Resource integrity for HTTP. Rather than having HTTP redirect to HTTPS with a content-free dummy page in the request body, the body of the 301 response is the same content being served over HTTPS, but the HTTP request has an additional Integrity header that allows: 1. verifying that the payload is not forged (signed by the same party that has the TLS certificate) 2. a subsequent, ETag-based conditional request to the HTTPS endpoint (Only for perambulatory browsing—not auth'd.)