rfc9578v3.txt		rfc9578.txt
	Internet Engineering Task Force (IETF) S. Celi		Internet Engineering Task Force (IETF) S. Celi
	Request for Comments: 9578 Brave Software		Request for Comments: 9578 Brave Software
	Category: Standards Track A. Davidson		Category: Standards Track A. Davidson
	ISSN: 2070-1721 NOVA LINCS, Universidade NOVA de Lisboa		ISSN: 2070-1721 NOVA LINCS, Universidade NOVA de Lisboa
	S. Valdez		S. Valdez
	Google LLC		Google LLC
	C. A. Wood		C. A. Wood
	Cloudflare		Cloudflare
	May 2024		June 2024
	Privacy Pass Issuance Protocols		Privacy Pass Issuance Protocols
	Abstract		Abstract
	This document specifies two variants of the two-message issuance		This document specifies two variants of the two-message issuance
	protocol for Privacy Pass tokens: one that produces tokens that are		protocol for Privacy Pass tokens: one that produces tokens that are
	privately verifiable using the Issuer Private Key and one that		privately verifiable using the Issuer Private Key and one that
	produces tokens that are publicly verifiable using the Issuer Public		produces tokens that are publicly verifiable using the Issuer Public
	Key. Instances of "issuance protocol" and "issuance protocols" in		Key. Instances of "issuance protocol" and "issuance protocols" in
	skipping to change at line 725 ¶		skipping to change at line 725 ¶
	Content-Length: <Length of TokenResponse>		Content-Length: <Length of TokenResponse>
	<Bytes containing the TokenResponse>		<Bytes containing the TokenResponse>
	6.3. Finalization		6.3. Finalization
	Upon receipt, the Client handles the response and, if successful,		Upon receipt, the Client handles the response and, if successful,
	processes the content as follows:		processes the content as follows:
	authenticator =		authenticator =
	Finalize(pkI, nonce, blind_sig, blind_inv)		Finalize(pkI, PrepareIdentity(token_input), blind_sig, blind_inv)
	The Finalize function is defined in Section 4.4 of [BLINDRSA]. If		The Finalize function is defined in Section 4.4 of [BLINDRSA]. If
	this succeeds, the Client then constructs a token as described in		this succeeds, the Client then constructs a token as described in
	[AUTHSCHEME] as follows:		[AUTHSCHEME] as follows:
	struct {		struct {
	uint16_t token_type = 0x0002; /* Type Blind RSA (2048-bit) */		uint16_t token_type = 0x0002; /* Type Blind RSA (2048-bit) */
	uint8_t nonce[32];		uint8_t nonce[32];
	uint8_t challenge_digest[32];		uint8_t challenge_digest[32];
	uint8_t token_key_id[32];		uint8_t token_key_id[32];
	skipping to change at line 1032 ¶		skipping to change at line 1032 ¶
	Author: See the Authors' Addresses section of RFC 9578.		Author: See the Authors' Addresses section of RFC 9578.
	Change controller: IETF		Change controller: IETF
	9. References		9. References
	9.1. Normative References		9.1. Normative References
	[ARCHITECTURE]		[ARCHITECTURE]
	Davidson, A., Iyengar, J., and C. A. Wood, "The Privacy		Davidson, A., Iyengar, J., and C. A. Wood, "The Privacy
	Pass Architecture", RFC 9576, DOI 10.17487/RFC9576, May		Pass Architecture", RFC 9576, DOI 10.17487/RFC9576, June
	2024, <https://www.rfc-editor.org/info/rfc9576>.		2024, <https://www.rfc-editor.org/info/rfc9576>.
	[AUTHSCHEME]		[AUTHSCHEME]
	Pauly, T., Valdez, S., and C. A. Wood, "The Privacy Pass		Pauly, T., Valdez, S., and C. A. Wood, "The Privacy Pass
	HTTP Authentication Scheme", RFC 9577,		HTTP Authentication Scheme", RFC 9577,
	DOI 10.17487/RFC9577, May 2024,		DOI 10.17487/RFC9577, June 2024,
	<https://www.rfc-editor.org/info/rfc9577>.		<https://www.rfc-editor.org/info/rfc9577>.
	[BLINDRSA] Denis, F., Jacobs, F., and C. A. Wood, "RSA Blind		[BLINDRSA] Denis, F., Jacobs, F., and C. A. Wood, "RSA Blind
	Signatures", RFC 9474, DOI 10.17487/RFC9474, October 2023,		Signatures", RFC 9474, DOI 10.17487/RFC9474, October 2023,
	<https://www.rfc-editor.org/info/rfc9474>.		<https://www.rfc-editor.org/info/rfc9474>.
	[HTTP] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,		[HTTP] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
	Ed., "HTTP Semantics", STD 97, RFC 9110,		Ed., "HTTP Semantics", STD 97, RFC 9110,
	DOI 10.17487/RFC9110, June 2022,		DOI 10.17487/RFC9110, June 2022,
	<https://www.rfc-editor.org/info/rfc9110>.		<https://www.rfc-editor.org/info/rfc9110>.
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