A group of privacy advocates, publishers, and privacy software companies have proposed an “unofficial” specification for how consumers might transmit, and how companies might receive, a global privacy opt-out signal that indicates an intention for information not to be sold. They refer to their specification as the Global Privacy Control header, “GPC header,” or “GPC signal.”
Browsers, plug-ins, or other devices that decide to incorporate the GPC header would ask consumers if they would like to broadcast a preference that information that is collected about them online not be sold. If a consumer selected such an option, the consumer’s internet browser would broadcast the following HTML header every time the consumer visited a webpage on the internet:
Sec-GPC-field-name = “Sec-GPC”
Sec-GPC-field-value = “1”
The “field value” of “1” is intended to convey that the consumer does not want their information sold or shared.