Uploads a public key to CloudFront that you can use with <a href="https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/PrivateContent.html">signed URLs and signed cookies</a>, or with <a href="https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/field-level-encryption.html">field-level encryption</a>.