Implementation of Synacor authentication into AMP. The plugin can be implemented by providing a synacor object in the player config:

var config = {
  plugins: {
    synacor: {
      resources: [
          { src: "#{paths.plugins}synacor/Synacor.min.js", debug: "#{paths.plugins}synacor/Synacor.js", type: "text/javascript" }
      ],
      mvpd: {
          url: "//path_to_mvpd_endpoint",
          featured: [270, 268, 273],
      },
      passive: false,
      service: "xyz",
      partner: "eyJlbnZpcm9ubWVudCI6Im1hdiJ9",
      display: {
          method: "redirect",
          heigth: 100,
          width: 200
      },
      transform: false
    }
  }
};

  akamai.amp.AMP.create("#akamai-media-player", config, function (event) {
      amp = event.player;
      amp.addTransform(akamai.amp.TransformType.MEDIA, {
          transform: function (media) {
              return bounce()
                  .then(function (data) {
                      // Provides a base64 encoded authN
                      return amp.synacor.authenticate(data)
                  })
                  .then(function (identity) {
                      // Custom request 
                      return authz(identity.response)
                  })
                  .then(function (data) {
                      return amp.synacor.authorize(data)
                  })
                  .then(function (authorization) {
                      media.authorization = { key: "hdnea", token: authorization.securityToken }
                      return media
                  })
                  .catch(function () {
                      amp.synacor.chooser()
                  })
          },
          priority: 1
      })
  });