Network Working Group S. M. K. Varigonda
Internet-Draft Samsung R&D Bangalore
Intended status: Experimental R. S. R. Sige
Expires: 14 November 2025 Spirent
13 May 2025
Precision Time Protocol (PTP) Authentication Extension
draft-kumarvarigonda-ptp-auth-extension-00
Abstract
Precision Time Protocol (PTP), as defined in IEEE 1588-2019, lacks
cryptographic security mechanisms, exposing deployments to message
spoofing, delay attacks, and timestamp manipulation. This document
defines an optional Authentication TLV (AUTH_TLV) using modern
Authenticated Encryption with Associated Data (AEAD) algorithms to
ensure message integrity,authenticity, and replay protection. It
also provides example configurations, implementation approaches, and
test strategies.
Status of This Memo
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This Internet-Draft will expire on 14 November 2025.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 2
3. AUTH TLV Format . . . . . . . . . . . . . . . . . . . . . . . 2
4. AEAD Algorithm Support . . . . . . . . . . . . . . . . . . . 3
5. Key Management . . . . . . . . . . . . . . . . . . . . . . . 3
6. Backward Compatibility . . . . . . . . . . . . . . . . . . . 3
7. Example Implementations . . . . . . . . . . . . . . . . . . . 3
7.1. Software (ptp4l) . . . . . . . . . . . . . . . . . . . . 3
7.2. Hardware . . . . . . . . . . . . . . . . . . . . . . . . 4
7.3. Wireshark Filters . . . . . . . . . . . . . . . . . . . . 4
8. Security Considerations . . . . . . . . . . . . . . . . . . . 4
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
10. Appendix A. Sample ptp4l.conf . . . . . . . . . . . . . . . 4
11. Appendix B. Example AUTH TLV . . . . . . . . . . . . . . . . 5
12. Appendix C: Change Log . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
The PTP protocol is widely used for time synchronization in telecom,
industrial automation, and financial systems. However, the protocol
lacks built-in security. This draft proposes a lightweight extension
for cryptographic message authentication and integrity without
impacting compatibility.
2. Problem Statement
PTP messages are susceptible to:
* Spoofing of SYNC or ANNOUNCE messages
* Timestamp alteration during transit
* Replay or delay injection attacks
These vulnerabilities can compromise distributed systems relying on
synchronized time for control, logs, or access control.
3. AUTH TLV Format
A new TLV is introduced as follows:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xFE00 (TEMP) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AEAD Algorithm ID | Tag Length (bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce (96 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Authentication Tag (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The nonce is derived from the message sequence ID and clock ID.
Supported AEAD algorithms:
* AES-GCM-128/256 (ID 0x0001)
* ChaCha20-Poly1305 (ID 0x0002)
4. AEAD Algorithm Support
The AUTH TLV uses AEAD for combined encryption and authentication,
though only authentication is used in this extension. The message
body is used as AAD, and only the tag is appended in the TLV.
5. Key Management
Keys may be provisioned using:
* Manual configuration (secure local access)
* Enrollment via PKI (e.g., EST, SCEP)
* TPM-based secure provisioning (future work)
6. Backward Compatibility
As per IEEE 1588 TLV rules, unknown TLVs are ignored by legacy
systems. Authentication failures are not enforced unless explicitly
configured.
7. Example Implementations
7.1. Software (ptp4l)
Modify ptp4l to:
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* Enable auth_tlv_enable = 1 in configuration
* Parse and verify AUTH TLV using OpenSSL or libsodium
* Generate tag for outgoing messages with unique nonce
7.2. Hardware
Suggested flow for hardware timestamping with AUTH:
* Timestamp before encryption
* Use on-NIC AEAD (if supported) or offload via driver extensions
* Expose configuration via ethtool or netlink extensions
7.3. Wireshark Filters
Use the following filter:
ptp.messageType && frame contains 0xfe00
Custom dissector patches can be developed to interpret the AUTH_TLV
fields.
8. Security Considerations
- Nonce reuse must be avoided; use a deterministic counter with a
unique base per node. - Replay attacks are mitigated by validating
sequence IDs and time windows. - Integrity is ensured only for
messages using AUTH TLV.
9. IANA Considerations
Request registration of:
* AUTH_TLV type code (tentatively 0xFE00 for testing)
* AEAD Algorithm ID registry for PTP
10. Appendix A. Sample ptp4l.conf
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[global]
auth_tlv_enable 1
auth_algorithm 2
auth_key 00112233445566778899aabbccddeeff00112233445566778899aabbccddeeff
auth_nonce_base 112233445566778899aabb
auth_tag_len 16
auth_debug 1
11. Appendix B. Example AUTH TLV
TLV Type: 0xFE00
Length: 32
AEAD ID: 0x0002
Tag Len: 16
Nonce: 00 11 22 33 44 55 66 77 88 99 aa bb
Tag: c0 ff ee 12 34 56 78 90 de ad be ef 12 34 56 78
12. Appendix C: Change Log
draft-kumarvarigonda-ospf-precomputed-frr-00
- Initial version including use case, diagram, and examples.
Authors' Addresses
Srinivasa Mohan Kumar Varigonda
Samsung R&D Bangalore
Email: sri.mohan@samsung.com
Rama Subba Reddy Sige
Spirent
Email: rama.subbareddy@spirent.com
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