Double NAT VPN Privacy Protection via Dynamic IP Masking

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Solution Overview

Problem

Existing VPN protocols and implementations lack effective IP management functionality, leading to potential compromises in user privacy due to hard-coded client links to IP addresses and lack of dynamic IP address allocation.

Innovation Solution

The implementation of a double Network Address Translation (NAT) feature, where the traditional NAT sequence is modified to use a cryptographically enhanced sequence involving public keys and dynamic private IP addresses, effectively masking user network identification and avoiding the need for dynamic IP address assignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional NAT sequence is used, then IP address management is simplified, but user privacy is compromised due to hard-coded client links to IP addresses

Engineering Contradiction:

ImproveIP address management simplicityVSAvoiduser privacy compromise

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent segments the traditional single NAT process into a double NAT sequence. The first NAT translates the user's public IP to a dynamic private IP, and the second NAT translates the dynamic private IP to a static private IP. This segmentation breaks the direct link between the user's public IP and the VPN service, thereby protecting user privacy while maintaining IP management functionality

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an additional dimension to the NAT process by adding a cryptographic element (public key) to the translation sequence. Instead of directly mapping public IP to private IP, the system now uses public key cryptography to establish the mapping relationship, adding a layer of security and privacy protection without significantly complicating the overall process

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If dynamic IP address allocation is implemented, then user privacy is enhanced, but system complexity increases due to IP management overhead

Engineering Contradiction:

Improveuser privacy protectionVSAvoidIP management overhead

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements a self-service mechanism where the system automatically generates and manages dynamic private IP addresses without requiring manual intervention. The double NAT sequence automatically assigns dynamic private IPs to users based on their public keys, eliminating the need for complex manual IP management while enhancing user privacy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent performs preliminary actions by pre-configuring the double NAT sequence and cryptographic key pairs before users connect to the VPN service. This preparation work is done in advance, so that when users connect, the system can automatically establish secure connections with dynamic IP addresses without requiring complex real-time decision-making

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If cryptographic enhancement is added to NAT sequence, then user privacy is preserved, but processing overhead increases

Engineering Contradiction:

Improveuser privacy preservationVSAvoidprocessing overhead

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent applies cryptographic enhancement partially, only to the IP address mapping process, rather than encrypting all user data traffic. By using public key cryptography only for establishing the NAT mapping relationship, the system achieves privacy protection with minimal additional processing overhead, avoiding the excessive computational burden of full-data encryption

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20250184310A1Enhanced Privacy Preserving Access To A VPN Service

Publication Date: 2025.06.05 UAB 360 IT

AI summary

A VPN service assigns a first private IP address for a VPN concentrator and a second private IP address for a user device. Packets originating from the user device are modified by translating the second private IP address to a unique private IP address managed by the VPN concentrator, and translating the unique private IP address to a public IP address of the VPN concentrator. VPN session data, including the unique private IP address and an identifier associated with the user device, is registered in a peer hashtable. Inbound packets received from an external network are modified by translating the public IP address to the unique private IP address using the stored VPN session data, and then translating the unique private IP address to the second private IP address associated with the user device. The modified inbound packets are sent to the user device.