Internet DRAFT - draft-pala-tian-eap-creds-spp
draft-pala-tian-eap-creds-spp
Network Working Group M. Pala
Internet-Draft Y. Tian
Intended status: Standards Track CableLabs
Expires: 2 November 2023 1 May 2023
Credentials Provisioning and Management via EAP Method (EAP-CREDS)
draft-pala-tian-eap-creds-spp-02
Abstract
With the increase number of devices, protocols, and applications that
rely on strong credentials (e.g., digital certificates, keys, or
tokens) for network access, the need for a standardized credentials
provisioning and management framework is paramount. The 802.1x
architecture allows for entities (e.g., devices, applications, etc.)
to authenticate to the network by providing a communication channel
where different methods can be used to exchange different types of
credentials. EAP-CREDS is an EAP method that specifically designed
for credential provisioning and management. If implemented in Access
Networks (e.g., wired), EAP-CREDS can offer credentials management
services such as registration, provisioning, and renewal. Besides,
EAP-CREDS provides protocol encapsulation mechanism that allows it to
use with other credential management protocols. Therefore, this
document defines how to use EAP-CREDS with the Simple Provisioning
Protocol (SPP) to support the provisioning and management of
authentication credentials for user and/or devices in an access
network. Other credential provisioning protocols can also use this
document as a guideline and template for its own encapsulation with
EAP-CREDS.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 2 November 2023.
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Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Overview of existing solutions . . . . . . . . . . . . . 4
2.2. Scope Statement . . . . . . . . . . . . . . . . . . . . . 5
2.3. EAP-CREDS as tunneled mechanism only . . . . . . . . . . 5
2.4. Fragmentation Support . . . . . . . . . . . . . . . . . . 5
2.5. Encapsulating Provisioning Protocols in EAP-CREDS . . . . 5
2.6. Algorithm Requirements . . . . . . . . . . . . . . . . . 6
2.7. Notation . . . . . . . . . . . . . . . . . . . . . . . . 6
3. EAP-CREDS Protocol . . . . . . . . . . . . . . . . . . . . . 7
3.1. Message Flow . . . . . . . . . . . . . . . . . . . . . . 7
3.2. Phase Transitioning Rules . . . . . . . . . . . . . . . . 8
3.3. Phase One: Initialization . . . . . . . . . . . . . . . . 8
3.4. Phase Two: Provisioning . . . . . . . . . . . . . . . . . 11
3.5. Phase Three: Validation . . . . . . . . . . . . . . . . . 13
4. EAP-CREDS Message Format . . . . . . . . . . . . . . . . . . 16
4.1. Message Header . . . . . . . . . . . . . . . . . . . . . 16
4.2. Message Payload . . . . . . . . . . . . . . . . . . . . . 18
4.3. EAP-CREDS defined TLVs . . . . . . . . . . . . . . . . . 20
4.3.1. The Action TLV . . . . . . . . . . . . . . . . . . . 20
4.3.2. The Certificate-Data TLV . . . . . . . . . . . . . . 20
4.3.3. The Challenge-Data TLV . . . . . . . . . . . . . . . 22
4.3.4. The Challenge-Response TLV . . . . . . . . . . . . . 22
4.3.5. The Credentials-Information TLV . . . . . . . . . . . 23
4.3.6. The Credentials-Data TLV . . . . . . . . . . . . . . 26
4.3.7. The Error TLV . . . . . . . . . . . . . . . . . . . . 26
4.3.8. The Network-Usage TLV . . . . . . . . . . . . . . . . 27
4.3.9. The Profile TLV . . . . . . . . . . . . . . . . . . . 29
4.3.10. The Protocol TLV . . . . . . . . . . . . . . . . . . 30
4.3.11. The Provisioning-Data TLV . . . . . . . . . . . . . . 30
4.3.12. The Provisioning-Headers TLV . . . . . . . . . . . . 31
4.3.13. The Provisioning-Params TLV . . . . . . . . . . . . . 31
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4.3.14. The Certificate-Request TLV . . . . . . . . . . . . . 34
4.3.15. The Storage-Info TLV . . . . . . . . . . . . . . . . 35
4.3.16. The Formats TLV . . . . . . . . . . . . . . . . . . . 36
4.3.17. The Supported-Encoding TLV . . . . . . . . . . . . . 37
4.3.18. The Token-Data TLV . . . . . . . . . . . . . . . . . 37
4.3.19. The Version TLV . . . . . . . . . . . . . . . . . . . 38
5. EAP-CREDS Messages . . . . . . . . . . . . . . . . . . . . . 38
5.1. The EAP-CREDS-Init Message . . . . . . . . . . . . . . . 39
5.1.1. EAP Server's Init Message . . . . . . . . . . . . . . 39
5.1.2. EAP Peer's Init Message . . . . . . . . . . . . . . . 40
5.1.3. The EAP-CREDS-Provisioning Message . . . . . . . . . 41
5.1.4. The EAP-CREDS-Validate Message . . . . . . . . . . . 42
6. Error Handling in EAP-CREDS . . . . . . . . . . . . . . . . . 43
7. The Simple Provisioning Protocol (SPP) . . . . . . . . . . . 43
7.1. SPP Message Format . . . . . . . . . . . . . . . . . . . 44
7.2. SPP Message Flow . . . . . . . . . . . . . . . . . . . . 44
7.2.1. SPP Symmetric Secrets Management . . . . . . . . . . 46
7.2.2. SPP Key Pair Provisioning . . . . . . . . . . . . . . 50
7.2.3. SPP Certificate Provisioning . . . . . . . . . . . . 50
7.2.4. SPP Token Provisioning . . . . . . . . . . . . . . . 51
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 51
8.1. Provisioning Protocols . . . . . . . . . . . . . . . . . 51
8.2. Token Types . . . . . . . . . . . . . . . . . . . . . . . 52
8.3. Credentials Types . . . . . . . . . . . . . . . . . . . . 53
8.4. Credentials Algorithms . . . . . . . . . . . . . . . . . 53
8.5. Credentials Datatypes . . . . . . . . . . . . . . . . . . 54
8.6. Challenge Types . . . . . . . . . . . . . . . . . . . . . 54
8.7. Network Usage Datatypes . . . . . . . . . . . . . . . . . 55
8.8. Credentials Encoding . . . . . . . . . . . . . . . . . . 55
8.9. Action Types . . . . . . . . . . . . . . . . . . . . . . 56
8.10. Usage Metadata Types . . . . . . . . . . . . . . . . . . 56
9. Security Considerations . . . . . . . . . . . . . . . . . . . 56
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 57
11. Normative References . . . . . . . . . . . . . . . . . . . . 57
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 58
1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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2. Introduction
Many environments are, today, moving towards requiring strong
authentication when it comes to gain access to networks. However,
the provisioning and management of these credentials is a hard
problem to solve and many vendors opt for long-lived credentials that
can not be easily revoked, replaced, or simply renewed. The 802.1x
architecture provides network administrators with the possibility to
check credentials presented by a device even before providing any
connectivity or IP services to it. This specification addresses the
problem of providing a simple-to-use and simple-to-deploy conduit for
credentials management by extending the EAP protocol to support
credentials provisioning and management functionality. In
particular, the EAP-CREDS method defined in provides a generic
framework that can carry the messages for provisioning different
types of credentials. EAP-CREDS implements the Simple Provisioning
Protocol (SPP) which comprises of a series of messages that enable
the management not only of certificates, but also of other types of
credentials like username/password pairs, asymmetric keys, and
symmetric keys. EAP-CREDS cannot be used as a stand-alone method.
It is required that EAP-CREDS is used as an inner method of EAP-TLS,
EAP-TEAP, or any other tunnelling method that can provide the
required secrecy and (at minimum) server-side authentication to make
sure that the communication is protected and with the right server.
2.1. Overview of existing solutions
Currently, there are many protocols that address credentials
lifecycle management. Particularly, when it comes to digital
certificates, some of the most deployed management protocols are:
Certificate Management Protocol (CMP) [RFC4210], Certificate
Management over CMS (CMC) [RFC5272][RFC6402], Enrollment over Secure
Transport (EST) [RFC7030], and Automated Certificate Management
Environment (ACME) . However, none of these protocols provide native
support for client that do not have IP connectivity yet (e.g.,
because they do not have network-access credentials, yet). EAP-CREDS
provides the possibility to use such protocols (i.e., message-based)
by defining a series of messages that can be used to encapsulate the
provisioning messages for the selected provisioning protocol. In
addition to these protocols, EAP-CREDS also defines a series of
simple messages that provide a generic enrollment protocol that
allows not only certificates but also other types of credentials
(e.g., username/password pairs, tokens, or symmetric secrets) to be
delivered to the client as part of the provisioning and/or renewal
process. The set of messages that make up the generic provisioning
protocol is referred to as the Simple Provisioning Protocol protocol
or SPP.
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2.2. Scope Statement
This document focuses on the definition of the EAP-CREDS method to
convey credentials provisioning and managing messages between the
client and the AAA server. Moreover, the document defines how to
encode messages for the main IETF provisioning protocols. This
document, however, does not provide specifications for how and where
the credentials are generated. In particular, the credentials could
be generated directly within the AAA server or at a different
location (i.e., the Certificate Service Provider or CSP) site.
Different authentication mechanisms (e.g., TLS, etc.) can be used to
secure the communication between the server's endpoint and the CSP.
2.3. EAP-CREDS as tunneled mechanism only
EAP-CREDS requires that an outer mechanism is in place between the
Peer and the Server in order to provide authentication and
confidentiality of the messages exchanged via EAP-CREDS. In other
words, EAP-CREDS assumes that an appropriatly encrypted and
authenticated channel has been established to prevent the possibility
to leak information or to allow man-in-the-middle attacks.
This choice was taken to simplify the message flow between Peer and
Server, and to abstract EAP-CREDS from the secure-channel
establishment mechanism. EAP-TLS, or EAP-TEAP are examples of such
mechanisms.s
2.4. Fragmentation Support
EAP does not directly support handling fragmented packets and it
requires the outer method to provide fragmentation support.
Because of the outer method requirements in particular, removing any
support for fragmented messages in EAP-CREDS removes the duplication
of packets (e.g., Acknowledgment Packets) sent across the Peer and
the Server, thus resulting in a smaller number of exchanged messages
2.5. Encapsulating Provisioning Protocols in EAP-CREDS
In order to use EAP-CREDS together with your favorite provisioning
protocol, the messages from the provisioning protcol need to be sent
to the other party. In EAP-CREDS, this is done by encoding the
provisioning protocol messages inside the ('Provisioning-Data') TLV.
In case the provisioning protocol uses additional data for its
operations (e.g., uses HTTP Headers), this data can be encoded in a
separate ('Provisioning-Headers') TLV.
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Since the implementation of the provisioning endpoint could happen in
a (logically or physically) different component, a method is needed
to identify when a provisioning protocol has actually ended. In EAP-
CREDS, the 'D' bit in the message headers is used for this purpose.
In the first message of Phase Two, the Server provides the client
with all the selected parameters for one specific credential that
needs attention (or for a new credential) to be managed by the
network. In particular, the server provides, at minimum, the
('Protocol') TLV, the ('Action') TLV, and the ('Provisioning-Params')
or the ('Credentials-Info') TLV.
After checking the parameters sent by the Server, if the Peer does
not support any of the proposed ones, it MUST send a message with one
single ('Error') TLV with the appropriate error code(s). The server,
can then decide if to manage a different set of credentials (if more
where reported by the Peer in its Phase One message) or if to
terminate the EAP session with an error.
The Peer and the Server exchange Provisioning messages until an error
is detected (and the appropriate error message is sent to the other
party) or until Phase Two is successfully completed.
2.6. Algorithm Requirements
EAP-CREDS uses the SHA-256 hashing algorithm to verify credentials in
phase three of the protocol. Peers and Servers MUST support SHA-256
for this purpose.
2.7. Notation
In this document we use the following notation in the diagrams to
provide information about the cardinality of the data structures
(TLVs) within EAP-CREDS messages:
+--------+------------+---------------------------------------------+
| Symbol | Example | Usage |
+--------+------------+---------------------------------------------+
| { } | {TLV1} | Curly Brackets are used to indicate a set |
| [ ] | {[TLV2]} | Square Brackets are used to indicate that a |
| | | field is optional |
| ( ) | {TLV1(=V)} | Round Squares are used to specify a value |
| + | {TLV_2+} | The Plus character indicates that one or |
| | | more instances are allowed |
+--------+------------+---------------------------------------------+
Figure 1: EAP-CREDS Notation
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3. EAP-CREDS Protocol
In a nutshell, EAP-CREDS provides the abstraction layer on top of
which credentials provisioning/managing protocols can be deployed
thus enabling their use even before provisioning IP services.
This section outlines the operation of the protocol and message
flows. The format of the CREDS messages is given in Section 4.
3.1. Message Flow
EAP-CREDS message flow is logically subdivided into three different
phases: Initialization, Provisioning, and Validation. EAP-CREDS
enforces the order of phases, i.e. it is not possible to move to an
earlier phase.
Phase transitioning is controlled by the Server. In particular, the
server, after the last message of a phase, it can decide to either
(a) start the next phase by sending the first message of the next
phase, or (b) continue the same phase by sending another "first"
message of the phase (e.g., managing a second set of credentials) -
this is allowed only in Phase Two and Phase Three but NOT in Phase
One, or (c) terminate the EAP session.
Phase One (Required). Initialization. During this phase the Peer
and the Server exchange the information needed to select the
appropriate credentials management protocol. Phase One flow is
composed by only messages. In particular, the Sever sends its
initial message of type ('EAP-CREDS-Init'). The Peer replies with
the details about which provisioning protocols are supported, and
additional information such as the list of installed credentials
and, optionally, authorization data (for new credentials
registration).
Phase Two (Optional). Provisioning Protocol Flow. In this phase,
the Peer and the Server exchange the provisioning protocol's
messages encapsulated in a EAP-CREDS message of type Provisioning.
The messages use two main TLVs. The first one is the
('Provisioning-Headers') TLV which is optional and carries
information that might be normally coveyed via the transport
protocol (e.g., HTTP headers). The second one is the
('Provisioning-Data'), which is required and carries the
provisioning protocol's messages. The server can decide to repeat
phase two again to register new credentials or to renew a separate
set of credentials by issuing a new ('Provisioning') message for
the new target. When no more credentials have to be managed, the
Server can start phase three or simply terminate the EAP session.
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Phase Three (Optional). Credentials Validation. This optional
phase
can be initiated by the server and it is used to validate that the
Peer has properly installed the credentials and can use them to
authenticate itself. Depending on the credentials' type, the
messages can carry a challenge/nonce, the value of the secret/
token, or other information. The format of the credentials is
supposed to be known by the provider and the device.
3.2. Phase Transitioning Rules
In order to keep track of starting and ending a phase, EAP-CREDS
defines several bits and fields in the EAP-CREDS message headers. In
particular, as described in Section 4.1, the 'S' bit is used to
indicate the beginning (or Start) of a phase, while the 'Phase' field
(4 bits) is used to indicate the phase for this message.
In EAP-CREDS, phase transitioning is under the sole control of the
Server, therefore the value of the 'S' bit is meaningful only in
messages sent by the Server. The value of the 'S' bit in Peer's
messages SHALL be set to '0x0' and SHALL be ignored by the server.
When starting a new phase, the Server MUST set the 'S' bit to '1' and
the 'Phase' field to the current phase number (e.g., one, two, or
three).
In case the first message of a phase is to be repeated (e.g., because
of processing multiple credentials), the 'S' bit SHALL be set to '0'
(i.e., it should be set to '1' only on the first occurrency and set
to '0' in subsequent messages).
3.3. Phase One: Initialization
The following figure provides the message flow for Phase One:
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,--------. ,----------.
|EAP Peer| |EAP Server|
`---+----' `----+-----'
| Outer Tunnel Established |
| <-------------------------------------->
| |
| [1] EAP-Request/EAP-CREDS(Type=Init) | ,---------!.
| { [ Version+ ], [ Challenge-Data ] } | |Phase One|_\
| <--------------------------------------- |Begins |
| | `-----------'
| [2] EAP-Response/EAP-CREDS(Type=Init) |
| { [Version], [ Protocols+ ], |
| [ Creds-Info+ ], [ Encoding+ ] | ,---------!.
| [ Format+ ], [ Token-Data ] | |Phase One|_\
| [ Profile+ ], [ Challenge-Rsp ] | |Ends |
| [ Storage-Info ],[ Net-Usage] } | `-----------'
| --------------------------------------->
| |
| |
EAP-CREDS Phase One Message Flow
[1] Server sends EAP-Request/EAP-CREDS(Type=Init):
After the establishment of the outer mechanism (e.g., EAP-TLS,
EAP-TEAP, EAP-TTLS, etc.), the server MAY decide to start a
credentials management session. In order to do that, the Server
sends an EAP-Request/EAP-CREDS(Type=Init) message to the Peer with
the 'Phase' field sets to '0x01'. The 'S' bit also needs to be
set to '1', which indicates this message is the beginning of Phase
One. Also, the Server MAY use one or more ('Version') TLVs to
indicate the supported versions.
The Server MAY also specify which versions of EAP-CREDS are
supported by adding one or more ('Version') TLVs. If no
('Version') TLV is added to the message, the Peer SHOULD assume
the supported version is 1 ('0x1').
Optionally, the Server MAY also send a ('Challenge-Data') TLV
which includes chanllenge data value (usually some random value)
and a specified challenge type, which indicates the type Peer MUST
use for calculating the ('Challenge-Response') TLV.
[2] The Peer sends EAP-Response/EAP-CREDS(Type=Init)
The Peer, sends back a message that carries one ('Version') TLV to
indicate the selected version of EAP-CREDS (i.e. from the list
provided by the server) (optional). If the client does not
include the ('Version') TLV, the Server MUST use the most recent
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supported version of EAP-CREDS. Moreover, the Server includes one
or more ('Protocol') TLVs to indicate the list of supported
provisioning protocols, followed by one or more ('Credentials-
Info') TLVs for each installed credential to provide their status
to the server (i.e., if multiple credentials are configured on the
Peer for this Network, then the Peer MUST include one
('Credentials-Info') TLV for each of them).
The Peer also provides the list of supported Encodings and Formats
by adding one or more ('Encodings') and ('Formats') TLVs.
When there are no abailable credentials, the Peer MAY include an
authorization token that can be consumed by the Server for
registering new credentials. In particular, the Peer can include
the ('Token-Data') TLV to convey the value of the token. The
('Challenge-Data') and ('Challenge-Response') TLVs, instead, can
be used to convey a challenge and its response based on the
authorization information (e.g., maybe a public key hash is
present in the Token, then the peer can generate some random data
- or use the one from the Server - and generate a signature on
that value: the signature SHALL be encoded in the ('Challenge-
Response') TLV and it should be calculated over the concatenation
of values inside the ('Challenge-Data') TLV and the ('Token-Data')
TLV.
Also, the Peer MAY add one or more ('Profile') TLVs to indicate to
the Server which profiles are requested/supported (e.g., a pre-
configuration MAY exist on the Peer with these ecosystem-specific
identifiers).
Ultimately, the Peer MAY include additional metadata regarding the
status of the Peer. To this end, the Peer can use a ('Storage-
Info') TLV to provide the server with additional data about the
Peer's capabilities and resources (e.g., credentials storage).
Also, the ('Network-Usage') TLV can be used to provide the Server
with the indication of which network resources are needed by the
Peer and what is its intended utilization pattern(s).
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The server checks that the Peer's selected protocol, version, and
parameters are supported and, if not (or if the server detects an
error), it can (a) send a non-recoverable error message to the
peer, notify the outer (tunneling) layer, and terminate the EAP-
CREDS session, or (b) start phase one again by sending a new
('EAP-CREDS-Init') message that will also carry an ERROR TLV that
provides the Peer with the reason the initial response was not
acceptable. In this case, the 'Phase' field MUST be omitted since
it is not the first message of phase one (see Section 3.2). The
server and the peer can repeat phase one until they reach an
agreement or the session is terminated by the Server.
NOTE WELL: The determination of the need to start Phase Two or not
is based on the contents of the ('Credentials-Info') TLV sent by
the Peer (e.g., a credential is about to expire or a credential is
simply missing).
3.4. Phase Two: Provisioning
The following figure provides the message flow for Phase 2:
,--------. ,----------.
|EAP Peer| |EAP Server|
`---+----' `----+-----'
| [1] EAP-Request/EAP-CREDS(Type=Provisioning) |
| { Protocol, Action, | ,---------!.
| [ CredInfo ], [ Params ], | |Phase Two|_\
| [ ProtoData ], [ ProtoHeaders ] } | |Begins |
| <---------------------------------------------- `-----------'
| |
| [2] EAP-Response/EAP-CREDS(Type=Provisioning) |
| { ProtoData, [ ProtoHeaders ] } |
| ---------------------------------------------->
| |
. .
. .
. .
. .
| [N] EAP-Response/EAP-CREDS(Type=Provisioning) |
| { [ CredInfo ], [ ProtoData ], |
| [ ProtoHeaders ] } |
| <----------------------------------------------
| |
| [N+1] EAP-Request/EAP-CREDS(Type=Provisioning)| ,---------!.
| { [ ProtoData ], [ ProtoHeaders ] } | |Phase Two|_\
| ----------------------------------------------> |Ends |
| | `-----------'
| |
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EAP-CREDS Phase Two Message Flow
[1] The Server sends EAP-Request/EAP-CREDS(Type=Init)
The first message of Phase Two indicates that the Server is ready
to initiate the selected provisioning protocol.
[2] The Peer sends EAP-Response/EAP-CREDS(Type=Init)
After that, the Peer sends its first message to the Server by
sending the EAP-Response/EAP-CREDS(Type=Provisioning) message.
This message contains the selected provisioning protocol's message
data and some extra fields (e.g., transport-protocol headers) in
the ('Provisioning-Data') and ('Protocol-Headers') TLVs
respectively.
[3] The Server sends EAP-Request/EAP-CREDS(Type=Init)
The Server replies to the Peer's message with EAP-Request/EAP-
CREDS(Type=Provisioning) messages until the provisioning protocol
reaches an end or an error condition arise (non-recoverable).
[N] The Server sends EAP-Request/EAP-CREDS(Type=Provisioning)
When the provisioning protocol has been executed for the specific
set of credentials, the server sends a last message that MUST
include the description of the provisioned credentials in a
('Credentials-Info') TLV and MUST set the 'D' bit in the EAP-CREDS
message header to '1' to indicates that the server does not have
any more ('Provisioning') messages for this credenital. The final
message does not need to be an empty one, i.e. other TLVs are
still allowed in the same message (e.g., the 'Provisioning-Data'
and the 'Provisioning-Headers' ones).
[N+1] The Peer sends EAP-Request/EAP-CREDS(Type=Provisioning)
The Peer MUST reply to the server with a ('Provisioning') message
that MUST have the 'D' bit in the EAP-CREDS message header set to
'1', thus indicating that the credentials have been installed
correctly. In case of errors, the Peer MUST include the
appropriate ('Error') TLV. Also in this case, the final message
does not need to be an empty one, i.e. other TLVs are still
allowed in the same message (e.g., the 'Provisioning-Data' and the
'Provisioning-Headers' ones).
At this point, the Server can decide to provision (or manage) another
set of credentials by issuing a new ('Provisioning') message, or it
can decide to start Phase Three by sending its first ('Validate')
message, or it can terminate the EAP session.
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3.5. Phase Three: Validation
The following figure provides the message flow for Phase 3:
,--------. ,----------.
|EAP Peer| |EAP Server|
`---+----' `----+-----'
| [1] EAP-Request/EAP-CREDS(Type=Validate) | ,-----------!.
| { Cred-Info, Challenge-Data } | |Phase Three|_\
| <----------------------------------------- |Begins |
| | `-------------'
| [2] EAP-Response/EAP-CREDS(Type=Validate)| ,-----------!.
| { Challenge-Response } | |Phase Three|_\
| -----------------------------------------> |Ends |
| | `-------------'
| |
EAP-CREDS Phase Three Message Flow (Basic)
Phase three is optional and it is usually used by the server to
request the client to validate (proof) that the new credentials have
been installed correctly before issuing the final Success message.
However, it is also possible for the Peer to request the server-side
validation for symmetric credentials. The message flow and diagram
of the server-side validation is listed below in this section.
NOTE WELL: Phase Three introduces a dependency on the selected
hashing algorithm to provide common and easy way to check the
integrity and functionality of a newly installed set of
credentials.
[1] The Server sends EAP-Request/EAP-CREDS(Type=Validate)
In order to start Phase Three, the Server sends an EAP-Request/
EAP-CREDS(Type=Validate) message to the Peer. The Server MUST
include the ('Credentials-Info') TLV to provide the indication
about which set of credentials the Server intends to validate.
The Server MUST also include a randomly generated challenge in the
message to the client. The type of challenge determines how the
('Challenge-Response') is calculated. EAP-CREDS defines the
asymmetric and symmetric challenges in Section 8.6 and others can
be defined according to the specified rules.
As usual, the Server MUST set, in the headers, the 'S' bit to '1'
in its first message of Phase Three and the 'Phase' value shall be
set to '3' (beginning of Phase Three).
[2] The Peer sends EAP-Response/EAP-CREDS(Type=Validate)
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When the client receives the Validate message from the server, it
calculates the response to the challenge and sends the response
back to the server in a EAP-Response/EAP-CREDS(Type=Validate)
message. When the EAP-CREDS-ASYMMETRIC-CHALLENGE and EAP-CREDS-
SYMMETRIC-CHALLENGE values are used in the Challenge type, the
Peer MUST calculate the response as follows:
Public-Key
For any public-key based credentials (e.g., certificates or raw
key pairs), the response to the challenge is calculated by
generating a signature over the hashed value of the challenge.
The hashing algorithm to be used for this purpose is specified
in Section 2.6. The format of the signature in the
('Challenge-Response') TLV is the concatenation of:
* The signatureAlgorithm (DER encoded) which contains the
identifier for the cryptographic algorithm used by the Peer
to generate the signature. [RFC3279], [RFC4055], and
[RFC4491] list supported signature algorithms, but other
signature algorithms MAY also be supported. The definition
of the signatureAlgorithm is provided in Section 4.1.1.2 of
[RFC5280].
* The signatureValue (DER encoded) which contains the digital
signature itself. The signature value is encoded as a BIT
STRING and the details of how to generate the signatures'
structures can be found in Section 4.1.1.3 of [RFC5280] and
referenced material.
Symmetric Secret
For any symmetric based credentials (e.g., password or Key),
the response to the challenge is calculated by using the
selected hash function (see Section 2.6) on the concatenation
of (a) the value carried in the server- provided ('Challenge-
Data') TLV, and (b) the secret value itself (salted hash).
The initial values for the type of challenges are described in
the Section 8.6. Other types of challenges MAY be defined
according to the specified procedures.
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,--------. ,----------.
|EAP Peer| |EAP Server|
`---+----' `----+-----'
| [1] EAP-Request/EAP-CREDS(Type=Validate) | ,-----------!.
| { Cred-Info, Challenge-Data } | |Phase Three|_\
| <----------------------------------------- |Begins |
| | `-------------'
| [2] EAP-Response/EAP-CREDS(Type=Validate)|
| { Challenge-Response, Challenge-Data } |
| ----------------------------------------->
| |
| [3] EAP-Response/EAP-CREDS(Type=Validate)| ,-----------!.
| { Challenge-Response } | |Phase Three|_\
| <----------------------------------------| |Ends |
| | `-------------'
EAP-CREDS Phase Three Message Flow (Server-side Validation)
[1] The Server sends EAP-Request/EAP-CREDS(Type=Validate)
In order to start Phase Three, the Server sends an EAP-Request/
EAP-CREDS(Type=Validate) message to the Peer. The Server MUST
include the ('Credentials-Info') TLV to provide the indication
about which set of credentials the Server intends to validate.
The Server MUST also include a randomly generated challenge in the
message to the client. The type of challenge determines how the
('Challenge-Response') is calculated. EAP-CREDS defines the
asymmetric and symmetric challenges in Section 8.6 and others can
be defined according to the specified rules.
As usual, the Server MUST set, in the headers, the 'S' bit to '1'
in its first message of Phase Three and the 'Phase' value shall be
set to '3' (beginning of Phase Three).
[2] The Peer sends EAP-Response/EAP-CREDS(Type=Validate)
When the client receives the Validate message from the server, it
calculates the response to the challenge and sends the response
back to the server in a EAP-Response/EAP-CREDS(Type=Validate)
message. Besides, the Peer MAY include ('Challenge-Data') TLV for
the server-side validation.
[3] The Server sends EAP-Request/EAP-CREDS(Type=Validate)
When the Server receives the response message from the Peer with
('Challenge-Data') included, the Server MUST include (if a
symmetric secret) the response to the Peer-issued ('Challenge-
Data') TLV by computing the response and adding it to the
('Challenge-Response') TLV in its reply.
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Finally, in the last message, the Server (if Phase Three is to be
ended) SHALL set the 'S' bit to '0' (end of phase) and the value
of 'Phase' field set to '0x03'.
In case of issues with the validation of newly deployed credentials,
both the Server and the Peer should consider those credentials
invalid (or unusable) and should issue the required failure
message(s).
4. EAP-CREDS Message Format
The EAP-CREDS defines the following message types:
1. EAP-CREDS/Init
2. EAP-CREDS/Provisioning
3. EAP-CREDS/Validate
Each of these message types have the basic structure as identified in
Section 4.1. EAP-CREDS messages contain zero, one, or more TLVs.
The internal structure of the different types of TLVs is described in
Section 4.2, while a detailed description of the EAP-CREDS message
types is provided in Section 5.
4.1. Message Header
The EAP-CREDS messages consist of the standard EAP header (see
Section 4 of [RFC3748]), followed by the version of the EAP-CREDS (4
bits) and a field (4 bits) reserved for future use. The header has
the following structure:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Identifier | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type |J|S|F|D| Phase | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Length | Data ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-.
Where the Code, Identifier, Length, and Type fields are all part of
the EAP header as defined in [RFC3748]. Since EAP-CREDS can only be
used as a tunneled mechanism, the presence of these fields is only
for backward compatibility with existing parsers. In particular, the
'Length' field is not used (can be ignored): the message length is
carried in the 'Message Length' field instead.
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The Type field in the EAP header is <TBD> for EAP-CREDS.
The Flags bitfield is used to convey status information (e.g., extra
long message, phase number, phase transitioning state). The
transition-control bit (i.e., the 'S' bit) are set in Server's
messages and are ignored in Peer's messages (the Server is the entity
that unilaterally controls the phase transition process). The
meanins of the bits in the 'Flags' field are as follows:
Bit 'J' (Jumbo Message) - If set, it idicates the presence of the
'Message Length' field. This bit SHALL be used only when the size
of the message exceeds the maximum value allowed in the 'Length'
field. In this case, the 'Message Length' field is added to the
message and set to the whole message size and the 'Length' field
is used for the current fragment length. If not set, the 'Message
Length' field is not present in the Message and the 'Length' field
is used for the message size (and the 'F' bit MUST be set to '0').
Bit 'S' (Start) - If set, this message is the first one of a new
EAP-CREDS phase. The value of the new phase is encoded in the
'Phase' field.
Bit 'F' - If set, this message is a fragment of a message. In
this case, the 'Data' field is to be concatenated with all
messages with the 'F' bit set to '1' until the message with the
'F' bit set to '0' that indicates the end of the message. If the
message is not fragmented, the 'F' bit MUST be set to '0'. The
use of this bit is required when the tunneling method does not
provide support for messages up to 2^32 bits in size.
Bit 'D' - This bit is used in Phase Two and Phase Three to
indicate that the specific operation for the identified credential
is over. For example, when multiple credentials exist on the Peer
and the Server needs to manage and validate one of them. In its
last message, when the provisioning protocol is done, the server
sets the 'D' (Done) bit to indicate that it is done. The Peer, in
its reply, sets the bit to indicate the end of provisioning for
this credentials is also over. After that, the Server can
continue Phase Two, transition to Phase Three, or terminate the
EAP session.
The Phase field is a 4-bits value and identifies the EAP-CREDS phase
for the current message. The version of EAP-CREDS described in this
document supports three values for this field:
0x01 - Phase One
0x02 - Phase Two
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0x03 - Phase Three
A detailed explanation of the 'Phase' and 'Flags' fields of the
message headers is provided in Section 3.2.
The Data field is the message payload. The full description of this
field is provided in the next section.
4.2. Message Payload
The Data part of the message is organized as zero, one, or more TLV
objects whose structure is defined in this section.
Each TLV object has the same basic structure that is defined as
follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where:
TLV-Type (uint8)
This field is used to indicate the type of data that the TLV
carries. The type of TLV determines its internal structure. The
supported values for this fields are provided in the following
table:
Length (uint24)
This field carries the size of the value of the TLV. In
particular, the overall size of a TLV (i.e., the header plus the
value) can be calculated by adding the size of the header (6
octects) to the value of the Length field (i.e., the size of the
TLV's value).
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+==========+==========================+========================+
| TLV Name | TLV Type | Scope/Usage |
+==========+==========================+========================+
| <TBD> | Action TLV | Phase Two |
+----------+--------------------------+------------------------+
| <TBD> | Certificate-Data TLV | Phase Two/SPP |
+----------+--------------------------+------------------------+
| <TBD> | Challenge-Data TLV | Phase Two, Phase Three |
+----------+--------------------------+------------------------+
| <TBD> | Challenge-Response TLV | Phase Two, Phase Three |
+----------+--------------------------+------------------------+
| <TBD> | Credentials-Data TLV | Phase Two/SPP |
+----------+--------------------------+------------------------+
| <TBD> | Credentials-Info TLV | Phase Two, Phase Three |
+----------+--------------------------+------------------------+
| <TBD> | Error TLV | All Phases |
+----------+--------------------------+------------------------+
| <TBD> | Network-Usage TLV | Phase One |
+----------+--------------------------+------------------------+
| <TBD> | Profile TLV | Phase Two |
+----------+--------------------------+------------------------+
| <TBD> | Protocol TLV | Phase One, Phase Two |
+----------+--------------------------+------------------------+
| <TBD> | Provisioning-Data TLV | Phase Two |
+----------+--------------------------+------------------------+
| <TBD> | Provisioning-Headers TLV | Phase Two |
+----------+--------------------------+------------------------+
| <TBD> | Provisioning-Params TLV | Phase Two |
+----------+--------------------------+------------------------+
| <TBD> | Certificate-Request TLV | SPP |
+----------+--------------------------+------------------------+
| <TBD> | Storage-Info TLV | SPP |
+----------+--------------------------+------------------------+
| <TBD> | Supported-Format TLV | SPP |
+----------+--------------------------+------------------------+
| <TBD> | Supported-Encoding TLV | SPP |
+----------+--------------------------+------------------------+
| <TBD> | Token-Data TLV | Phase One |
+----------+--------------------------+------------------------+
| <TBD> | Version TLV | Phase One |
+----------+--------------------------+------------------------+
Table 1: EAP-CREDS Supported TLVs Types
TLV Value ( > 1 octet )
This field carries data for the identified TLV. The internal
structure is determined by the TLV Type field.
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The rest of this section describes the structure of the different
supported TLVs and their usage in the different messages.
4.3. EAP-CREDS defined TLVs
EAP-CREDS messages's payload comprieses zero, one, or more TLVs that
are encoded in a single EAP-CREDS message. The values for the TLV
Type that are supported by this specifications are listed in Table 2.
4.3.1. The Action TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Action Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Action TLV
TLV Length (uint24)
Fixed value (=2)
Flags (uint8)
Reserved
4.3.2. The Certificate-Data TLV
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Encoding | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Certificate-Data TLV
Length (uint24)
Provides the length of the TLV (> 3 octets)
Flags (uint8)
Provides a BITMASK that can be used to provide additional
information related to the encapsulated certificate. The bits
have the following meaning:
Bit 0 - If set, the certificate is trusted (Trust Anchor) Bit 1
- If set, the certificate is a CA certificate
Bit 2 - If set, the certificate is self-signed
Bit 3 - If set, the certificate is a proxy certificate
Bit 4 - If set, the certificate is an attribute certificate
Bit 5 - Reserved
Bit 6 - Reserved
Bit 7 - Reserved
For a Trusted Root CA, the value of the flags shall be 0x7 (0000
0111). For an intermediate CA certificate that is not implicitly
trusted, the value of the flags field should be set to 0x02 (0000
0010). For an End-Entity certificate, the value of the Flags will be
0x0 (0000 0000).
Format (uint8)
Provides the indication of the Format the certificate is in. The
allowed values for this field are listed in Section 8.5.
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Encoding (uint8)
Provides the indication of the Encoding the certificate is in.
The allowed values for this field are listed in Section 8.8.
Value (octet string)
This field carries the data for the certificate.
4.3.3. The Challenge-Data TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ch. Type | Challenge Data ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Challenge-Data TLV
Length (uint24)
3 octets
Challenge Type (uint8).
This field carries the type of Challenge. In particular, the
challenge type determines how the Peer MUST calculate the
('Challenge-Response'). The initial values for this fiel are
listed in Section 8.6. Please refer to Section 3.5 for a detailed
explanation of how to calculate the response to the challenge for
the challenge types defined in this document.
Challenge Data (> 1 octet)
This field carries the data to be used as a challenge when
validating newly deployed credentials.
4.3.4. The Challenge-Response TLV
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Challenge Response ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Challenge-Response TLV
Length (uint24)
3 octets
Challenge Response (> 1 octet)
This field carries the data that resulted from the use of the
credentials to be validated.
4.3.5. The Credentials-Information TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | CredsType | ProtoID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IssuedOn (GMT) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Expires On (GMT) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credentials Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CredIDValue ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Credential-Information TLV is used by the Peer to provide a
description of the installed credentials that are relevant for the
network that is being accessed.
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For example, when a set of credentials need to be renewed, the server
checks the ('Credentials-Info') from the Peer and eventually selects
the right one for renewal. The TLV structure is as follows:
TLV Type (uint8)
<TBD> - Credentials-Information TLV
Length (uint24)
Provides the total length of the body of the Credential-
Information TLV.
Flags (uint8)
Provides a BITMASK that can be used to provide information about
the status of the credentials (e.g., if the use marks the
credentials to be compromised). The bits have the following
meaning:
Bit 0 - If set, the credential is marked as compromised
Bit 1 - If set, the credential is immutable and cannot be updated
Bit 2 - Private Key or Secret Immutable, the public part of the
credential (e.g., a certificate) can still be updated
Bit 3 - If set, the credential cannot be updated (both public and
private parts)
Bit 4 - If set, the credential is ready to be used
Bit 5 - If set, the credential was generated on the server
Bit 6 - If set, the Peer would like to update the credential even
if they are not expired
Bit 7 - Reserved
CredType (uint8)
This field provides the description of the type of credential.
The type of credentials are listed in Section 8.3
ProtoID (uint16)
This field indicates the protocol that was used to retrieve the
target credential. When the TLV is used in a Request by the
Server, this field is ignored. The values for this field are
listed in Section 8.1.
IssuedOn (16 octets)
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This field carries the GMT date for when this credential was
issued. This field is 16 bytes long (the last byte must be set to
'0x00') and contains the NULL-terminated ASCII string that
represents the timestamp where the credential was issued. When
the value is not set, the field should be set to { 0x00 }. The
format of the string is as follows:
YYYYMMDDHHmmssZ
Where:
YYYY - is the 4 digits representation of the year
MM - is the 2 digits representation of the month
DD - is the 2 digits representation of the day of the month
HH - is the 2 digits representation of the hour of the day (24
hour format)
mm - is the 2 digits representation of the minutes of the hour
ss - is the 2 digits representation of the seconds of the
minute
Z - is the character 'Z'
ExpiresOn (16 octets)
This field carries the GMT date for when this credential is to be
considered expired. This field is 16 bytes long (the last byte
must be set to '0x00') and contains the NULL-terminated ASCII
string that represents the timestamp where the credential was
issued. The format is the same as the ('IssuedOn') field. When
the value is not set, the field should be set to { 0x00 }.
Credentials Length (uint16)
Length (in bytes) of the Credentials value. When used with a
public-key type of credentials, this is the size of the key (e.g.,
for an RSA 2048 bit keys, this field should carry the value of
256). When used with a symmetric secret, this field carries the
size of the secred (in bytes).
CredIDValue (> 1 octet)
The binary value of the credentials' identifier. This identifier
can be the binary value of the SHA-256 calculated over the
certificate, a username, or it could be a random handle. As long
as the ID allows the peer and the server to uniquely (in its
context) identify the credentials, the value of this field can be
calculated in any way.
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4.3.6. The Credentials-Data TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cred Type | Format | Encoding | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Credentials-Data TLV
Length (uint24)
Provides the length of the TLV (> 3 octets)
Cred Type (uint8)
Provides the indication of the type of credentials. The allowed
values for this field are listed in Section 8.3.
Format (uint8)
Provides the indication of the Format the credentials are in. The
allowed values for this field are listed in Section 8.5.
Encoding (uint8)
Provides the indication of the Encoding the credentials are in.
The allowed values for this field are listed in Section 8.8.
Value (octet string)
This field carries the data for the credentials.
4.3.7. The Error TLV
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EAP-CREDS Error Code | Secondary Error Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Description ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Challenge-Response-Data TLV
Length (uint24)
3 octets
EAP-CREDS Error Code (2 octets)
This field carries the EAP-CREDS error code. These code are
related to the EAP-CREDS operations only and it should not be used
to carry the Provisioning-Protocol specific error codes.
The error codes supported by this specifications are listed in
Section 4.3.7.
Secondary Error Code (2 octets)
This field is used to convery an error at the encapsulation layer
(i.e., the provisioning protocol error). For example, this field
can be used to convey a transport protocol error code (e.g., HTTP
status code). Do not use this field to convery EAP-CREDS specific
errors.
Description ( > 1 octet)
The Description field is optional (i.e., when the Description Size
is set to zero) and carries information about the error that
occurred. The message may or may not be used by a user or an
automated process for debugging purposes.
4.3.8. The Network-Usage TLV
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U| Desc Format | Encoding | Network-Usage Data ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Network-Usage TLV
Length (uint24)
Variable Length TLV (Value must be > 2 )
Description Format (uint8)
The Type of data encoded in the Peer Description Data. The
initial values for this field are listed in Section 8.10.
Encoding (uint8)
Provides the indication of the Encoding the network usage
description data is in. The allowed values for this field are
listed in Section 8.8.
The 'U' field (1 bit)
The 'URL' bit ('U') is used to indicate if the value of the
Network-Usage Data field is to be interpreted as a URL or as the
actual data. In particular, if the value in the 'URL' bit is '1',
then the value in the Network-Usage Data field is to be
interpreted as the URL where the actual data can be downloaded
from. Otherwise, if the 'URL' bit is set to '0', then the value
in the Netowrk-Usage Data field is to be interpreted as the actual
data (not a URL referencing it).
An example use of this bit is when the Peer wants to convey the
URL of the MUD file [RFC8520]. In this case, the Peer can set the
Network-Usage Data field to the Url of the MUD file related to the
Peer.
Desc Format (7 bits)
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This field provide the expected data format for the Network-Usage
Data. For example, the value in this field could be set to 'MUD'
and have the 'U' bit set to '1' to provide the MUD-related
information at credentials management time instead of at network-
provisioning time (DHCP option). This possibility could help the
Network controller to decide if the device shall be allowed to
register its credentials or not.
The list of initial values for this field is provided in
Section 8.7.
Network-Usage Data (octet string)
This is additional information related to the device. In
particular, this TLV can be used by the Peer to provide the Server
with the description of the intended network usage or a URL that
points to the same information.
For example, this field can be used to convey a MUD file
(Manufacturer Usage Description) or the latest firmware-update
manifest.
4.3.9. The Profile TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Profile Identifying Data ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Profile Identifying Data TLV
Length (uint24)
Length value should be >= 1
Profile Identifying Data (octet string)
The Profile Identifying Data is used to provide indication to the
other party about which profiles are supported when requesting
credentials management.
Also in this case, the data used in this field is left to be
interpreted by the end-point and it is orthogonal to EAP-CREDS
data types.
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An example of values for this field, an end-point could use the
string representation (i.e., dotted representation) of the Object
Identifier (OID) of the specific profile supported (e.g., could be
defined in the Certificate Policy of the credentials' provider).
4.3.10. The Protocol TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol ID | Version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Protocol TLV
TLV Length (uint24)
Fixed TLV Length value of 4.
Protocol ID (uint16)
The Protocol ID value carries the id of a supported provisioning
protocol. The initial list of values for the provisioning
protocol identifiers can be found in Section 8.1.
Version (uint16)
The Version (Protocol Version) value represents the specific
version of the identified provisioning protocol. When no version
is specified for a protocol (i.e., either it does not support
multiple versions or it does not matter), the value of this field
should be set to '0x0'.
4.3.11. The Provisioning-Data TLV
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Provisioning Data ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Provisioning-Data TLV
Length (uint24)
3 octets
Headers Data (> 1 octet)
This field carries the provisioning protocol's messages.
4.3.12. The Provisioning-Headers TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Headers Data ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Provisioning-Headers TLV
Length (uint24)
3 octets
Headers Data (> 1 octet)
This field carries the meta-data (if any) that might be associated
with the transport-layer normally used with the provisioning
protocol. For example, this TLV can carry the set of HTTP headers
required by EST or ACME.
4.3.13. The Provisioning-Params TLV
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Min Length | Max Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Algorithm | Flags | OBJECT IDENTIFIER (DER) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Provisioning-Params TLV
Length (uint24)
Provides the length of the TLV (>= 6 octets)
Min Length (uint16)
Provides the minimum allowed size size for the credentials. This
value has meaning depending on the context of the credentials,
however sizes are always expressed in bytes.
For example, when used with a symmetric key or a password, the
('Min Length') and ('Max Length') refer to the minimum and maximum
size of the password data. The ('Algor OID') field can be omitted
in this case.
On the other hand, when referring public-key credentials, this
field should carry the size of the modulus of the key. For
example, for an RSA 2048 bit keys, the field should carry the
value of 256. For an ECDSA that uses the prime256r1 curve, this
field should carry the value of 32 and the Algor OID should be the
DER representation of the specific value of the curve (i.e., the
DER representation of '1.2.840.10045.3.1.7').
Max Length (uint16)
Provides the indication maximum size of the credentials. This
value has meaning depending on the context of the credentials,
however sizes are always expressed in bytes.
The same considerations apply to this field as well as the ('Min
Length') one discussed above.
Flags (uint8)
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Provides a BITMASK that can be used to provide information about
the status of the credentials (e.g., if the use marks the
credentials to be compromised). The bits have the following
meaning:
Bit 0 - Credentials (or part of it) are to be generated on the
server
Bit 1 - Credentials (or part of it) are to be generated on the
peer
Bit 2 - Credentials are to be generated on dedicated hardware
Bit 3 - Reserved
Bit 4 - Reserved
Bit 5 - Reserved
Bit 6 - Reserved
Bit 7 - Reserved
When using public-key based credentials, the bits 0 and 1 are
mutually exclusive.
When using passwords or shared secrets, if bit 0 is set, then the
secret is generated by the server and then sent to the client. On
the other hand, if bit 1 is set, then the secret is generated by
the peer and then sent to the server. Ultimately, if both bits
are set, then the Server generates the first part of the password
and sends it to the Peer, while the Peer generates the second part
of the password and sends it to the Server. The password to be
used for future authentication is the concatenation of the two
shares of the password: first the one from the Server, then the
one from the Client.
NOTE WELL: Last but not least, since these passwords/secrets are
meant to be used in a automated fashion, there is no restriction
around the character set to use or their interpretation.
Therefore,it is good practice to generate random passphrases that
use the full 8-bit character set (on client and server) to
maximize the secret's search space.
Algorithm (uint8)
Provides the indication of the algorithm used for the generation
of the credentials. The allowed values for this field are listed
in Section 8.4.
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Object Identifier (binary; > 1 octet)
Provides the indication of additional parameters that are needed
to be encoded for the credentials. This value is used only when
the credentials use public-key cryptography - this field carries
additional information about the generation algorithm to be used.
We provide some useful values that can be used as reference:
+===============+=======================+=========================+
| OID Name | Dotted Representation | Binary Encoding |
+===============+=======================+=========================+
| secp256r1 | 1.2.840.10045.3.1.7 | 06 08 2A 86 48 CE 3D 03 |
+---------------+-----------------------+-------------------------+
| curve | | 01 07 |
+---------------+-----------------------+-------------------------+
| secp384r1 | 1.2.840.10045.3.1.34 | 06 08 2A 86 48 CE 3D 03 |
+---------------+-----------------------+-------------------------+
| curve | | 01 22 |
+---------------+-----------------------+-------------------------+
| secp521r1 | 1.2.840.10045.3.1.35 | 06 08 2A 86 48 CE 3D 03 |
+---------------+-----------------------+-------------------------+
| curve | | 01 23 |
+---------------+-----------------------+-------------------------+
| X25519 curve | 1.3.101.110 | 06 03 2B 65 6E |
+---------------+-----------------------+-------------------------+
| X25519 curve | 1.3.101.110 | 06 03 2B 65 6E |
+---------------+-----------------------+-------------------------+
| X448 curve | 1.3.101.111 | 06 03 2B 65 6F |
+---------------+-----------------------+-------------------------+
| Ed25519 curve | 1.3.101.112 | 06 03 2B 65 70 |
+---------------+-----------------------+-------------------------+
| Ed448 curve | 1.3.101.113 | 06 03 2B 65 71 |
+---------------+-----------------------+-------------------------+
Table 2: Object Identifiers Examples
4.3.14. The Certificate-Request TLV
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Encoding | Format | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Token-Data TLV
TLV Length (uint24)
Provides the length of the TLV (> 3 octets)
Encoding (uint8)
Provides the indication of the Encoding the credentials are in.
The allowed values for this field are listed in Section 8.8.
Format (uint8)
Provides the indication of the type of credentials. The allowed
values for this field are listed in Section 8.5.
Value (octet string)
This field carries the data for the credentials.
4.3.15. The Storage-Info TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | Flags | Spare Slots |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available Memory |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Store-Info TLV
Flags (8 bits)
Provides information about the status and type of store and
limited information about its capabilities. The bits have the
following meaning:
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Bit 0 - If set, the store supports RSA keys (software)
Bit 1 - If set, the store supports RSA keys (hardware) Bit 2 -
If set, the store supports ECDSA keys (software)
Bit 3 - If set, the store supports ECDSA keys (hardware)
Bit 4 - If set, the store supports symmetric keys
Bit 5 - If set, the store supports generic tokens
Bit 6 - If set, the store is immutable (no key generation or
deletion)
Bit 7 - Not Used
Spare Slots (uint16)
Provides the number of available slots where to store credentials.
When no more slots are available, the value of '0' should be used
to indicate to the Server that a credential must be deleted before
a new one can be created.
When the number of slots is not fixed or not known, the value of {
0xFF, 0xFF } shall be used.
Available Memory (uint32)
This field carries the size (in bytes) of the spare memory on the
Peer's secrets' store.
4.3.16. The Formats TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Format |
+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Supported-Format TLV
TLV Length (uint24)
Provides the length of the TLV. This field must be set to 1.
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Format (uint8)
Provides the details about the supported format. Multiple formats
TLVs can be used in the Peer's ('Init') message to provide the
Server with the Peer's capabilities.
4.3.17. The Supported-Encoding TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Encoding |
+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Store-Info TLV
TLV Length (uint24)
Provides the length of the TLV. The field has a fixed value of 1.
Encoding (uint8)
Provides the indication of the supported Encoding by the End
Point. This provides the indication to the Server of the
capability of the Peer. The allowed values for this field are
listed in Section 8.8.
4.3.18. The Token-Data TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Token Type | Encoding | Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Token-Data TLV
TLV Length (uint24)
Provides the length of the TLV (> 3 octets)
Token Type (uint8)
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Provides the indication of the type of credentials. The allowed
values for this field are listed in Section 8.2.
Encoding (uint8)
Provides the indication of the Encoding the credentials are in.
The allowed values for this field are listed in Section 8.8.
Value (octet string)
This field carries the data for the credentials.
4.3.19. The Version TLV
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version |
+-+-+-+-+-+-+-+-+
TLV Type (uint8)
<TBD> - Version TLV
TLV Length (uint24)
Provides the length of the TLV. The field has a fixed value of 1.
Version (uint8)
The Version field represents the specific version of the EAP-CREDS
protocol that are supported by the end point. When multiple
versions of EAP-CREDS are supported, multiple ('Version') TLVs can
be used.
When no version is specified (i.e., either it does not support
multiple versions or it does not matter), the value of this field
should be set to '0x0' (any version).
5. EAP-CREDS Messages
This section describes each message and what TLVs are allowed or
required. EAP-CREDS defines the following values for the Message
Type (Type):
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+==============+========================+===========================+
| Message Type | Name | Description |
+==============+========================+===========================+
| 0 | EAP-CREDS-Init | Initialization Phase |
+--------------+------------------------+---------------------------+
| 1 | EAP-CREDS-Provisioning | Carries Provisioning |
+--------------+------------------------+---------------------------+
| | | Protocol Messages |
+--------------+------------------------+---------------------------+
| 2 | EAP-CREDS-Validate | Validates newly |
| | | installed |
+--------------+------------------------+---------------------------+
| | | credentials |
+--------------+------------------------+---------------------------+
Table 3: EAP-CREDS Message Types
5.1. The EAP-CREDS-Init Message
The EAP-CREDS-Init message type is used in Phase One only of EAP-
CREDS. The message flow is depicted in Section 3.3. This message
supports the following TLVs: Version, Protocol, Credentials-Info, and
Error.
5.1.1. EAP Server's Init Message
EAP-CREDS starts with an ('EAP-CREDS-Init') message from the server.
This message MAY contain zero, one, or more ('Version') TLVs and,
optionally, a ('Challenge-Data') TLV.
The first message from the server is the one that starts Phase One,
therefore the Server MUST set the headers' 'S' bit to '1' (Start) and
the headers' 'Phase' value to '0x01' (Phase One).
The Server uses one or more ('Version') TLVs in the EAP-Request/EAP-
CREDS(Type=Init) message to provide the Peer with the list of EAP-
CREDS versions supported. If omitted, the implict version of EAP-
CREDS used in the session is one ('0x1'). If the Server detects
multiple occurrences of this TLV in the reply from the Peer, an error
shall be issued and the EAP-CREDS session should be terminated.
In case Token-Based registration is enabled on the Server, the Server
MUST include, in its Init message, a ('Challenge-Data') field that
can be used by the client to provide challenge data for proof-of-
possession of secrets.
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5.1.2. EAP Peer's Init Message
The Peer MUST reply to the Server's ('EAP-CREDS-Init') message with
its own ('EAP-CREDS-Init') one. The Peer SHOULD include one
('Version') TLV in its first message to indicate the version of EAP-
CREDS that the client wants to use for the session. The Peer MUST
also provide the list of supported provisioning protocols (via one or
more the 'Protocol' TLV), the list and status of the installed
credentials (via the 'Credentials-Info' TLV). The Peer MAY include
authorization data when registering new credentials (e.g., an
authorization token or a device certifcate) via the ('Token-Data')
and ('Challenge-Response') TLV.
The Peer MUST include one ('Credentials-Info') TLV for each
credential the Network is authorized to manage. Typically, a Peer
will include only one ('Credentials-Info') TLV in its ('EAP-CREDS-
Init') message, but there might be cases where multiple types of
credentials are available and selected depending on the location and
other factors (e.g., X.509 certificate and username/password
combination).
In case the Peer does not have any credentials available yet, it does
not add any ('Credentials-Info') TLV - leaving the Server with the
only action possible: Registration. In this case, the Peer SHOULD
include authorization information via the ('Token-Data') TLV as
described in Section 5.1.2.1. Additionally, the Peer can add the
('Profile') TLV to indicate a preferred profile for the credentials.
5.1.2.1. Bootstrapping Peer's Trustworthiness
When the Peer does not have any valid credentials for the Network
that it is authenticating to, it does not provide any ('Credentials-
Info') TLV. This indicates to the Server that new credentials MUST
be registered before the Peer is allowed on the network.
The Registration process might rely on information exchanged during
the Provisioning Process in Phase Two. However, if an authorization
mechanism is not available from the supported provisioning protocol
and no credentials are available on the Peer, EAP-CREDS provides a
simple machanism for the Peer to leverage an out-of-band
token/passphrase/ott that may be already available on the Peer (e.g.,
a device certificate or a 'spendable' credentials token like a
kerberos ticket or a crypto-currency transaction) and that can be
verified by the Server.
In particular, when the Peer wants to register new credentials (and
the Server requires the use of additional authorization data) it may
need to provide (a) a Token, (b) a challenge value, and (c) a
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response to the challenge value. To do so, the Peer MUST encode the
token in a ('Token-Data') TLV, the challenge value in a ('Challenge-
Data') TLV, and, finally, the response to the challenge in the
('Challenge-Response') TLV.
The use of ('Challenge-Data') and ('Challenge-Response') TLVs is
optional, however it is suggested that if a token is used for
bootstrapping the trust, it should provide a way to verify a secret
associated with it.
It is also very important that the authorization token is disclosed
only to authorized servers - the Peer MUST NOT disclose authorization
tokens that are not meant for the network that is being accessed.
This can be done, usually, by verifying the identity of the Server
first (in the outer mechanism) and then verify that the target of the
Token is the Server the Client is talking to.
5.1.3. The EAP-CREDS-Provisioning Message
The EAP-CREDS-Provisioning message type is used in Phase Two only of
EAP-CREDS. The message flow is depicted in Section 3.4. This
message type supports the following TLVs: Protocol, Profile,
Credentials-Info, Provisioning-Headers, Provisioning-Data, Token-
Data, and Error.
After the exchange of Phase One messages, the Server MAY start phase
two by issuing an ('EAP-CREDS-Provisioning') message for the Peer
where it encodes all the required details for starting the
provisioning process. In particular, the server sends the selected
('Action'), ('Protocol'), and metadata to the client in a EAP-
Request/EAP-CREDS(Type=Provisioning) message. The header's 'S' bit
MUST be set to '1' (Start) and the 'Phase' value set to '0x02' (Phase
Two begins).
NOTE WELL: After the initial message, the only TLVs that are
allowed in messages coming from the server are the usual
('Provisioning-Headers') ('Provisioning-Data'), and ('Error').
The client checks that all the selected parameters are supported for
the selected credentials and, if no errors are detected, it sends its
first ('EAP-CREDS-Provisioning') message to the Server with the
('Provisioning-Headers') and ('Provisioning-Data') TLVs only.
From now on, the conversation between the Peer and the Server
continues until an error is detected or the provisioning protocol
completes successfully.
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If no other actions, the server MAY continue with phase three or
issue a success message and terminate the EAP session.
NOTE WELL: When the SPP protocol is used, the protocol messages
that are encoded inside the ('Protocol-Data') TLV are composed of
sets of TLVs as defined in this document. The overall message
size is provided by the size of the ('Protocol-Data') TLV that
encapsulates the SPP-specific TLVs. This design choice provides
symmetry in implementing support for SPP when compared to other
provisioning protocols.
5.1.4. The EAP-CREDS-Validate Message
The EAP-CREDS-Validate message type is used in Phase Three only of
EAP-CREDS. The message flow is depicted in Section 3.5. This
message type supports the following TLVs: Protocol, Credentials-Info,
Provisioning-Headers, Provisioning-Data, Token-Data, and Error.
After Phase One (and/or Phase Two) ends, the Server MAY start phase
three by issuing an ('EAP-CREDS-Validate') message for the Peer where
it encodes all the required details for starting the validation
process. In particular, the server sends the ('Credentials-Info'), a
('Challenge-Data'), in a EAP-Request/EAP-CREDS(Type=Validate)
message. The 'S' bit (Start) should set the '1' for its value and
the 'Phase' field sets to '0x03' (Phase Three starts).
The Peer generates the answer to the Challenge and sends back a EAP-
Response/EAP-CREDS(Type=Validate) message with the ('Challenge-
Response') and an optional ('Challenge') field (only for server-side
validation of the symmetric credentials). If the Peer requested
server-side validation of the credentials, the Server MUST include
(if a symmetric secret) the response to the Peer-issued ('Challenge-
Data') TLV by computing the response and adding it to the
('Challenge-Response') TLV in its reply.
Finally, in the last message, the Server (if Phase Three is to be
ended) SHALL set the 'S' bit to '0' (end of phase) and the value of
'Phase' field set to '0x03'.
At this point, EAP-CREDS has terminated all possible operations and
can be terminated. The Server can now terminate the EAP session
successfully. In case the Peer was not authenticated during the
tunnel establishment (i.e., no credentials were already available on
the Peer), the Server should terminate the EAP session with a Failure
(thus requiring the device to re-attach and authenticate to the
network - phase two should have provided the Peer with the
credentials to use for authenticating to the Network).
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6. Error Handling in EAP-CREDS
This section provides a description of the error handling by using
the CREDS-Error-TLV in a CREDS message.
7. The Simple Provisioning Protocol (SPP)
EAP-CREDS supports a Simple Provisioning Protocol (SPP) which
comprises of a series of messages that enable the management not only
of certificates, but also of other types of credentials like
username/password pairs, asymmetric keys, and symmetric keys.
The Simple Provisioning Protocol (SPP), described in this section,
behaves as any other provisioning protocol: its messages are
encapsulated in the ('Provisioning-Data') TLVs in the second phase of
the protocol. SPP does not make use of any ('Provisioning-Headers')
TLVs because its messages are all self-contained (no transport-
protocol specific options are needed).
When no ('Credentials-Info') TLVs have been provided by the client,
the Server knows that the device does not have valid credentials it
wants to use to access the Network. In this case, EAP-CREDS/SPP
supports the use of Tokens to kick-off the registration process. The
type, format, or encoding of the Token is orthogonal to EAP-CREDS/SPP
which treats the token as a black-box field (i.e., it SHOULD NOT try
to interpret or parse its contents).
NOTE WELL: During Phase One, the Peer MAY include the ('Token-
Data') TLV in its EAP-CREDS-Init message to provide the needed
authorization to register a new set of credentials. The Server
might not allow the registration of new credentials if the
required authorization (i.e., the Token) was not provided during
the initialization phase.
In the case where an authorization token is used, different usage
patterns are supported. For tokens that require an associated
verifiable proof-of-possession, the Peer can include a ('Challenge-
Response') TLVs.
The ('Challenge-Data') TLV provided by the Server MUST be used to
convey the challenge data (usually some random value) to compute the
contents of the ('Challenge-Response') TLV.
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The ('Challenge-Response') TLV is used, instead, to encode the
response to the challenge data. The ('Challenge-Response') TLV is
generated by the Peer and verified by the Server. At minimum, the
('Challenge-Response') TLV SHOULD be calculated over the values of
the ('Token-Data') and the ('Challenge-Data') TLVs to make sure that
the authentication covers the token's data as well.
NOTE WELL: The use of the ('Token-Data'), ('Challenge-Data'), and
('Challenge-Response') TLVs in the Peer's Init message is be used
only to bootstrap trust between the Server and the Peer. If the
Server accepts the authorization information as valid, the Peer is
enabled for registering new credentials. This should happen only
when the Peer does not have valid credentials or when the server
wants to provision a different type of credentials (i.e.,
Action=(Register)). Other methods to provide authorization
information might be provided by the selected provisioning
protocol: in this case, the Server MAY enable registration of new
credentials when no authorization data is provided in the 'Init'
message from the client and delegate the validation of the
authorization data during Phase Two.
7.1. SPP Message Format
The SPP Messages are constructed with zero, one, or more TLVs and
encoded in the ('Provisioning-Data') TLV in EAP-CREDS/Provisioning
message types. The size of the encpasulating ('Provisioning-Data')
TLV provides the size of the whole message.
7.2. SPP Message Flow
,--------. ,----------.
|EAP Peer| |EAP Server|
`---+----' `----+-----'
| [1] EAP-Request/EAP-CREDS(Type=Provisioning) |
| { Protocol(=SPP), Action, |
| [ CredsInfo ] [ Params ], |
| [ ProvData(=CredsData) ] } |
| <------------------------------------------
| |
| [2] EAP-Response/EAP-CREDS(Type=Provisioning)|
| { [ ProvData(=CredsData) ] } |
| ------------------------------------------>
| |
| [3] EAP-Response/EAP-CREDS(Type=Provisioning)|
| { [ ProvData(=CredsData) ] } |
| <------------------------------------------
| |
| |
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SPP was designed to provide an easy alternative to more complex
provisioning protocols. When no extra flexibility is needed, SPP
provides an easy-to-implement alternative that can handle not only
certificates, but also symmetric secrets and access tokens
provisioning. In this section we provide the generic flow of
messages for SPP and specific examples for certificates, username/
password, and token provisioning.
EAP-CREDS defines several actions for a set of credentials and they
are listed in Section 8.9.
When a Peer wants to join a network it may or may not have have the
needed credentials to do so. In case the Peer does not have valid
credentials yet, the Server MAY start Phase Two with the intention of
registering a new set of credentials. Alternatively, the Server MAY
start Phase Two when the presented credentials information from the
Peer triggers the Renew or the Remove action.
[1] The Server sends EAP-Request/EAP-CREDS(Type=Provisioning)
When registering new credentials, the first message from the
Server, MUST not carry a ('Credentials-Info') TLV since there is
no targeted credentials to apply the action on (i.e., for other
actions - like 'renew' or 'remove' - the TLV would be required to
identify the right set of credentials to renew or delete).
In SPP, the Server sets the ('Protocol') TLV to SPP, the
('Action') TLV to 'Register', 'Renew', or 'Remove'. When
provisioning (or registering) new credentials for the Peer, the
Server also sets the ('Provisioning-Params') TLV (or Params) to
the type of credentials to be provisioned. The Server also sets
any relevant constraints, and, optionally, the ('Profile') TLV.
NOTE WELL: If the Peer is authorized to register a new set of
credentials, then the first message from the Server will have the
('Action') TLV set to 'register' and no ('Credentials- Info') TLV
is present in the Server's message. In case server- side
generation is used, an additional ('Credentials-Info') TLV MAY be
encoded inside the ('Provisioning-Data') TLV.
If the type of credentials is symmetric and the parameters call
for server-side generation of a symmetric key share, the Server
MUST also include its own generated share in a ('Credentials-
Data') TLV inside the ('Provisioning-Data') one (the data for the
provisioning protocol are encapsulated in the 'Provisioning-Data'
TLV for any protocol used during Phase Two - SPP is no exception
to this rule).
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In case Server-side only is selected, the Server MUST send the new
credentials in its message and include the ('Credentials-Info')
TLV. If no other credentials need to be managed, the Server MUST
end Phase Two by setting the appropriate bits in the EAP-CREDS
headers as well.
[2] The Peer sends EAP-Response/EAP-CREDS(Type=Provisioning)
When Peer-generation is selected (either Peer-only or combined
Peer and Server side) and Phase Two has not terminated yet, the
Peer MUST reply to the Server's message with its own
'Provisioning' response. The response MUST carry either (a) its
own generated share of the key in a ('Credentials-Data') TLV (if
the credentials that are provisioned are symmetric and the
configuration calls for a share of the key to be provided by the
Peer) or (b) a PKCS#10 request in a ('Certificate-Request') TLV
(also in this case, only if client-side generation was enabled by
the Server) that is generated by using the parameters provided by
the Server in the ('Provisioning-Params') TLV.
[3] The Server sends EAP-Request/EAP-CREDS(Type=Provisioning)
The last message of SPP is from the Server and it is used to
deliver the finalized value of the credentials and/or associated
metadata. In case the credentials being provisioned are
Certificate-based, the Server MUST include the issued certificate
in its reply. The issued credentials shall be encoded in a
('Credentials-Data') TLV inside the ('Provisioning-Data') one. In
case that the selected format supported/selected by the Peer and
the Server does not provide the possibility to encode the full
chain (i.e., intermediate and Root CAs) in the response, the
Server MUST add one ('Certificate-Data') TLV for each certificate
in the chain (including the Root CA's certificate).
The Server MUST include the ('Credentials-Info') TLV in its
message. This provide the Peer with some additional data (e.g.,
the 'Profile' or the 'Identifier' associated with the credentials
that were provisioned/managed).
In the case where additional credentials need to be managed, the
Server can continue Phase Two by issuing a new [1] message where
the tuple Action/Credentials must be unique for the current EAP-
CREDS session.
The Server can now decide to start Phase Three (suggested if new
credentials were provisioned or renewed) or to terminate the EAP
session successfully.
7.2.1. SPP Symmetric Secrets Management
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,--------. ,----------.
|EAP Peer| |EAP Server|
`---+----' `----+-----'
| [1] EAP-Request/EAP-CREDS(Type=Provisioning) |
| { Protocol(=SPP), Action, [ Creds-Info ], |
| [ Prov-Params ], [ Profile ] |
| [ Prov-Data(=[Creds-Info],[Creds-Data]) ] }|
| <-----------------------------------------------
| |
| [2] EAP-Response/EAP-CREDS(Type=Provisioning) |
| { [ Prov-Data(=[Creds-Data]) ] } |
| ----------------------------------------------->
| |
| [3] EAP-Response/EAP-CREDS(Type=Provisioning) |
| { [ Prov-Data(=Creds-Info,[Creds-Data]) ] } |
| <-----------------------------------------------
| |
| |
EAP-CREDS/SPP can provision symmetric secrets (e.g, username/
password, API keys, or SIM-based keys), tokens (e.g., username/
password OAuth or Kerberos tokens), or asymmetric credentials (e.g.,
X.509 certificates or Key Pairs). This section focuses on
provisioning symmetric secrets only. The message flow is provided in
Section 7.2.1
EAP-CREDS/SPP provides the possibility for shared secret to be
generated in different ways:
1. Server-Side Generated
2. Client-Side Generated
3. Both Client-Side and Server-Side Generated
In particular, when initiating the second phase of the protocol, the
('Provisioning-Params') TLV is used to specify how to generate the
secret (see Section 4.3.13).
7.2.1.1. Server Side Only Generation
[ TO BE EDITED ]
Figure 1: SPP Message Flow for Server-Side only secrets provisioning
The message flow for deploying a server-side only credential (i.e.,
during registration or renewal) consists of only one message from the
server. The flow is depicted in Figure 1.
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In this case, the Server sends the first Provisioning message (which
is also the last one), which MUST carry, the following data:
* The ('Credentials-Info') TLV that specifies the info for the
provisioned secret, and
* The ('Protocol') TLV that specifies the provisioning protocol to
be used, and
* The ('Action') TLV that provides the action to be performed
('Registration') or ('Renew'), and
* The ('Provisioning-Params') TLV that provides the generation
parameters to the Peer, and
The Server also includes, encoded in the ('Provisioning-Data') TLV,
the following data:
The ('Credentials-Info') TLV that provides the metadata associated
with teh generated secret
The ('Credentials-Data') TLV that provides the secret that is
provisioned to the Peer
Server-side secrets' generation can be used to generate username/
password combinations, API Keys, SIM-based credentials, or tokens.
7.2.1.2. Client Side Only Generation
[ TO BE EDITED ]
Figure 2: SPP Message Flow for Client-Side only secrets provisioning
The message flow for deploying a client-side only credential (i.e.,
during registration or renewal) consists of the full three messages
exchange. The flow is depicted in Figure 2.
In this case, the Server MUST include, in its first Provisioning
message and encoded in the ('Provisioning-Data') TLV, the following
data:
* The ('Credentials-Info') TLV that specifies the target
credentials, and
* The ('Protocol') TLV that specifies the provisioning protocol to
be used, and
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* The ('Action') TLV that provides the action to be performed
('Registration') or ('Renew'), and
* The ('Provisioning-Params') TLV that provides the generation
parameters to the Peer, and
Notice that the Server does not include any ('Credentials-Data') TLV
in its first message because the Server is not involved in the secret
generation (client-side only).
The Peer MUST reply with its own Provisioning message where the Peer
MUST encode the following data in the ('Provisioning-Data') TLV:
The ('Credentials-Data') TLV that provides the secret that is
being registered
The credentials data MUST conform to the specifications the Server
provided in the ('Provisioning-Params') TLV.
The final message is from the Server and it MUST contain (if no
errors were detected), the following TLVs encoded, as usual, in the
('Provisioning-Data') TLV:
The ('Credentials-Info') TLV that specifies the metadata
associated with the generated secret, and
The ('Credentials-Data') TLV that provides the secret that is
provisioned to the Peer
Client-side secrets' generation should be used with caution and an
evaluation of the quality of the generated credentials MUST be
performed to make sure that the security of the generated secret is
adequate for accessing the network. Since evaluating the quality of
a secret is quite a difficult tasks, the use of this generation mode
MUST be evaluated carefully and selected accordingly to acceptable
risk profiles.
7.2.1.3. Client and Server Side Generation
When registering or renewing credentials and the secret generation is
split between the Server (1st share) and the Peer (2nd share), the
message flow is the same as Section 7.2.1.2 with the following
exceptions:
* The Server MUST send its own share of the secret by including a
('Credentials-Data') TLV in its first message.
All other parameters remain the same.
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Co-generation of the secret is the most secure option because both
parties can provide the required randomness in their own share of the
secret.
7.2.2. SPP Key Pair Provisioning
EAP-CREDS/SSP defines the following flow of messages for requesting
the provisioning of key pairs (public and private keys).
7.2.2.1. Server Side Only Generation
[ This case covers the server-side generation of KeyPair and
Certificate ]
7.2.2.2. Client Side Only Generation
[ This case covers the registration of a self-signed or already
available (e.g., device) certificate ]
7.2.2.3. Client and Server Side Generation
This use-case is not supported. In other words, for the provisioning
of Key Pairs, the ('Provisioning-Params') can not have both the peer-
generation and server-generation bits set.
7.2.3. SPP Certificate Provisioning
EAP-CREDS/SSP defines the following flow of messages for requesting
the provisioning of credentials.
7.2.3.1. Server Side Only Generation
[ This case covers the server-side generation of KeyPair and
Certificate ]
7.2.3.2. Client Side Only Generation
[ This case covers the registration of a self-signed or already
available (e.g., device) certificate ]
7.2.3.3. Client and Server Side Generation
[ This case covers the generation of the KeyPair on the Peer and the
generation of the certificate on the Server ]
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7.2.4. SPP Token Provisioning
EAP-CREDS/SSP defines the following flow of messages for requesting
the provisioning of token-based credentials.
7.2.4.1. Server Side Only Generation
[ This case covers the server-side generation of the Token and
possibly associated key ]
7.2.4.2. Client Side Only Generation
[ This case covers the registration of a self-signed or already
available (e.g., device) certificate ]
7.2.4.3. Client and Server Side Generation
[ This case covers the generation of the KeyPair on the Peer and the
generation of the Token that cointains the reference to the key on
the Server ]
8. IANA Considerations
This document uses a new EAP type, EAP-CREDS, whose value (TBD) MUST
be allocated by IANA from the EAP TYPEs subregistry of the RADIUS
registry. This section provides guidance to the Internet Assigned
Numbers Authority (IANA) regarding registration of values related to
the EAP-CREDS protocol, in accordance with [RFC8126].
The EAP Method Type number for EAP-CREDS needs to be assigned.
This document also requires IANA to create new registries as defined
in the following subsections.
8.1. Provisioning Protocols
+=================+===============================================+
| Message Type | Purpose |
+=================+===============================================+
| 0 | Unspecified |
+-----------------+-----------------------------------------------+
| 1 | Simple Provisioning Protocol (SPP) |
+-----------------+-----------------------------------------------+
| 2 | Basic Certificate Management Protocol (CMP-S) |
+-----------------+-----------------------------------------------+
| 3 | Full Certificate Management Protocol (CMP-F) |
+-----------------+-----------------------------------------------+
| 4 | Enrollment over Secure Transport (EST) |
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+-----------------+-----------------------------------------------+
| 5 | Certificate Management over CMS (CMC) |
+-----------------+-----------------------------------------------+
| 6 | Automatic Certificate Management Environment |
+-----------------+-----------------------------------------------+
| | (ACME) |
+-----------------+-----------------------------------------------+
| ... | ... |
+-----------------+-----------------------------------------------+
| 49141 ... 65534 | Vendor Specific |
+-----------------+-----------------------------------------------+
Table 4: EAP-CREDS Inner Protocol Identifiers
Assignment of new values for new cryptosuites MUST be done through
IANA with "Specification Required" and "IESG Approval" as defined in
[RFC8126].
8.2. Token Types
+============+=================+
| Token Type | Description |
+============+=================+
| 0 | Unspecified |
+------------+-----------------+
| 1 | JWT |
+------------+-----------------+
| 2 | Kerberos |
+------------+-----------------+
| 3 | OAuth |
+------------+-----------------+
| 4 | Certificate |
+------------+-----------------+
| 200..254 | Vendor Specific |
+------------+-----------------+
Table 5: Token Types
Assignment of new values for new Message Types MUST be done through
IANA with "Expert Review" as defined in [RFC8126].
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8.3. Credentials Types
+==================+=======================+
| Credentials Type | Description |
+==================+=======================+
| 0 | X.509 Certificate |
+------------------+-----------------------+
| 1 | Public Key |
+------------------+-----------------------+
| 2 | Symmetric Key |
+------------------+-----------------------+
| 3 | Username and Password |
+------------------+-----------------------+
| 4 | AKA Subscriber Key |
+------------------+-----------------------+
| 5 | Bearer Token |
+------------------+-----------------------+
| 6 | One-Time Token |
+------------------+-----------------------+
| 7 | API Key |
+------------------+-----------------------+
Table 6: Credentials Types
Assignment of new values for new Message Types MUST be done through
IANA with "Expert Review" as defined in [RFC8126].
8.4. Credentials Algorithms
+=========+====================+
| ID | Algorithm |
+=========+====================+
| 0 | None |
+---------+--------------------+
| 1 | RSA |
+---------+--------------------+
| 2 | ECDSA |
+---------+--------------------+
| 3 | XMMS |
+---------+--------------------+
| 4 | AKA Subscriber Key |
+---------+--------------------+
| 5 | OAuth |
+---------+--------------------+
| 6 | Kerberos4 |
+---------+--------------------+
| 7 | Kerberos5 |
+---------+--------------------+
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| 200-254 | Reserved |
+---------+--------------------+
Table 7: Credentials Algorithms
Assignment of new values for new Message Types MUST be done through
IANA with "Expert Review" as defined in [RFC8126].
8.5. Credentials Datatypes
+=========+===============+
| ID | Data Type |
+=========+===============+
| 0 | None (Binary) |
+---------+---------------+
| 1 | PKCS#8 |
+---------+---------------+
| 2 | PKCS#10 |
+---------+---------------+
| 3 | PKCS#12 |
+---------+---------------+
| 4 | PublicKeyInfo |
+---------+---------------+
| 200-254 | Reserved |
+---------+---------------+
Table 8: Credentials
Datatypes
Assignment of new values for new Message Types MUST be done through
IANA with "Expert Review" as defined in [RFC8126].
8.6. Challenge Types
+====+======================+
| ID | Data Type |
+====+======================+
| 0 | Not Specified |
+----+----------------------+
| 1 | EAP-CREDS-ASYMMETRIC |
+----+----------------------+
| 2 | EAP-CREDS-SYMMETRIC |
+----+----------------------+
Table 9: Challenge Type
Assignment of new values for new Message Types MUST be done through
IANA with "Expert Review" as defined in [RFC8126].
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8.7. Network Usage Datatypes
+========+==========================================+
| ID | Data Type |
+========+==========================================+
| 0 | Vendor-Specific |
+--------+------------------------------------------+
| 1 | Manufacturer Usage Description [RFC8520] |
+--------+------------------------------------------+
| 2 | Network Access Granting System |
+--------+------------------------------------------+
| 3 | Firmware Manifest |
+--------+------------------------------------------+
| 4..127 | Reserved for Future Use |
+--------+------------------------------------------+
Table 10: Network Usage Datatypes
Assignment of new values for new Message Types MUST be done through
IANA with "Expert Review" as defined in [RFC8126].
8.8. Credentials Encoding
+=========+============+
| ID | Encoding |
+=========+============+
| 0 | None (Raw) |
+---------+------------+
| 1 | DER |
+---------+------------+
| 2 | PEM |
+---------+------------+
| 3 | Base64 |
+---------+------------+
| 4 | JSON |
+---------+------------+
| 5 | XML |
+---------+------------+
| 6 | ASCII |
+---------+------------+
| 7 | UTF-8 |
+---------+------------+
| 200-254 | Reserved |
+---------+------------+
Table 11: Credentials
Encoding
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Assignment of new values for new Message Types MUST be done through
IANA with "Expert Review" as defined in [RFC8126].
8.9. Action Types
+=========+==============+================================+
| ID | Data Type | Description |
+=========+==============+================================+
| 0 | Registration | Registers New Credentials |
+---------+--------------+--------------------------------+
| 1 | Renewal | Renew an Existing Credential |
+---------+--------------+--------------------------------+
| 2 | Remove | Removes an Existing Credential |
+---------+--------------+--------------------------------+
| 200-254 | n/a | Reserved |
+---------+--------------+--------------------------------+
Table 12: Action Types
Assignment of new values for new Message Types MUST be done through
IANA with "Expert Review" as defined in [RFC8126].
8.10. Usage Metadata Types
+======+======================+
| Type | Description |
+======+======================+
| 0 | Binary (Unspecified) |
+------+----------------------+
| 1 | MUD File |
+------+----------------------+
| 2 | TEEP Manifest |
+------+----------------------+
Table 13: Usage Metadata Types
Assignment of new values for new Message Types MUST be done through
IANA with "Expert Review" as defined in [RFC8126].
9. Security Considerations
Several security considerations need to be explicitly considered for
the system administrators and application developers to understand
the weaknesses of the overall architecture.
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The most important security consideration when deploying EAP-CREDS is
related to the security of the outer channel. In particular, EAP-
CREDS assumes that the communication channel has been properly
authenticated and that the information exchanged between the Peer and
the Server are protected (i.e., confidentiality and integrity).
For example, if certificate-based authentication is used, the server
presents a certificate to the peer as part of the trust establishment
(or negotiation). The peer SHOULD verify the validity of the EAP
server certificate and SHOULD also examine the EAP server name
presented in the certificate in order to determine whether the EAP
server can be trusted. When performing server certificate
validation, implementations MUST provide support for the rules in
[RFC5280] for validating certificates against a known trust anchor.
10. Acknowledgments
The authors would like to thank everybody who provided insightful
comments and helped in the definition of the deployment
considerations.
11. Normative References
[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>.
[RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
Levkowetz, Ed., "Extensible Authentication Protocol
(EAP)", RFC 3748, DOI 10.17487/RFC3748, June 2004,
<https://www.rfc-editor.org/info/rfc3748>.
[RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen,
"Internet X.509 Public Key Infrastructure Certificate
Management Protocol (CMP)", RFC 4210,
DOI 10.17487/RFC4210, September 2005,
<https://www.rfc-editor.org/info/rfc4210>.
[RFC5272] Schaad, J. and M. Myers, "Certificate Management over CMS
(CMC)", RFC 5272, DOI 10.17487/RFC5272, June 2008,
<https://www.rfc-editor.org/info/rfc5272>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>.
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[RFC6402] Schaad, J., "Certificate Management over CMS (CMC)
Updates", RFC 6402, DOI 10.17487/RFC6402, November 2011,
<https://www.rfc-editor.org/info/rfc6402>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/info/rfc7030>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8520] Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
Description Specification", RFC 8520,
DOI 10.17487/RFC8520, March 2019,
<https://www.rfc-editor.org/info/rfc8520>.
Authors' Addresses
Massimiliano Pala
CableLabs
858 Coal Creek Cir
Louisville, CO 80027
US
Email: m.pala@openca.org
URI: http://www.linkedin.com/in/mpala
Yuan Tian
CableLabs
858 Coal Creek Cir
Louisville, CO 80027
US
Email: yuanalexiatian@gmail.com
URI: http://www.linkedin.com/in/ytian21
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