Watsen Networks

kent+ietf@watsen.net

Operations NETCONF Working Group This document defines two YANG modules: the first defines a minimal grouping for configuring an HTTP client, and the second defines a minimal grouping for configuring an HTTP server. It is intended that these groupings will be used to help define the configuration for simple HTTP-based protocols (not for complete web servers or browsers). Editorial Note (To be removed by RFC Editor) This draft contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed. No other RFC Editor instructions are specified elsewhere in this document. Artwork in this document contains shorthand references to drafts in progress. Please apply the following replacements (note: not all may be present):

• AAAA --> the assigned RFC value for draft-ietf-netconf-crypto-types
• DDDD --> the assigned RFC value for draft-ietf-netconf-tcp-client-server
• FFFF --> the assigned RFC value for draft-ietf-netconf-tls-client-server
• GGGG --> the assigned RFC value for this draft

Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement:

• 2022-12-12 --> the publication date of this draft

The "Relation to other RFCs" section contains the text "one or more YANG modules" and, later, "modules". This text is sourced from a file in a context where it is unknown how many modules a draft defines. The text is not wrong as is, but it may be improved by stating more directly how many modules are defined. The "Relation to other RFCs" section contains a self-reference to this draft, along with a corresponding Informative Reference in the Appendix. The following Appendix section is to be removed prior to publication:

• . Change Log

Introduction This document defines two YANG 1.1 modules: the first defines a minimal grouping for configuring an HTTP client, and the second defines a minimal grouping for configuring an HTTP server. It is intended that these groupings will be used to help define the configuration for simple HTTP-based protocols (not for complete web servers or browsers).

Relation to other RFCs This document presents one or more YANG modules that are part of a collection of RFCs that work together to, ultimately, enable the configuration of both the clients and servers of both the NETCONF and RESTCONF protocols. The normative dependency relationship between the various RFCs in this collection is presented in the below diagram. The labels in the diagram represent the primary purpose provided by each RFC. Hyperlinks to each RFC are provided below the diagram. Label to RFC Mapping

Label in Diagram	Originating RFC
crypto-types
truststore
keystore
tcp-client-server
ssh-client-server
tls-client-server
http-client-server
netconf-client-server
restconf-client-server

Specification Language 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 when, and only when, they appear in all capitals, as shown here.

Adherence to the NMDA This document is compliant with the Network Management Datastore Architecture (NMDA) . For instance, as described in and , trust anchors and keys installed during manufacturing are expected to appear in <operational>.

Conventions Various examples used in this document use a placeholder value for binary data that has been base64 encoded (e.g., "BASE64VALUE="). This placeholder value is used as real base64 encoded structures are often many lines long and hence distracting to the example being presented.

The "ietf-http-client" Module This section defines a YANG 1.1 module called "ietf-http-client". A high-level overview of the module is provided in . Examples illustrating the module's use are provided in Examples. The YANG module itself is defined in .

Data Model Overview This section provides an overview of the "ietf-http-client" module in terms of its features and groupings.

Features The following diagram lists all the "feature" statements defined in the "ietf-http-client" module: The diagram above uses syntax that is similar to but not defined in .

Groupings The "ietf-http-client" module defines the following "grouping" statements:

• http-client-identity-grouping
• http-client-grouping
• http-client-stack-grouping

Each of these groupings are presented in the following subsections.

The "http-client-identity-grouping" Grouping The following tree diagram illustrates the "http-client-identity-grouping" grouping: Comments:

• This grouping exists because it is used three times by the "http-client-grouping" discussed in .
• The "client-identity" node is a "presence" container so the mandatory descendant nodes do not imply that this node must be configured, as a client identity may be configured at protocol layers.
• The "basic" authentication scheme is the only scheme defined by this module, albeit it must be enabled via the "basic-auth" feature (see ).
• Other authentication schemes MAY be augmented in as needed by the application.

The "http-client-grouping" Grouping The following tree diagram illustrates the "http-client-grouping" grouping: Comments:

• The "http-client-grouping" defines the configuration for just "HTTP" part of a protocol stack. It does not, for instance, define any configuration for the "TCP" or "TLS" protocol layers (for that, see ).
• Beyond configuring the client's identity, via the "http-client-identity-grouping" grouping discussed in , this grouping defines support for HTTP-proxies, albeit it must be enabled via a "feature" statement.
• The "proxy-connect" node is a "presence" container so the mandatory descendant nodes do not imply that this node must be configured, assuming the server supports the "proxy-connect" feature.
• For the referenced grouping statement(s):
  • The "http-client-identity-grouping" grouping is discussed in .
  • The "tcp-client-grouping" grouping is discussed in .
  • The "tls-client-grouping" grouping is discussed in .

The "http-client-stack-grouping" Grouping The following tree diagram illustrates the "http-client-stack-grouping" grouping: Comments:

• The "http-client-stack-grouping" is a convenience grouping for downstream modules. It defines both the "HTTP" and "HTTPS" protocol stacks, with each option enabled by a "feature" statement for application control.
• For the referenced grouping statement(s):
  • The "tcp-client-grouping" grouping is discussed in .
  • The "tls-client-grouping" grouping is discussed in .
  • The "http-client-grouping" grouping is discussed in in this document.

Protocol-accessible Nodes The "ietf-http-client" module defines only "grouping" statements that are used by other modules to instantiate protocol-accessible nodes.

Example Usage This section presents two examples showing the http-client-grouping populated with some data. The following example illustrates an HTTP client connecting directly to an HTTP server. bob secret ]]> The following example illustrates the same client connecting through an HTTP proxy. This example is consistent with examples presented in and . bob secret corp-fw2.example.com 15 3 30 rsa-asymmetric-key ex-rsa-cert trusted-server-ca-certs trusted-server-ee-certs local-app-1 secret ]]>

YANG Module This YANG module has normative references to . <CODE BEGINS> file "ietf-http-client@2022-12-12.yang" Author: Kent Watsen "; description "This module defines reusable groupings for HTTP clients that can be used as a basis for specific HTTP client instances. Copyright (c) 2022 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC GGGG (https://www.rfc-editor.org/info/rfcGGGG); see the RFC itself for full legal notices. 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 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here."; revision 2022-12-12 { description "Initial version"; reference "RFC GGGG: YANG Groupings for HTTP Clients and HTTP Servers"; } // Features feature proxy-connect { description "Proxy connection configuration is configurable for HTTP clients on the server implementing this feature."; } feature basic-auth { description "The 'basic-auth' feature indicates that the client may be configured to use the 'basic' HTTP authentication scheme."; reference "RFC 7617: The 'Basic' HTTP Authentication Scheme"; } feature tcp-supported { description "Indicates that the server supports HTTP/TCP."; } feature tls-supported { description "Indicates that the server supports HTTP/TLS."; } // Groupings grouping http-client-identity-grouping { description "A grouping to provide HTTP credentials used by the client to authenticate itself to the HTTP server."; container client-identity { nacm:default-deny-write; presence "Indicates that a client identity has been configured. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "The identity the HTTP client should use when authenticating itself to the HTTP server."; choice auth-type { mandatory true; description "A choice amongst available authentication types."; case basic { container basic { if-feature "basic-auth"; leaf user-id { type string; mandatory true; description "The user-id for the authenticating client."; } uses ct:password-grouping { description "The password for the authenticating client."; } description "The 'basic' HTTP scheme credentials."; reference "RFC 7617: The 'Basic' HTTP Authentication Scheme"; } } } } } // grouping http-client-identity-grouping grouping http-client-grouping { description "A reusable grouping for configuring a HTTP client. This grouping is expected to be used in conjunction with other configurations providing, e.g., the hostname or IP address and port number the client initiates connections to. Note that this grouping uses fairly typical descendant node names such that a stack of 'uses' statements will have name conflicts. It is intended that the consuming data model will resolve the issue (e.g., by wrapping the 'uses' statement in a container called 'http-client-parameters'). This model purposely does not do this itself so as to provide maximum flexibility to consuming models."; uses http-client-identity-grouping; container proxy-connect { nacm:default-deny-write; if-feature "proxy-connect"; presence "Indicates that a proxy server connections have been configured. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "Configures the proxy server the HTTP-client is to connect thru."; choice proxy-type { mandatory true; description "Choice amongst proxy server types."; case http { container http-proxy { description "Container for HTTP Proxy (Web Proxy) server configuration parameters."; container tcp-client-parameters { description "A wrapper around the TCP parameters to avoid name collisions."; uses tcpc:tcp-client-grouping; } container http-client-parameters { description "A wrapper around the HTTP parameters to avoid name collisions."; uses http-client-identity-grouping; } } } case https { container https-proxy { description "Container for HTTPS Proxy (Secure Web Proxy) server configuration parameters."; container tcp-client-parameters { description "A wrapper around the TCP parameters to avoid name collisions."; uses tcpc:tcp-client-grouping; } container tls-client-parameters { description "A wrapper around the TLS parameters to avoid name collisions."; uses tlsc:tls-client-grouping; } container http-client-parameters { description "A wrapper around the HTTP parameters to avoid name collisions."; uses http-client-identity-grouping; } } } } } } // grouping http-client-grouping grouping http-client-stack-grouping { description "A grouping that defines common HTTP-based protocol stacks."; choice transport { mandatory true; description "Choice amongst various transports type. TCP, with and without TLS are defined here, with 'feature' statements so that they may be disabled. Other transports MAY be augmented in as 'case' statements by future efforts."; case tcp { if-feature "tcp-supported"; container tcp { description "Container for TCP-based HTTP protocols."; container tcp-client-parameters { description "A wrapper around the TCP parameters to avoid name collisions."; uses tcpc:tcp-client-grouping; } container http-client-parameters { description "A wrapper around the HTTP parameters to avoid name collisions."; uses http-client-grouping; } } } case tls { if-feature "tls-supported"; container tls { description "Container for TLS-based HTTP protocols."; container tcp-client-parameters { description "A wrapper around the TCP parameters to avoid name collisions."; uses tcpc:tcp-client-grouping; } container tls-client-parameters { description "A wrapper around the TLS parameters to avoid name collisions."; uses tlsc:tls-client-grouping; } container http-client-parameters { description "A wrapper around the HTTP parameters to avoid name collisions."; uses http-client-grouping; } } } } } // http-client-stack-grouping } ]]> <CODE ENDS>

The "ietf-http-server" Module This section defines a YANG 1.1 module called "ietf-http-server". A high-level overview of the module is provided in . Examples illustrating the module's use are provided in Examples. The YANG module itself is defined in .

Data Model Overview This section provides an overview of the "ietf-http-server" module in terms of its features and groupings.

Features The following diagram lists all the "feature" statements defined in the "ietf-http-server" module: The diagram above uses syntax that is similar to but not defined in .

Groupings The "ietf-http-server" module defines the following "grouping" statements:

• http-server-grouping
• http-server-stack-grouping

Each of these groupings are presented in the following subsections.

The "http-server-grouping" Grouping The following tree diagram illustrates the "http-server-grouping" grouping: Comments:

• The "http-server-grouping" defines the configuration for just "HTTP" part of a protocol stack. It does not, for instance, define any configuration for the "TCP" or "TLS" protocol layers (for that, see ).
• The "server-name" node defines the HTTP server's name, as presented to HTTP clients.
• The "client-authentication" node, which must by enabled by a feature, defines a very simple user-database. Only the "basic" authentication scheme is supported, albeit it must be enabled by a "feature". Other authentication schemes MAY be augmented in.

The "http-server-stack-grouping" Grouping The following tree diagram illustrates the "http-server-stack-grouping" grouping: Comments:

• The "http-server-stack-grouping" is a convenience grouping for downstream modules. It defines both the "HTTP" and "HTTPS" protocol stacks, with each option enabled by a "feature" statement for application control.
• For the referenced grouping statement(s):
  • The "tcp-server-grouping" grouping is discussed in .
  • The "tls-server-grouping" grouping is discussed in .
  • The "http-server-grouping" grouping is discussed in in this document.

Protocol-accessible Nodes The "ietf-http-server" module defines only "grouping" statements that are used by other modules to instantiate protocol-accessible nodes.

Example Usage This section presents an example showing the http-server-grouping populated with some data. foo.example.com ]]>

YANG Module This YANG module has normative references to . <CODE BEGINS> file "ietf-http-server@2022-12-12.yang" Author: Kent Watsen "; description "This module defines reusable groupings for HTTP servers that can be used as a basis for specific HTTP server instances. Copyright (c) 2022 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC GGGG (https://www.rfc-editor.org/info/rfcGGGG); see the RFC itself for full legal notices. 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 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here."; revision 2022-12-12 { description "Initial version"; reference "RFC GGGG: YANG Groupings for HTTP Clients and HTTP Servers"; } // Features feature client-auth-supported { description "Indicates that the configuration for how to authenticate clients can be configured herein. HTTP-level client authentication may not be needed when client authentication is expected to occur only at another protocol layer."; } feature local-users-supported { description "Indicates that the configuration for users can be configured herein, as opposed to in an application specific location."; } feature basic-auth { description "The 'basic-auth' feature indicates that the server may be configured authenticate users using the 'basic' HTTP authentication scheme."; reference "RFC 7617: The 'Basic' HTTP Authentication Scheme"; } feature tcp-supported { description "Indicates that the server supports HTTP/TCP."; } feature tls-supported { description "Indicates that the server supports HTTP/TLS."; } // Groupings grouping http-server-grouping { description "A reusable grouping for configuring an HTTP server. Note that this grouping uses fairly typical descendant node names such that a stack of 'uses' statements will have name conflicts. It is intended that the consuming data model will resolve the issue (e.g., by wrapping the 'uses' statement in a container called 'http-server-parameters'). This model purposely does not do this itself so as to provide maximum flexibility to consuming models."; leaf server-name { nacm:default-deny-write; type string; description "The value of the 'Server' header field. If not set, then underlying software's default value is used. Set to the empty string to disable."; } container client-authentication { if-feature "client-auth-supported"; nacm:default-deny-write; presence "Indicates that HTTP based client authentication is configured. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "Configures how the HTTP server can authenticate HTTP clients. The HTTP server will request that the HTTP client send authentication when needed."; container users { if-feature "local-users-supported"; description "A list of locally configured users."; list user { key "user-id"; description "The list of local users configured on this device."; leaf user-id { type string; description "The user-id for the authenticating client."; } choice auth-type { mandatory true; description "The authentication type."; case basic { container basic { if-feature "basic-auth"; leaf user-id { type string; description "The user-id for the authenticating client."; } leaf password { nacm:default-deny-write; type ianach:crypt-hash; description "The password for the authenticating client."; } description "The 'basic' HTTP scheme credentials."; reference "RFC 7617: The 'Basic' HTTP Authentication Scheme"; } } } } } } // container client-authentication } // grouping http-server-grouping grouping http-server-stack-grouping { description "A grouping that defines common HTTP-based protocol stacks."; choice transport { mandatory true; description "Choice amongst various transports type. TCP, with and without TLS are defined here, with 'feature' statements so that they may be disabled. Other transports MAY be augmented in as 'case' statements by future efforts."; case tcp { if-feature "tcp-supported"; container tcp { description "Container for TCP-based HTTP protocols."; container tcp-server-parameters { description "A wrapper around the TCP parameters to avoid name collisions."; uses tcps:tcp-server-grouping; } container http-server-parameters { description "A wrapper around the HTTP parameters to avoid name collisions."; uses http-server-grouping; } } } case tls { if-feature "tls-supported"; container tls { description "Container for TLS-based HTTP protocols."; container tcp-server-parameters { description "A wrapper around the TCP parameters to avoid name collisions."; uses tcps:tcp-server-grouping; } container tls-server-parameters { description "A wrapper around the TLS parameters to avoid name collisions."; uses tlss:tls-server-grouping; } container http-server-parameters { description "A wrapper around the HTTP parameters to avoid name collisions."; uses http-server-grouping; } } } } } // http-server-stack-grouping } ]]> <CODE ENDS>

Security Considerations

The "ietf-http-client" YANG Module The "ietf-http-client" YANG module defines "grouping" statements that are designed to be accessed via YANG based management protocols, such as NETCONF and RESTCONF . Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication. The Network Access Control Model (NACM) provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content. Since the module in this document only define groupings, these considerations are primarily for the designers of other modules that use these groupings. One readable data node defined in this YANG module may be considered sensitive or vulnerable in some network environments. This node is as follows:

• The "client-identity/basic/password" node:
  • The cleartext "password" node defined in the "http-client-identity-grouping" grouping is additionally sensitive to read operations such that, in normal use cases, it should never be returned to a client. For this reason, the NACM extension "default-deny-all" has been applied to it.

Please be aware that this module uses the "key" and "private-key" nodes from the "ietf-crypto-types" module , where said nodes have the NACM extension "default-deny-all" set, thus preventing unrestricted read-access to the cleartext key values. None of the writable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-write" extension has not been set for any data nodes defined in this module. Please be aware that this module uses groupings from the "ietf-tls-client" and "ietf-tls-server" modules defined in . All of the data nodes defined in these groupings have the NACM extension "default-deny-write" set, thus preventing unrestricted write-access to the data nodes defined in those groupings. This module does not define any RPCs, actions, or notifications, and thus the security consideration for such is not provided here.

The "ietf-http-server" YANG Module The "ietf-http-server" YANG module defines "grouping" statements that are designed to be accessed via YANG based management protocols, such as NETCONF and RESTCONF . Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication. The Network Access Control Model (NACM) provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content. Since the module in this document only define groupings, these considerations are primarily for the designers of other modules that use these groupings. None of the readable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-all" extension has not been set for any data nodes defined in this module. None of the writable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-write" extension has not been set for any data nodes defined in this module. Please be aware that this module uses groupings from the "ietf-tls-client" and "ietf-tls-server" modules defined in . All of the data nodes defined in these groupings have the NACM extension "default-deny-write" set, thus preventing unrestricted write-access to the data nodes defined in those groupings. This module does not define any RPCs, actions, or notifications, and thus the security consideration for such is not provided here.

IANA Considerations

The "IETF XML" Registry This document registers two URIs in the "ns" subregistry of the IETF XML Registry . Following the format in , the following registrations are requested:

The "YANG Module Names" Registry This document registers two YANG modules in the YANG Module Names registry . Following the format in , the following registrations are requested:

References Normative References In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK] This document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021. YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF). RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model. This document obsoletes RFC 6536. Informative References This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF). This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language. Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950.

Change Log

00 to 01

• Modified Abstract and Intro to be more accurate wrt intended applicability.
• In ietf-http-client, removed "protocol-version" and all auth schemes except "basic".
• In ietf-http-client, factored out "client-identity-grouping" for proxy connections.
• In ietf-http-server, removed "choice required-or-optional" and "choice local-or-external".
• In ietf-http-server, moved the basic auth under a "choice auth-type" limited by new "feature basic-auth".

01 to 02

• Removed the unused "external-client-auth-supported" feature from ietf-http-server.

02 to 03

• Removed "protocol-versions" from ietf-http-server based on HTTP WG feedback.
• Slightly restructured the "proxy-server" definition in ietf-http-client.
• Added http-client example show proxy server use.
• Added a "Note to Reviewers" note to first page.

03 to 04

• Added a parent "container" to "client-identity-grouping" so that it could be better used by the proxy model.
• Added a "choice" to the proxy model enabling selection of proxy types.
• Added 'http-client-stack-grouping' and 'http-server-stack-grouping' convenience groupings.
• Expanded "Data Model Overview section(s) [remove "wall" of tree diagrams].
• Updated the Security Considerations section.

04 to 05

• Fixed titles and a ref in the IANA Considerations section
• Cleaned up examples (e.g., removed FIXMEs)
• Fixed issues found by the SecDir review of the "keystore" draft.
• Updated the "ietf-http-client" module to use the new "password-grouping" grouping from the "crypto-types" module.

05 to 06

• Removed note questioning if okay for app to augment-in a 'path' node when needed, discussed during the 108 session.
• Addressed comments raised by YANG Doctor in the ct/ts/ks drafts.

06 to 07

• Added XML-comment above examples explaining the reason for the unusual top-most element's presence.
• Renamed 'client-auth-config-supported' to 'client-auth-supported' consistent with other drafts.
• Wrapped 'container basic' choice inside a 'case basic' per best practice.
• Aligned modules with `pyang -f` formatting.
• Fixed nits found by YANG Doctor reviews.

07 to 08

• Replaced "base64encodedvalue==" with "BASE64VALUE=" in examples.
• Minor editorial nits

08 to 09

• Fixed up the 'WG Web' and 'WG List' lines in YANG module(s)
• Fixed up copyright (i.e., s/Simplified/Revised/) in YANG module(s)

09 to 10

• NO UPDATE.

10 to 11

• Updated per Shepherd reviews impacting the suite of drafts.

11 to 12

• Updated per Shepherd reviews impacting the suite of drafts.

Acknowledgements The authors would like to thank for following for lively discussions on list and in the halls (ordered by first name): Ben Schwartz, Mark Nottingham, Mahesh Jethanandani, Rob Wilton (contributor), and Willy Tarreau.