privacy pass

This document specifies the Privacy Pass architecture and requirements for its constituent protocols used for authorization based on privacy-preserving authentication mechanisms. It describes the conceptual model of Privacy Pass and its protocols, its security and privacy goals, practical deployment models, and recommendations for each deployment model, to help ensure that the desired security and privacy goals are fulfilled.

This document defines an HTTP authentication scheme for Privacy Pass, a privacy-preserving authentication mechanism used for authorization. The authentication scheme specified in this document can be used by Clients to redeem Privacy Pass tokens with an Origin. It can also be used by Origins to challenge Clients to present Privacy Pass tokens.

This document specifies two variants of the two-message issuance protocol for Privacy Pass tokens: one that produces tokens that are privately verifiable using the Issuer Private Key and one that produces tokens that are publicly verifiable using the Issuer Public Key. Instances of "issuance protocol" and "issuance protocols" in the text of this document are used interchangeably to refer to the two variants of the Privacy Pass issuance protocol.