From http://docs.aws.amazon.com/redshift/latest/dg/c_loading-encrypted-files.html Copy to Redshift using a specified encryption key
copy customer from 's3://mybucket/encrypted/customer'
credentials 'aws_access_key_id=<access-key-id>;aws_secret_access_key=<secret-access-key>;master_symmetric_key=<master_key>'
delimiter '|' encrypted;