P3P解决cookie跨域

P3P是什么

P3P（Platform for Privacy Preferences）是W3C公布的一项隐私保护推荐标准，以为用户提供隐私保护。   P3P标准的构想是：Web 站点的隐私策略应该告之访问者该站点所收集的信息类型、信息将提供给哪些人、信息将被保留多少时间及其使用信息的方式，如站点应做诸如 “本网站将监测您所访问的页面以提高站点的使用率”或“本网站将尽可能为您提供更合适的广告”等申明。访问支持P3P网站的用户有权查看站点隐私报告，然 后决定是否接受cookie 或是否使用该网站。

利用P3P实现跨域

有别于JS跨域、IFRAME跨域等的常用处理办法，通过发送P3P头信息而实现的跨域。

PHP 使用P3P协议

header(‘P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR"‘);

JS 使用P3P协议

xmlhttp.setRequestHeader( "P3P" , ‘CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR"‘ );

ASP.NET 使用P3P协议

HttpContext.Current.Response.AddHeader("p3p", "CP=\"IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT\"")

JSP 使用P3P协议

response.addHeader("P3P", "CP=IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT");

策略说明

(http://www.w3.org/2002/04/P3Pv1-header.html)

compact-policy-field         =   `CP="` compact-policy `"`

compact-policy                = compact-token *(" " compact-token)

compact-token                = compact-access           |

compact-disputes         |

compact-remedies         |

compact-non-identifiable |

compact-purpose          |

compact-recipient        |

compact-retention        |

compact-categories       |

compact-test

compact-access           = "NOI" | "ALL" | "CAO" | "IDC" | "OTI" | "NON"

compact-disputes            = "DSP"

compact-remedies          = "COR" | "MON" | "LAW"

compact-non-identifiable = "NID"

compact-purpose           = "CUR"        | "ADM" [creq] | "DEV" [creq] | "TAI" [creq] |

"PSA" [creq] | "PSD" [creq] | "IVA" [creq] | "IVD" [creq] |

"CON" [creq] | "HIS" [creq] | "TEL" [creq] | "OTP" [creq]

creq                              = "a" | "i" | "o"

compact-recipient        = "OUR" | "DEL" [creq] | "SAM" [creq] | "UNR" [creq] |

"PUB" [creq] | "OTR" [creq]

compact-retention          = "NOR" | "STP" | "LEG" | "BUS" | "IND"

compact-category           = "PHY" | "ONL" | "UNI" | "PUR" | "FIN" | "COM" |

"NAV" | "INT" | "DEM" | "CNT" | "STA" | "POL" |

"HEA" | "PRE" | "LOC" | "GOV" | "OTC"

compact-test                  = "TST"

简洁策略

常用的简洁策略的 P3P头为 -   P3P : CP=CAO PSA OUR

最简洁的写法是 P3P:CP=.

compact-access(访问):  CAO - contact-and-other  允许第三方cookie的读写)
compact-purpose(目的):  PSA -  pseudo-analysis .目的就是做身份验证、分析
compact-recipient(受体):  OUR - ours 声明使用相关信息的人是谁,ours 第三方自己

浏览器支持情况

P3P策略

 相关资料：http://www.w3.org/P3P/