how do I allow ONLY my EC2 instances to access a specific S3 bucket

Question

I'm using S3 to host files that will be used to bootstrap my instances, but having a hard time setting up S3 so that only my instances will have read access, as I don't want anyone else to be able to download the config packages and scripts.

Answer 1

figured out my problem, with the presigned urls,

in the end it was just a simple "", I was executing

~# runurl http://it-test.s3.amazonaws.com/setup.sh?AWSAccessKeyId=XXXXXXXXXXXXXXXXXX&Expires=1275294519&Signature=E3bC34565jj3456VkewXF2Sed3s%3D

and it should have been

~# runurl "http://it-test.s3.amazonaws.com/setup.sh?AWSAccessKeyId=XXXXXXXXXXXXXXXXXX&Expires=1275294519&Signature=E3bC34565jj3456VkewXF2Sed3s%3D"

otherwise anything after the & is not included.