Internet DRAFT - draft-hb-emu-eap-over-ip
draft-hb-emu-eap-over-ip
Network Working Group H. Bidgoli, Ed.
Internet-Draft Nokia
Intended status: Standards Track N. Morris
Expires: 13 April 2024 Verizon
N. Cocker
Redhat
11 October 2023
EAP over IP
draft-hb-emu-eap-over-ip-00
Abstract
Extensible Authentication Protocol (EAP) is described in [RFC3748].
EAP typically runs directly over data link layers such as Point-to-
Point Protocol (PPP) or IEEE 802, without requiring IP.
IEEE802.1X-2004 clarifies some aspect of the EAP over Layer 2 PDUs.
IEEE802.1X-2010 introduces MACsec Key Agreement Protocol (MKA) which
uses EAPOL. In IEEE 802.1X-2010 the existing EAPOL (EAP over LANs)
PDU formats have not been modified, but additional EAPOL PDUs have
been added to support MKA. MKA is used for discovering peers and
their mutual authentication, to agree the secrete keys (SAKs) used by
MACsec for symmetric shared key cryptography. This document
describes procedures to transport EAP and ultimately MKA PDUs over a
IP network to distribute SAKs for symmetric key cryptography.
Status of This Memo
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Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
3. EAP over IP . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Use of UDP to identify MKA . . . . . . . . . . . . . . . 4
3.2. IP header . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3. Security Channel Identifier . . . . . . . . . . . . . . . 4
3.4. Packet format . . . . . . . . . . . . . . . . . . . . . . 5
4. IANA Consideration . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5
7. Informative References . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
Currently, most encryption protocols use Public Key Infrastructure
(PKI) to distribute symmetric shared keys. Current PKIs algorithms
and key lengths are vulnerable to post quantum computers attacks such
as "steal/harvest now, decrypt later" and most highly secure
organizations are looking for options of quantum safe key
distribution.
IIEEE802.1X-2010 introduces MKA, a secure fully distributed point-to-
point or multipoint-to-multipoint transport. MKA consists of a
number of applications for that transport, including the distribution
of SAKs by an elected key server using AES Key Wrap.. It is widely
accepted that AES ciphers with key length of 256 are safe Post-
quantum Cryptography (PQC). IEEE802.1X-2010 farther explains in
section 9.3.3 that the keys derived for AES cipher is from a secure
Connectivity Association Key (CAK) and a Key Derivation Function
(KDF), the CAK can be drived from multiple methods including Pre-
shared keys (PSKs), as an example these PSKs can be manually
configured via a secure management connection and consist of a 64 Hex
string for CMAC-AES-256 key wrap.
With those attributes in mind, MKA can be a PQC protocol to
distribute symmetric shared keys within a network.
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As such, it would be ideal to extend EAP and MKA into IP networks to
allow MKA to distribute symmetric shared keys within an IP domain.
This document describes a simple method to identify EAP packet with
in a IP network and process them according, including MKA PDUs.
2. Conventions used in this document
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].
3. EAP over IP
802.1x-2010 section 9 explains the MKA (MACSec Key Agreement
Protocol) in detail. The first and most important note is in the
last paragraph of section 9.4 which points out that MKA is designed
for mutual authentication of participants in a connectivity
association (CA), and can be used for any application.
Section 9 of IEEE802.1x-2010 also points out that MKA:
1. allows PEERs to discover each other and authenticate each other
via the CAK, and agree on a symmetric secret keys (SAKs) used by the
application.
2. MKA protects and distributes SAKs via AES Key wrap, and more
importantly a PQC AES-256 key wrap
3. The SAK is created by the Key Server and distributed to the PEERs
with in the connectivity association, section 9 of the
IEEE802.1x-2010 describes the key server selection.
4. MKA manages the SAK installation which is used by the
applications that secure the data transmitted and received.
5. The root of key hierarchy for any given instance of MKA is the
secure CAK. Each CAK is identified by the CA key NAME (CKN) that
allows each of the MKA participants to select which CAK to use to
process a received MKA PDUs.
These attributes are ideal to use MKA to authenticate peers and
distribute symmetric keys in a PQC fashion even in an IP or MPLS
network. As an example MKA over IP can be used for signaling
symmetric keys for proprietary MPLS encryption or such.
To distribute MKA over an IP network there is two concerns to be
solved:
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1. How to identify the MKA PDUs with in an IP domain
2. How to transport MKA PDUs from one PEER to another
3.1. Use of UDP to identify MKA
To solve the first problem of identifying EAP or MKA PDUs within an
IP domain, the destination PEER needs to identify this packet as an
MKA packet and extract it, to be processed as described in
IEEE802.1X-2010. To identify the PDU as a MKA PDU within IP domain,
UDP can be used. More precisely, a specific UDP port assigned to
MKA, to identify MKA PDUs uniquely in the network. This UDP port can
be a random UDP port chosen by the provider, or it can be a well
known UDP port assigned by IANA, either case it has to be same
network wide. UDP is ideal for this MKA identification, as it is
best effort protocol and does not have a retransmission mechanism as
TCP does, in case of lost packets. MKA fits well with this use-case
because it has a heartbeat built in, where loss of MKA packets would
bring the MKA session down.
3.2. IP header
Any IP address family (AF) can be used to transport the MKA over UDP
through the IP domain. The source IP can be the loopback IP address
used by the source of the application and the destination IP can be
the loopback IP used by the application on its PEER. Of course the
IP protocol will be set to UDP. With this method when the packet
arrives on the PEER router, the UDP port can be examined and the
packet processed accordingly. In this case the UDP packet will
identify the PDU as a MKA PDU and will extract it to the MKA
application to authenticate the PEER and extract the SAK by
decrypting the key wrap via the CAK that is identified by the CKN and
CMAC AES-256. From this point on the SAK can be used by the
application to encrypt the datapath. As an example, if the symmetric
key size is 256 it can be used with the AES algorithm to create a PQC
secure datapath for the application.
3.3. Security Channel Identifier
MACsec uses the PORT ID as its security channel Identifier (SCI).
The SCI, for IP or MPLS applications can be modified based on the
application requirements and how the application flow can be uniquely
identified within the network. As an example for MPLS the SCI can be
a unique encryption SID that identifies the encrypting node within
the network and the MPLS flowID or tunnelID within that encrypting
node. The assignment of SCI for different IP/MPLS applications is
beyond the scope of this document.
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3.4. Packet format
The packet format reuses the entire 802.1x packet format as described
in the IEEE802.1X-2010 (i.e. it reuses the packet format that follows
the Ethernet header with ethertype (0x888e) minus the Ethernet
header.). Doing so will allow the routers that have implementations
of MACsec and MKA, to leverage the current EAPoL and MKA
implementations, and extend these implemention to be used to process
the EAP over IP packet. An example of this without reinventing the
wheel would be to remove the IP and UDP headers and send the
802.1x-2010 packet (with type MKA) to the MKA application to process
the MKA PDU.
As such the final packet format is Ethernet header with ethertype of
(IP) followed by IP header with protocol (UDP) where the UDP port is
a well known MKA UDP port or a a UDP port that is assigned within the
network to identify the MKA PDU.
4. IANA Consideration
Assign a UDP port for EAP over IP identification.
5. Security Considerations
NA
6. Acknowledgments
7. Informative References
[RFC2119] "S. Bradner "Key words for use in RFCs to Indicate
Requirements Levels"".
[RFC3748] "B. Aboda, L. Blunk, J. Vollbrecht, J.Carlson "Extensible
Authentication Protocol"", June 2004.
Authors' Addresses
Hooman Bidgoli (editor)
Nokia
Ottawa
Canada
Email: hooman.bidgoli@nokia.com
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Nicklous Morris
Verizon
United States of America
Email: nicklous.morris@verizonwireless.com
Nabeel Cocker
Redhat
New York,
United States of America
Email: ncocker@redhat.com
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