SIP Registration Security via Public Key Encryption

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Solution Overview

Problem

Current methods for securely registering User Equipment (UE) with an IP Multimedia Subsystem (IMS) network, such as those using IPSec and TLS, expose user information during initial SIP registration and consume network resources, leading to potential eavesdropping and increased registration times.

Innovation Solution

The method involves encrypting SIP REGISTER messages with the public key part of a public-private key pair belonging to the IMS network or its controller, allowing secure decryption and response encryption using the corresponding private key, thereby protecting registration information and reducing network bandwidth usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If IPSec and TLS protocols are used to secure SIP registration, then security is improved, but network resource consumption increases and registration time increases

Engineering Contradiction:
ImprovesecurityVSAvoidnetwork resource consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the essential security function from the complex IPSec and TLS protocols, implementing only the necessary public key encryption for SIP registration. This selective approach removes unnecessary protocol overhead while retaining core security capabilities, thereby reducing network resource consumption without compromising essential security requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of establishing a full secure tunnel first (as in traditional IPSec/TLS approaches), the patent inverts the approach by applying encryption selectively to only the registration messages. This reversal avoids the overhead of establishing complete secure channels while still protecting the critical registration data.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If IPSec and TLS protocols are used to secure SIP registration, then security is improved, but registration time increases

Engineering Contradiction:
ImprovesecurityVSAvoidregistration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts only the essential encryption functionality needed for security, eliminating the time-consuming handshake and negotiation phases of full TLS/IPSec protocols. By applying encryption directly to registration messages without establishing complete secure channels first, the essential security function is achieved with minimal time overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent skips the lengthy TLS handshake and IPSec negotiation phases by directly applying public key encryption to the registration messages. This allows the system to rush through the critical security protection step without performing unnecessary intermediate protocol steps, thereby significantly reducing registration time while maintaining security.

Inventive Principle:
Principle #21Skipping (Rushing through)

3Loss of energy

If SIP registration messages are sent in plaintext, then network bandwidth usage is reduced, but user information security is compromised

Engineering Contradiction:
Improvenetwork bandwidth usageVSAvoideavesdropping risk
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by encrypting only the specific registration messages that contain sensitive user information, rather than encrypting all SIP traffic. This selective encryption approach protects vulnerable data points while maintaining efficient plaintext transmission for other non-sensitive communications, thereby balancing security needs with bandwidth efficiency.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3682609B1Signal plane protection within a communications network
Publication Date: 2022.03.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3682609B1 patent drawingFigure 1
  • EP3682609B1 patent drawingFigure 2
  • EP3682609B1 patent drawingFigure 3

AI summary

A method of securely registering a User Equipment, UE, with an IP Multimedia Subsystem, IMS, network. The method comprises sending from the UE to the IMS network, a Session Initiation Protocol, SIP, REGISTER message comprising information encrypted using the public key part of a public-private key pair belonging to the IMS network or to a controller of the IMS network.