

• Method: POST

• Request Body:

  {
      "bucket": "verifiable-credentials",
      "data": {
          "field1": "value1",
          "field2": "value2"
      },
      "id": "123e4567-e89b-12d3-a456-426614174000" // optional
  }

• Response:

  {
      "uri": "http://localhost:3333/v1/verifiable-credentials/123e4567-e89b-12d3-a456-426614174000.json",
      "hash": "computed-hash",
      "key": "encryption-key"
  }

Store Document

• URL: /v1/documents

• Method: POST

• Request Body:

  {
      "bucket": "verifiable-credentials",
      "data": {
          "document": "content"
      },
      "id": "123e4567-e89b-12d3-a456-426614174000" // optional
  }

• Response:

  {
      "uri": "http://localhost:3333/v1/verifiable-credentials/123e4567-e89b-12d3-a456-426614174000.json",
      "hash": "computed-hash"
  }

Docker

To run the storage service using Docker:

# Build the image
docker build -t storage-service:latest .

# Start the container using local storage
docker run -d --env-file .env -p 3333:3333 \
storage-service:latest

# Start the container using Google Cloud Storage
docker run -d --env-file .env -p 3333:3333 \
-e STORAGE_TYPE=gcp \
-v path/to/local/gcp/service-account-file.json:/tmp/service-account-file.json \
storage-service:latest