Draft: draft-ietf-tls-subcerts

Commentary: Updating x690 version to match  ( 2015 ) Expanding acronyms ( avoid genart ) removed " ! " from some refs ( unneded ) r / LURK / KEYLESS ( completes derference from earlier PR ) .
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These dependencies cause problems in practice.  Server operators
often want to create short-lived certificates for servers in low-
trust zones such as CDNs or remote data centers.  This allows server
operators to limit the exposure of keys in cases that they do not
realize a compromise has occurred.  The risk inherent in cross-
organizational transactions makes it operationally infeasible to rely
on an external CA for such short-lived credentials.  In OCSP stapling
(i.e., using the Certificate Status extension types ocsp RFC6066 or
ocsp_multi RFC6961), if an operator chooses to talk frequently to the
CA to obtain stapled responses, then failure to fetch an OCSP stapled
response results only in degraded performance.  On the other hand,
failure to fetch a potentially large number of short lived
certificates would result in the service not being available, which
creates greater operational risk.
Paragraph (version B):
These dependencies cause problems in practice.  Server operators
often want to create short-lived certificates for servers in low-
trust zones such as Content Delivery Network (CDNs) or remote data
centers.  This allows server operators to limit the exposure of keys
in cases that they do not realize a compromise has occurred.  The
risk inherent in cross-organizational transactions makes it
operationally infeasible to rely on an external CA for such short-
lived credentials.  In Online Certiicate Status Protocol (OCSP)
stapling (i.e., using the Certificate Status extension types ocsp
RFC6066 or ocsp_multi RFC6961), if an operator chooses to talk
frequently to the CA to obtain stapled responses, then failure to
fetch an OCSP stapled response results only in degraded performance.
On the other hand, failure to fetch a potentially large number of
short lived certificates would result in the service not being
available, which creates greater operational risk.
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A delegated credential is a digitally signed data structure with two
semantic fields: a validity interval and a public key (along with its
associated signature algorithm).  The signature on the credential
indicates a delegation from the certificate that is issued to the
peer.  The secret key used to sign a credential corresponds to the
public key of the peer's X.509 end-entity certificate.
Paragraph (version B):
A delegated credential is a digitally signed data structure with two
semantic fields: a validity interval and a public key (along with its
associated signature algorithm).  The signature on the credential
indicates a delegation from the certificate that is issued to the
peer.  The secret key used to sign a credential corresponds to the
public key of the peer's X.509 end-entity certificate RFC5280.
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These two mechanisms can be complementary.  A server could use
credentials for clients that support them, while using LURK to
support legacy clients.
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It is possible to address the short-lived certificate concerns above
by automating certificate issuance, e.g., with ACME RFC8555.  In
addition to requiring frequent operationally-critical interactions
with an external party, this makes the server operator dependent on
the CA's willingness to issue certificates with sufficiently short
lifetimes.  It also fails to address the issues with algorithm
support.  Nonetheless, existing automated issuance APIs like ACME may
be useful for provisioning credentials within an operator network.
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These two mechanisms can be complementary.  A server could use
credentials for clients that support them, while using KEYLESS to
support legacy clients.
Paragraph (version B):
It is possible to address the short-lived certificate concerns above
by automating certificate issuance, e.g., with Automated Certificate
Managmeent Encvironment (ACME) RFC8555.  In addition to requiring
frequent operationally-critical interactions with an external party,
this makes the server operator dependent on the CA's willingness to
issue certificates with sufficiently short lifetimes.  It also fails
to address the issues with algorithm support.  Nonetheless, existing
automated issuance APIs like ACME may be useful for provisioning
credentials within an operator network.
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This document defines the following extension code point.
Paragraph (version B):
This document defines the following TLS extension code point.