Internet DRAFT - draft-yu-keydistribution
draft-yu-keydistribution
Network Working Group Y. Yang
Internet-Draft P. Guo
Intended status: Informational China Automotive Innovation Corporation
Expires: 18 April 2024 J. Yu
A. Hu
Purple Mountain Laboratories, China
October 2023
Model and Test Methods for LTE-V2X Physical Layer Key Distribution
System
draft-yu-keydistribution-01
Abstract
There are several key distribution systems based on the physical
layer of the LTE Vehicle-to-Everything (V2X) communication system,
utilizing the random and high-agreement secret key generation schemes
from noisy wideband channels. These systems are used in conjunction
with physical layer authentication systems that are also based on
physical characteristics. To characterize these systems, this
document proposes a reference model and several test methods of main
technical parameters of such systems, including average key
generation rate as well as the consistency and the randomness of
generated key bits.
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Terms and Definitions . . . . . . . . . . . . . . . . . . . . 3
3.1. LTE-V2X physical layer key distribution system . . . . . 3
3.2. Sender . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.3. Receiver . . . . . . . . . . . . . . . . . . . . . . . . 3
3.4. Negotiation signal . . . . . . . . . . . . . . . . . . . 3
4. Network Topology of LTE-V2X Physical Layer Key Distribution
System . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Test Methods of LTE-V2X Physical Layer Key Distribution
System . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. The Average Key Generation Rate of LTE-V2X Physical Layer
Key Distribution System . . . . . . . . . . . . . . . . . 6
5.1.1. Test Content . . . . . . . . . . . . . . . . . . . . 6
5.1.2. Test Configuration . . . . . . . . . . . . . . . . . 6
5.1.3. Test Steps . . . . . . . . . . . . . . . . . . . . . 7
5.2. Output Key Consistency of LTE-V2X Physical Layer Key
Distribution System . . . . . . . . . . . . . . . . . . . 7
5.2.1. Test Content . . . . . . . . . . . . . . . . . . . . 7
5.2.2. Test Configuration . . . . . . . . . . . . . . . . . 7
5.2.3. Test Steps . . . . . . . . . . . . . . . . . . . . . 7
5.2.4. Notes . . . . . . . . . . . . . . . . . . . . . . . . 8
5.3. Output Key Randomness of LTE-V2X Physical Layer Key
Distribution System . . . . . . . . . . . . . . . . . . . 8
5.3.1. Test Content . . . . . . . . . . . . . . . . . . . . 8
5.3.2. Test Configuration . . . . . . . . . . . . . . . . . 8
5.3.3. Test Steps . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Normative References . . . . . . . . . . . . . . . . . . . . 9
Appendix A. Workflow of LTE-V2X Physical Layer Key Distribution
System Based on Message Reconciliation . . . . . . . . . 9
Appendix B. Workflow of LTE-V2X Physical Layer Key Distribution
System Based on Error correcting Codes . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
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1. Introduction
There are several key distribution systems based on the physical
layer of the LTE Vehicle-to-Everything (V2X) communication system,
utilizing the random and high-agreement secret key generation schemes
from noisy wideband channels. These systems are used in conjunction
with physical layer authentication systems that are also based on
physical characteristics. To characterize these systems, this
document proposes a reference model and several test methods of main
technical parameters of such systems, including average key
generation rate as well as the consistency and the randomness of
generated key bits.
2. Conventions and Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Terms and Definitions
3.1. LTE-V2X physical layer key distribution system
Based on LTE-V2X physical layer channel characteristics, a LTE-V2X
physical layer key distribution system is used to generatekey streams
with high consistency for two communicating parties using LTE-V2X.
3.2. Sender
The sender initiates the key distribution protocol in LTE-V2X
physical layer key distribution system. It has duplex communication
capability to send and receive signals.
3.3. Receiver
The receiver responds to the key distribution protocol in LTE-V2X
physical layer key distribution system. It has duplex communication
capability to send and receive signals.
3.4. Negotiation signal
Negotiation signal is used to transmit additional information for the
key distribution protocol in LTE-V2X physical layer key distribution
system. It may be sent and received by using a separate physical
layer transceiver mechanism or multiplexing LTE-V2X physical layer
signal transceiver mechanisms.
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4. Network Topology of LTE-V2X Physical Layer Key Distribution System
The reference model of the LTE-V2X physical layer key distribution
system is shown in Fig. 1, including devices such as the sender and
the receiver.
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+-----------------------------------------------+
| |
| +-----------+ +-------+ +-----------+ |
| |LTE-V2X PHY| |LTE-V2X| |LTE-V2X PHY| | Sn
| | Modem +---+ Upper +---+ Management+--+----
| | Module | |Control| | Program | |
| +-----+-----+ +-------+ +-----+-----+ |
| | | |
| +-------+-------+ +-----+-----+ |
| | LTE-V2X PHY | |Channel Key| | Sk
| |Synchronisation+-------------+ Extraction+--+----
| | Module | | Module | |
| +-------+-------+ +-----+-----+ |
| | | |
| +-----+-----+ +-----+-----+ |
| |LTE-V2X PHY| |Negotiation| | Sd
| |Transceiver| | Signal +--+----
| | Module | | Interface | |
| +-----+-----+ +-----+-----+ |
| | Sender | |
+----------+---------------------------+--------+
|Sq |
| |
| |
| |
|Rq |
+----------+---------------------------+--------+
| | Receiver | |
| +-----+-----+ +-----+-----+ |
| |LTE-V2X PHY| |Negotiation| | Rd
| |Transceiver| | Signal +--+----
| | Module | | Interface | |
| +-----+-----+ +-----+-----+ |
| | | |
| +-------+-------+ +-----+-----+ |
| | LTE-V2X PHY | |Channel Key| | Rk
| |Synchronisation+-------------+ Extraction+--+----
| | Module | | Module | |
| +-------+-------+ +-----+-----+ |
| | | |
| +-----+-----+ +-------+ +-----+-----+ |
| |LTE-V2X PHY| |LTE-V2X| |LTE-V2X PHY| | Rn
| | Modem +---+ Upper +---+ Management+--+----
| | Module | |Control| | Program | |
| +-----------+ +-------+ +-----------+ |
| |
+-----------------------------------------------+
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Figure 1: The model and reference points of the LTE-V2X physical
layer key distribution system
Eight reference points of LTE-V2X physical layer key distribution
system are defined in Fig. 1 with the following meanings:
* Sq represents the transceiver interface of the sender;
* Rq represents the transceiver interface of the receiver;
* Sd represents the negotiation signal interface point of the
sender;
* Rd represents the negotiation signal interface point of the
receiver;
* Sk represents the key interface reference point of the sender;
* Rk represents the key interface reference point of the receiver;
* Sn represents the management program interface reference point of
the sender;
* Rn represents the management program interface reference point of
the receiver.
5. Test Methods of LTE-V2X Physical Layer Key Distribution System
5.1. The Average Key Generation Rate of LTE-V2X Physical Layer Key
Distribution System
5.1.1. Test Content
Test the average key generation rate of LTE-V2X physical layer key
distribution system in the specified scenario. The average key
generation rate is defined as the number of bits/generation time of
the key generated by the LTE-V2X physical layer key distribution
system at the sender or receiver side over a period of time.
5.1.2. Test Configuration
The test configuration is shown in Fig. 2, and the test software is
LTE-V2X physical layer key distribution system management program.
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+--------------+
+------------+Upper computer+------------+
| +--------------+ |
|Sk |Rk
+------------+------------+ +------------+------------+
| The sender of the key |Sd Rd| The receiver of the key |
| +--------------+ |
| distribution system |Sq Rq| distribution system |
+-------------------------+ +-------------------------+
Figure 2: The test configuration of the average key generation rate
5.1.3. Test Steps
Perform the test as follows:
1.Record the generated keys by the upper computer and count for 10
min, then calculate the average key generation rate;
2.Calculate the average key generation rate by the upper computer to
record the generated keys and counting for 10 min;
3.Repeat the test three times and take the average value to obtain
the average key generation rate of the system in the specified
scenario.
5.2. Output Key Consistency of LTE-V2X Physical Layer Key Distribution
System
5.2.1. Test Content
The key files generated by the sender and receiver of LTE-V2X
physical layer key distribution system are compared for content
consistency.
5.2.2. Test Configuration
The test configuration is shown in Fig. 2, and the test software is
file comparison software.
5.2.3. Test Steps
Perform the test as follows:
1.Carry out the test configuration as in Fig. 2, and export the
output key files of the sender and receiver at the same time by the
upper computer, and the key file is not less than 125KB.
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2.Use the file comparison software to compare the binary file
contents of the output key files generated at both ends and record
the comparison results.
5.2.4. Notes
If the output key file is an encapsulated message or encrypted, the
system shall support key message parsing or decryption.
5.3. Output Key Randomness of LTE-V2X Physical Layer Key Distribution
System
5.3.1. Test Content
The key file generated by LTE-V2X physical layer key distribution
system is tested for randomness in accordance with the requirements
of AIS-20/31.
5.3.2. Test Configuration
The test configuration is shown in Fig. 2, and the test software is
randomness test software.
5.3.3. Test Steps
Perform the test as follows:
1.Carry out the test configuration as in Fig. 2, and export the
output key file of the sender and receiver at the same time by the
upper computer, and the key file is not less than 125KB.
2.Using the randomness test software that complies with the test
cases and evaluation methods required by AIS-20/31, analyze the
randomness of the output key files generated at both ends in terms of
binary random numbers and record the test results.
6. Security Considerations
This section will address only security considerations associated
with the test environment of LTE-V2X Physical Layer Key Distribution
Systems. It is necessary to ensure that the upper computer as well
as the sender and the receiver are in a secure and trusted
environment.
7. IANA Considerations
This document has no IANA actions.
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8. 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/rfc/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
Appendix A. Workflow of LTE-V2X Physical Layer Key Distribution System
Based on Message Reconciliation
The flow of Message Reconciliation-based LTE-V2X Physical Layer Key
Distribution System usually includes several blocks such as channel
detection, signal synchronisation, channel estimation, feature
quantization, information reconciliation and privacy amplification,
as shown in Fig. 3.
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Sender Receiver
+---------+ +-------+ +---------+
| Channel +---------+LTE-V2X+------->| Channel |
|Detection| |Signal | |Detection|
+----+----+ +-------+ +----+----+
| |
v v
+---------------+ +---------------+
| Signal | | Signal |
|Synchronisation| |Synchronisation|
+-------+-------+ +-------+-------+
| |
v v
+----------+ +----------+
| Channel | | Channel |
|Estimation| |Estimation|
+----+-----+ +----+-----+
| |
v v
+------------+ +------------+
| Feature | | Feature |
|Quantisation| |Quantisation|
+-----+------+ +-------+ +-----+------+
| |Initial| |
+--------------+ Key +-------------+
| +-------+ |
v v
+--------------+ +-----------+ +--------------+
| Information | |Negotiation| | Information |
|Reconciliation|<----+ Signal +--->|Reconciliation|
+-------+------+ +-----------+ +------+-------+
| |
| +-----------+ |
+------------+Negotiation+-----------+
| | Key | |
v +-----------+ v
+-------------+ +-------------+
| Privacy | | Privacy |
|Amplification| |Amplification|
+------+------+ +------+------+
| +---------+ |
+-------------+Final Key+------------+
v +---------+ v
Figure 3: Workflow of LTE-V2X physical layer key distribution
system based on message reconciliation
The specific steps of the workflow are as follows:
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1.Channel Detection: The sender sends an LTE-V2X physical layer
signal to the receiver, and the receiver shall be able to detect and
receive this signal.
2.Signal Synchronization: The known frequency-conducting signal
sequence in the received signal is extracted by coarse and fine
synchronization. Frequency bias estimation and frequency
compensation are generally required since the received signal will
have frequency bias deviation due to the channel.
3.Channel Estimation: Extract channel characteristics for the
frequency compensated received signal.
4.Feature Quantization: Discrete continuous channel state information
into streams of 0 and 1 bits to obtain the initial key.
5.Message Reconciliation: Due to channel and estimation algorithms,
there will be inconsistent bits in the initial keys of the two
communicating parties. Obtaining the symmetric shared key by
removing the inconsistent bits in the interactions of negotiation
signals, or using the error correcting capability of channel coding
techniques can help achieve encrypted transmission of the message.
6.Privacy Amplification: Using the one-way mapping property of the
hash function to improve the randomness and security of the shared
key.
Appendix B. Workflow of LTE-V2X Physical Layer Key Distribution System
Based on Error correcting Codes
LTE-V2X physical layer key distribution system based on error
correcting codes does not seek to achieve identical key generation
results at the sender and receiver, but instead it uses error
correcting codes and one-time encryption and decryption in
conjunction. Error correcting code decoding recovers a small number
of error bits, and one-time encryption and decryption would not
introduce additional error bits other than the key generation error.
The process usually includes several parts such as channel detection,
signal synchronization, channel estimation, feature quantization,
error correcting coding, synchronous encryption, synchronous
decryption, and error correcting decoding, as shown in Fig. 4.
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Sender Receiver
+---------+ +-------+ +---------+
| Channel | |LTE-V2X| | Channel |
| +-----+ +---->| |
|Detection| |Signal | |Detection|
+----+----+ +-------+ +----+----+
| |
v v
+---------------+ +---------------+
| Signal | | Signal |
|Synchronisation| |Synchronisation|
+-------+-------+ +-------+-------+
| |
v v
+-----------+ +-----------+
| Channel | | Channel |
|Estimation | |Estimation |
+-----+-----+ +-----+-----+
| |
v v
+-------------+ +-------------+
| Feature | | Feature |
|Quantisation | |Quantisation |
+------+------+ +------+------+
| |
v v
+-----------+ +-------+ +-----------+
|Synchronous| |LTE-V2X| |Synchronous|
| +--->| +--->| |
|Encryption | |Signal | |Decryption |
+-----------+ +-------+ +-----------+
^ ^
| |
+----+-----+ +----+-----+
Send | Error | | Error | Receive
-------->|Correcting| |Correcting+-------->
Message | Coding | | Decoding | Message
+----------+ +----------+
Figure 4: Workflow of LTE-V2X physical layer key distribution
system based on error correcting codes
The specific steps of the workflow are as follows:
1.Channel Detection: The sender sends an LTE-V2X physical layer
signal to the receiver, and the receiver shall be able to detect and
receive this signal.
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2.Signal Synchronization: The known frequency-conducting signal
sequence in the received signal is extracted by coarse and fine
synchronization. Frequency bias estimation and frequency
compensation are generally required since the received signal will
have frequency bias deviation due to the channel.
3.Channel Estimation: Extract channel characteristics for the
frequency compensated received signal.
4.Feature Quantization: Discrete continuous channel state information
into streams of 0 and 1 bits to obtain the one-time key.
5.Error Correcting Coding: Error correcting coding of the plaintext
bitstream of the sending message.
6.Synchronous Encryption: The ciphertext bit stream is obtained by
bit wise dissimilarity between the one-time secret key generated by
the sender and the bit stream after error correction coding. Add
appropriate synchronization information of one-time secret key,
modulate and transmit it using the LTE-V2X channel.
7.Synchronous Decryption: Receive the signal from LTE-V2X channel and
demodulate it, recover synchronization information of one-time secret
key, delete synchronization information of key to get the ciphertext
message bit stream, and then bitwise dissimilar the corresponding
one-time key of the receiver and the ciphertext bit stream to obtain
the plaintext bit stream with error correction code.
8.Error Correcting Decoding: The plaintext bit stream containing the
error correcting code is error correcting decoded to get the received
information.
Authors' Addresses
Yanzhao Yang
China Automotive Innovation Corporation
Email: yangyanzhao@t3caic.com
Peng Guo
China Automotive Innovation Corporation
Email: guopeng@t3caic.com
Jiabao Yu
Purple Mountain Laboratories, China
Email: yujiabao@pmlabs.com.cn
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Aiqun Hu
Purple Mountain Laboratories, China
Email: aqhu@seu.edu.cn
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