CoAP Authentication via Segmented Nonce and Token Validation

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Solution Overview

Problem

The Constrained Application Protocol (CoAP) lacks authentication mechanisms for message senders, which compromises the security of communication, particularly in scenarios where Datagram Transport Layer Security (DTLS) does not provide adequate authentication.

Innovation Solution

Incorporating authentication data within CoAP messages, including a nonce and security tokens, to enable message validation and prevent replay attacks, ensuring the authenticity of the sender and integrity of the message.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If DTLS is used to secure CoAP communications, then communication security is improved, but sender authentication capability remains insufficient

Engineering Contradiction:
Improvecommunication securityVSAvoidlack of sender authentication
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The authentication mechanism is segmented into distinct components: a nonce generated by the recipient, security tokens embedded in CoAP messages, and separate validation logic. This segmentation allows DTLS to handle transport-layer security while the added components specifically address sender authentication, resolving the contradiction by dividing security functions into specialized segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The recipient generates a nonce and includes it in the CoAP message before transmission. This preliminary action creates an authentication challenge that the sender must respond to with a valid security token, establishing sender authentication capability in advance of the actual communication exchange, thereby resolving the authentication deficiency in DTLS.

Inventive Principle:
Principle #10Preliminary action

2Object-generated harmful factors

If authentication data is added to CoAP messages, then sender authentication is improved, but message size increases

Engineering Contradiction:
Improvesender authentication capabilityVSAvoidmessage size
Core Design Contradiction:
Object-generated harmful factorsVSQuantity of substance

Solution Approach 1:

Authentication data (nonce and security tokens) is added locally and selectively to specific CoAP messages that require authentication, rather than universally to all messages. This local quality approach ensures that only messages needing enhanced authentication carry the additional data burden, minimizing overall message size increases while maintaining authentication capability where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The authentication mechanism uses compact parameter representations: fixed-length nonces and efficiently encoded security tokens that fit within existing CoAP message structures. By optimizing the parameter sizes and using efficient encoding schemes, the message size increase is minimized while still providing robust sender authentication.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If security tokens and nonces are implemented, then replay attack detection is improved, but processing complexity increases

Engineering Contradiction:
Improvereplay attack vulnerabilityVSAvoidmessage validation complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The validation logic is designed to be self-service and automated: the recipient validates the nonce and security token using predetermined algorithms and shared secrets without requiring complex manual verification processes. This self-service approach handles the increased processing complexity through automation, maintaining replay attack detection capability while minimizing the burden of validation complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The authentication mechanism incorporates feedback loops where the validity of security tokens is immediately verified against previously exchanged nonces and shared credentials. This feedback mechanism provides real-time replay attack detection through systematic validation, managing processing complexity through structured feedback rather than ad-hoc verification.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2991309B1Increased communication security
Publication Date: 2024.01.17 IDAAX TECH PTE LTD
  • EP2991309B1 patent drawingFigure 1
  • EP2991309B1 patent drawingFigure 2
  • EP2991309B1 patent drawingFigure 3

AI summary

A method of increasing communication security may include receiving, at a first computer system, a first message including a first data portion and a second data portion, wherein the first data portion is associated with a security token, wherein the first data portion includes a first instance of a session key, and wherein the second data portion includes a second instance of the session key. The method may also include generating a second message including the first data portion. The method may further include communicating the second message from the first computer system to a second computer system.