Draft: draft-ietf-tls-subcerts

Commentary: Fixed in
Paragraph (version A):
To reduce the dependency on external CAs, this document proposes a
limited delegation mechanism that allows a TLS peer to issue its own
credentials within the scope of a certificate issued by an external
CA.  These credentials only enable the recipient of the delegation to
speak for names that the CA has authorized.
Paragraph (version B):
To reduce the dependency on external CAs, this document proposes a
limited delegation mechanism that allows a TLS peer to issue its own
credentials within the scope of a certificate issued by an external
CA.  These credentials only enable the recipient of the delegation to
speak for names that the CA has authorized.  Furthermore, this
mechanism allows the server to use modern signature algorithms such
as Ed25519 RFC8032 even if their CA does not support them.
Paragraph (version B):
RFC EDITOR PLEASE DELETE THIS SECTION.
Paragraph (version A):
Each delegated credential is bound to a specific signature
algorithm that may be used to sign the TLS handshake (RFC8446
section 4.2.3).  This prevents them from being used with other,
perhaps unintended signature algorithms.
Paragraph (version B):
Each delegated credential is bound to a specific signature
algorithm for use use in the TLS handshake (RFC8446 section
unintended signature algorithms.
Paragraph (version A):
Use of short-lived certificates with automated certificate issuance,
e.g., with Automated Certificate Managment Environment (ACME)
RFC8555, reduces the risk of key compromise, but has several
limitations.  Specifically, it introduces an operationally-critical
dependency on an external party.  It also limits the types of
algorithms supported for TLS authentication to those the CA is
willing to issue a certificate for.  Nonetheless, existing automated
issuance APIs like ACME may be useful for provisioning delegated
credentials.
Paragraph (version B):
Use of short-lived certificates with automated certificate issuance,
e.g., with Automated Certificate Management Environment (ACME)
RFC8555, reduces the risk of key compromise, but has several
limitations.  Specifically, it introduces an operationally-critical
dependency on an external party (the CA).  It also limits the types
of algorithms supported for TLS authentication to those the CA is
willing to issue a certificate for.  Nonetheless, existing automated
issuance APIs like ACME may be useful for provisioning delegated
credentials.
Paragraph (version A):
Time in seconds relative to the beginning of the delegation
certificate's notBefore value after which the delegated credential
is no longer valid.  This MUST NOT exceed 7 days.
Paragraph (version B):
Time in seconds relative to the beginning of the delegation
certificate's notBefore value after which the delegated credential
is no longer valid.  Endpoints will reject delegate credentials
with valid_times exceeding 7 days (as described in client-and-
server-behavior).
Paragraph (version A):
Verify that the credential's remaining validity time is no more
than the maximum validity period.  This is done by asserting that
the current time is no more than the delegation certificate's
notBefore value plus DelegatedCredential.cred.valid_time plus the
maximum validity period.
Paragraph (version B):
Validate that DelegatedCredential.cred.valid_time is no more than
7 days.
Paragraph (version B):
Verify that the delegated credential's remaining validity time is
no more than the maximum validity period.  This is done by
asserting that the current time is no more than the delegation
certificate's notBefore value plus
DelegatedCredential.cred.valid_time plus the maximum validity
period.
Paragraph (version A):
This document also defines an ASN.1 module for the DelegationUsage
certificate extension in module.  IANA is requested to register an
Object Identfier (OID) for the ASN.1 in "SMI Security for PKIX Module
Identifier" arc.  An OID for the DelegationUsage certificate
extension is not needed as it is already assigned to the extension
from Cloudflare's IANA Private Enterprise Number (PEN) arc.
Paragraph (version B):
This document also defines an ASN.1 module for the DelegationUsage
certificate extension in module.  IANA has registered value 95 for
"id-mod-delegated-credential-extn" in the "SMI Security for PKIX
Module Identifier" (1.3.5.1.5.5.7.0) registry.  An OID for the
DelegationUsage certificate extension is not needed as it is already
assigned to the extension from Cloudflare's IANA Private Enterprise
Number (PEN) arc.