| Internet-Draft | Channel Bindings for TLS 1.3 | June 2020 |
| Whited | Expires 13 December 2020 | [Page] |
This document defines a channel binding type, tls-exporter, that is compatible with TLS 1.3 [RFC8446] in accordance with On Channel Binding [RFC5056].¶
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After problems were found with the channel binding types defined in [RFC5929] they were not defined for TLS 1.3 (see [RFC8446] section 7.5). To facilitate channel binding with TLS 1.3, a new channel binding type is needed.¶
Throughout this document the acronym "EKM" is used to refer to Exported Keying Material as defined in [RFC5705].¶
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.¶
IANA will register the 'tls-exporter' channel binding type to match the description below.¶
Description: The EKM value obtained from the current TLS connection.¶
The EKM is obtained using the keying material exporters for TLS as defined in [RFC5705] by supplying the following inputs:¶
When TLS renegotiation is enabled channel binding using the "tls-exporter" type is not define and MUST NOT be supported.¶
While it is possible to use this channel binding mechanism with TLS versions below 1.3, extra precaution must be taken to ensure that the chosen cipher suites always result in unique master secrets. For more information see the Security Considerations section of [RFC5705].¶
The Security Considerations sections of [RFC5056], [RFC5705], and [RFC8446] apply to this document.¶
This document adds the following registration in the "Channel-Binding Types" registry:¶