List objects in an S3 bucket with no server-side encryption

unencrypted_objects.rb

require 'aws-sdk-s3'

client = Aws::S3::Client.new(region: 'us-west-2')

bucket = 'bucket1'

resp = client.list_objects(bucket: bucket)
resp.contents.each do |object|
  metadata = client.head_object(bucket: bucket, key: object.key)
  puts object.key unless metadata.server_side_encryption
end