Use environment variables with sensible information in Docker Hub autobuild

Docker Hub has a section in the "Build configurations" section to specify build environment variables:

The problem is that the value of the variable appears in clear text, which makes this mechanism unsuitable for variables holding sensitive information (e.g. passwords).

I was thinking in something similar to the secrets mechanism in GitHub which allow to define variables which value is seen only one time (in the moment of creating them) but can be latter used in GitHub Actions as many times as you want.

Is there a way to define build variables in Docker Hub without showing the value in the interface? Or any other suitable workaround?

Given that it seems there is no solution to this in the dockerhub space, I have opted for the workaround of solving it with a GitAction. Something like this:

name: Publish Docker image (master)

on:
  push:
    branches:
      - master      

jobs:
  build-and-push:
    runs-on: ubuntu-latest

    steps:
    - name: Checkout code
      uses: actions/checkout@v3

    - name: Set up Docker Buildx
      uses: docker/setup-buildx-action@v2

    - name: Log in to Docker Hub
      uses: docker/login-action@v2
      with:
        username: ${{ secrets.DOCKERHUB_TEF_USERNAME }}
        password: ${{ secrets.DOCKERHUB_TEF_TOKEN }}

    - name: Build Docker image
      run: docker build -t telefonicaiot/fiware-orion:latest --build-arg GIT_REV_ORION=master --build-arg REPO_ACCESS_TOKEN=${{ secrets.REPO_ACCESS_TOKEN }} --no-cache -f docker/Dockerfile .

    - name: Push Docker image
      run: docker push telefonicaiot/fiware-orion:latest

Where secrets.REPO_ACCESS_TOKEN holds the secret that I cannot use at dockerhub.