Best way to install private/paid plugins with Composer?

bedrock
11

think I resolved it using zip files:

{
  "name": "TTSS",
  "homepage": "http://satis.ttss.ch",

  "repositories": [
    {
      "type": "package",
      "package": {
        "name": "themeco/x-shortcodes",
        "description": "Includes all shortcode functionality for X",
        "keywords": ["themeco","x-shortcodes"],
        "license": "LGPL-3.0+",
        "authors": [
          {
            "name":"Themeco",
            "homepage":"http://theme.co"
          }
        ],
        "version": "2.3.3",
        "dist": {
          "url": "http://satis.ttss.ch/files/x-shortcodes.zip",
          "type": "zip"
        },
        "type": "wordpress-plugin",
        "require": {
            "php": ">=5.3.2",
            "composer/installers": "*"
        }
      }
    }
  ],
  "require-all": true
}