Use of VAPID in JMAP WebPush

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Table of Contents

1. Introduction

JMAP [RFC8620] specifies how clients can subscribe to events using a protocol that is compatible to WebPush [RFC8030]. Some push services require that the application server authenticates all push messages using the Voluntary Application Server Identification protocol [RFC8292]. To faciliate that the client (or user agent in WebPush terminology) needs the VAPID public key of the application server to pass it along to the push service when retrieving a new endpoint.¶

2. Conventions Used in This Document

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. These words may also appear in this document in lower case as plain English words, absent their normative meanings.¶

3. Discovering Support for VAPID

The JMAP capabilities object is returned as part of the standard JMAP session object (see Section 2 of [RFC8620]). Servers supporting this specification MUST add a property called "urn:ietf:params:jmap:webpush-vapid" to the capabilities object. The value of this property is an object that MUST contain the following information:¶

• applicationServerKey: "String"¶

  The P-256 public key that the push service will use to authenticate the application server, encoded in URL-safe base64 representation as defined in [RFC4648].¶

4. Issuing Push Notifications

Every time the server sends a push message to a PushSubscription URL it MUST authenticate that POST request using the protocol outlined in [RFC8292]. This includes both StateChange events and PushVerification notifications.¶

5. Security Considerations

The security considerations for JMAP ([RFC8620], especially Section 8.6 and Section 8.7 of that document), WebPush ([RFC8030]) and VAPID ([RFC8292]) apply to this document.¶

6. IANA Considerations

7. Normative References

[RFC8620]

Jenkins, N. and C. Newman, "The JSON Meta Application Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July 2019, <https://www.rfc-editor.org/info/rfc8620>.

[RFC8030]

Thomson, M., Damaggio, E., and B. Raymor, Ed., "Generic Event Delivery Using HTTP Push", RFC 8030, DOI 10.17487/RFC8030, December 2016, <https://www.rfc-editor.org/info/rfc8030>.

[RFC8292]

Thomson, M. and P. Beverloo, "Voluntary Application Server Identification (VAPID) for Web Push", RFC 8292, DOI 10.17487/RFC8292, November 2017, <https://www.rfc-editor.org/info/rfc8292>.

[RFC2119]

Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.

[RFC8174]

Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.

[RFC4648]

Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, <https://www.rfc-editor.org/info/rfc4648>.

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