I m not sure what your main goal is or if you have read about the services you ask about. But I will try to explain it as far as I ve understood AWS and your choices:
- S3 is a STORAGE (with buckets and objects, a sort of folder structure with meta access)
- EBS is a VOLUME (these are attached to an EC2 instance as extra drive you can access as a local harddrive)
- CloudFront is a WEB-CACHE (you select which datacenter you want them in, and then you point at a S3 bucket and Amazon will replicate the content for you)
So we only need to figure out what you mean by "securely" as there are two options as I see it:
You can protect buckets in the S3 or make access levels with accounts, for "administrator access" only and PUBLIC READABLE...
You can store the data in a EBS volume and keep them there, then they are very secure and NOT public, but shareable (I believe) among the servers (I ve planned to check out this myself within the next week)
You cannot protect "cloudfront" data as it s controlled by the Bucket permissions from S3...
Hope you can use this a little. I ve not stated anything regarding SPEED nor COST, thats for you to benchmark/test with your data requirements. :o)