Looking for a secure place to store scanned tax forms

I am looking for something like Cloudinary that I can store w-9s that would be filled out by contractors. They get scanned and need to be stored for access at the end of the year. Do you think cloudinary would be secure enough for that or do you know of something that I could use that would encrypt them?

I am pretty sure that AWS S3 has an option to store files with encryption.

Thanks. I also found that cloudinary has a Private feature for the pictures.