Layer-3 Small Data Encryption Using Keystream Indication

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Solution Overview

Problem

Current encryption mechanisms in M2M communications systems do not provide confidentiality protection for initial layer-3 messages, particularly for small data transmissions in SMS messages, which are essential for secure machine-to-machine communication.

Innovation Solution

An encryption method using a keystream generated by an evolved packet system encryption algorithm (EEA) performs an exclusive OR operation on the initial layer-3 message to encrypt small data, with an added encryption indication to ensure the network side can decrypt the data, ensuring confidentiality protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current encryption mechanisms are used in M2M communications systems, then existing data transmission is protected, but initial layer-3 messages and small data in SMS messages lack confidentiality protection

Engineering Contradiction:
Improveconfidentiality protectionVSAvoidapplicability to initial layer-3 messages
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the data into different parts: the initial layer-3 message header remains unencrypted for protocol compatibility, while only the specific small data payload is encrypted using the EEA algorithm. This selective encryption approach provides confidentiality protection where needed while maintaining the functional requirements of the initial message structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces new parameters including an encryption indication field in the message header and modifies the data transmission format to include encrypted portions. These parameter changes enable the system to distinguish between encrypted and unencrypted data segments, allowing initial layer-3 messages to be handled with confidentiality protection while maintaining compatibility with existing protocols.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If encryption is applied to initial layer-3 messages, then confidentiality protection is provided, but the message structure and processing complexity increase

Engineering Contradiction:
Improveconfidentiality protectionVSAvoidencryption processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The encryption indication is prepared and set in the message header before the actual encryption process. The system pre-configures the encryption parameters and identifies which portions of the message need encryption, allowing the main processor to handle the message structure while dedicated encryption modules process only the necessary data segments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts only the specific small data portions from the initial layer-3 message that require confidentiality protection, leaving the message header and other non-sensitive portions unencrypted. This extraction approach minimizes the amount of data requiring encryption processing while still providing protection for the critical information.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If small data in SMS messages is encrypted, then confidentiality is ensured, but decryption capability on the network side must be maintained

Engineering Contradiction:
Improveconfidentiality protectionVSAvoiddecryption operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The encryption indication field provides feedback to the receiving end about which portions of the message are encrypted. This feedback mechanism allows the network side to automatically identify and apply the appropriate decryption processes without manual intervention, maintaining ease of operation while ensuring confidentiality protection is properly applied and reversed.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2765734B1Encryption method, decryption method, and related device
Publication Date: 2025.12.10 HUAWEI TECH CO LTD
  • EP2765734B1 patent drawingFigure 1~2
  • EP2765734B1 patent drawingFigure 3~4a
  • EP2765734B1 patent drawingFigure 4b~4c

AI summary

Embodiments of the present invention provide an encryption method, a decryption method, and a related apparatus. According to the present invention, secure transmission of small data can be ensured. The encryption method includes: generating a keystream, where the keystream is used to encrypt a part of data to be encrypted in an initial layer-3 message, and the part of data to be encrypted includes small data; generating, by performing an exclusive OR operation on the keystream and the initial layer-3 message, an initial layer-3 message in which the part of data is encrypted; and sending the initial layer-3 message in which the part of data is encrypted, where the initial layer-3 message includes an added encryption indication, and the encryption indication is used to indicate that the part of data to be encrypted in the initial layer-3 message is encrypted, so that a network side generates a keystream according to the added encryption indication, and then decrypts, according to the generated keystream, the initial layer-3 message in which the part of data is encrypted.