Given that you are shipping across the internet I would encrypt my backup too. that you cannot do with SQL Server built-in stuff. Either get third party tool (which may not be functional on AWS instance) or use 7zip et al to handle compression/encryption and build a simple process to handle decryption/compression in cloud (should be doable, but not haven't tried it).
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service