The Web Public Key Infrastructure (PKI) is the set of systems, policies, and procedures used to protect the confidentiality, integrity, and authenticity of communications between Web browsers and Web content servers. The Web PKI is used in conjunction with security protocols such as TLS/SSL and OCSP. More specifically, the Web PKI (as considered here) consists of the fields included in the certificates issued to Web content and application providers by Certification Authorities (CAs), the certificate status services provided by the Authorities to Web browsers and their users, and the TLS/SSL protocol stacks embedded in web servers and browsers. The Web PKI Operations (wpkops) working group will work to improve the consistency of Web security behavior. It will address the problems caused by the many hundreds of variations of the Web PKI currently in use: - For end-users (i.e. relying parties), there is no clear view of whether certificate "problems" remain once they see an indication of a "good" connection. For instance, in some browsers, a "good" indication is displayed when a "revoked" response has been received and "accepted" by the user, whereas other browsers refuse to display the contents under these circumstances. - Many certificate holders are unsure which browser versions will reject their certificate if certain certificate profiles are not met, such as a subject public key that does not satisfy a minimum key size, or a certificate policies extension that does not contain a particular standard policy identifier. - Certificate issuers (i.e., CAs) find it difficult to predict whether a certificate chain with certain characteristics will be accepted. For instance, some browsers include a nonce in their OCSP requests and expect one in the corresponding responses, not all servers include a nonce in their replies, and this means some certificate chains will validate while others won't. The working group's goal is to describe how the Web PKI "actually" works in the set of browsers and servers that are in common use today. To that end, the working group will document current and historic browser and server behavior. For each this will include: - The trust model on which it is based; - The contents and processing of fields and extensions; - The processing of the various revocation schemes; - How the TLS stack deals with PKI, including varying interpretations and implementation errors, as well as state changes visible to the user. - The state changes that are visible to and/or controlled by the user (to help predict the decisions that will be made the users and so determine the effectiveness of the Web PKI). - Identification of when Web PKI mechanisms are reused by other applications and implications of that reuse. Where appropriate, specific products and specific versions of those products will be identified, but recording the design details of the user interfaces of specific products is not necessary. Only server-authentication behavior encountered in more than 0.1 percent of connections made by desktop and mobile browsers is to be considered. While it is not intended to apply the threshold with any precision, it will be used to justify the inclusion or exclusion of a technique. A number of activities are outside the immedaiate scope of this working group, but might be considered in future re-chartering activity or included in the work of other working groups: - The working group will not work to describe how thw Web PKI "should work. - The working group will not examine the certification practices of certificate issuers. - The working group will not investigate applications (such as client authentication, document signing, code signing, and email) that often use the same trust anchors and certificate processing mechanisms as those used for Web server authentication. Given the urgency of the required developments and the scale of the task, it is agreed that adherence to the published milestones will take precedence over completeness of the results, without sacrificing technical correctness.