Group License Encryption Reducing Network Traffic

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Solution Overview

Problem

Conventional license exchange techniques for media content encryption and decryption result in excessive network traffic and latency due to the need for multiple content key requests for each media track, especially in environments with unreliable network connections, as devices must repeatedly request and receive unique content keys for each track within a movie.

Innovation Solution

Implementing a group license mechanism where all media content within a license group is encrypted with a unique content key derived from a master key, allowing devices to retrieve the master key and derive content keys for decryption, thereby reducing the need for multiple key requests and minimizing network traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional license exchange techniques are used where devices request unique content keys for each media track, then each track can be securely decrypted, but network traffic increases and latency increases

Engineering Contradiction:
Improvecontent decryption securityVSAvoidnetwork traffic
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent merges multiple content keys into a single master key that can derive all individual content keys. Instead of transmitting separate content keys for audio tracks, video tracks, and other media components, the system transmits one master key that the device uses to locally derive all necessary content keys, thereby reducing network traffic while maintaining decryption security.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The master key serves multiple functions: it can derive content keys for different media tracks (audio, video, subtitles), it can protect multiple encrypted content streams, and it eliminates the need for separate key management for each track type. This multi-functionality reduces the overall key management overhead and network communication requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If devices request unique content keys for each media track, then each track can be individually decrypted, but latency increases due to repeated requests

Engineering Contradiction:
Improvecontent decryption capabilityVSAvoidlicense acquisition time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary action by providing the master key in advance, which enables the device to locally derive all content keys before playback begins. This eliminates the need for repeated real-time requests during media playback, reducing latency and ensuring smooth playback experience.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The device performs self-service by using the received master key to automatically derive all necessary content keys locally without needing to contact the license server for each track. This self-service mechanism eliminates repeated network requests and reduces latency while maintaining the ability to decrypt multiple media tracks.

Inventive Principle:
Principle #25Self-service

3Reliability

If multiple content keys are transmitted for different media tracks, then each track can be decrypted, but device complexity increases due to key management

Engineering Contradiction:
Improvemedia content decryptionVSAvoidkey management system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the key management complexity from the network communication layer and places it locally in the device. By receiving a single master key and performing local derivation of content keys, the system eliminates the need for complex network-based key management protocols and reduces device complexity related to key exchange and synchronization.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3350737B1Group license encryption and decryption
Publication Date: 2025.03.26 GOOGLE LLC
  • EP3350737B1 patent drawingFigure 1
  • EP3350737B1 patent drawingFigure 2~3
  • EP3350737B1 patent drawingFigure 4

AI summary

According to an aspect, a computing device may include a media content handler to obtain media content, a group license manager to determine whether or not the media content is part of a license group, and when the media content is determined as part of the license group, the group license manager may determine whether a master key for the license group was previously received. The group license manager may send, over a network, a license request to a license manager when the master key was not previously received. The group license manager may receive, over the network, a license to permit access to the media content, where the license includes the master key. The computing device may include a key generator to derive a content key based on the master key, and a decryption unit to decrypt the media content using the derived content key.