I would like to create a signed URL for images in a directory inside a Google Cloud Storage bucket in Node.js. Looking at the SDK for Google Cloud Storage in Node.js you can easily create a signed url for a specific file. However it doesn’t look like you can create a signed url with a prefix.

Looking at the Cloud CDN docs, it is however possible to create a signed URL with a prefix. This approach uses keys to generate the signed URL.

However, I’m using ADC to authenticate my service already for the Cloud Storage SDK. I would like to continue using ADC and avoid creating keys and their corresponding service accounts.

Is there any way I can get a signing key from the Cloud Storage SDK to use instead of having to generate and manage different signed request keys for my backend?