http://www.rfc-editor.org/rfc/rfc2817.txt
RFC 2817: Upgrading to TLS Within HTTP/1.1, R. Khare, S. Lawrence2000-05-01T23:00:00-00:00This memo explains how to use the Upgrade mechanism in HTTP/1.1 to initiate Transport Layer Security (TLS) over an existing TCP connection. [STANDARDS-TRACK]