Secure Descrambler Key Transfer via Extraction and Intermediary Logic

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Solution Overview

Problem

Current conditional access systems for digital content are vulnerable to hacking, allowing unauthorized access and copying of digital content, which costs content providers significantly due to the manipulation of messages and descrambling keys being copied and shared.

Innovation Solution

A secure descrambler system that encrypts and decrypts descrambling keys within a dedicated hardware circuit, preventing exposure and ensuring only authorized devices can access and decrypt content, using a unique key stored in non-volatile memory that cannot be hacked or overwritten.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional conditional access systems use smart cards and cryptographic processors to enable content access, then content delivery functionality is improved, but security against hacking deteriorates as descrambling keys can be copied and messages manipulated

Engineering Contradiction:

Improvecontent delivery functionalityVSAvoidsecurity against hacking

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts the descrambling key from the smart card and transfers it to a secure register within the set-top box, where it is protected from external access. This separation isolates the key from potential hacking vectors while maintaining content delivery functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a secure key transfer mechanism that acts as an intermediary between the smart card and the descrambler. This intermediary ensures that the key is transmitted through encrypted channels and stored in protected memory, preventing direct exposure to potential attackers.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If descrambling keys are transferred in clear format for real-time viewing, then content playback functionality is improved, but vulnerability to copying and unauthorized access increases

Engineering Contradiction:

Improvereal-time content playbackVSAvoidunauthorized copying and access

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary encryption of the descrambling key before transfer and implements security checks before key usage. The key is encrypted during transfer and only decrypted in the secure environment of the set-top box, preventing unauthorized interception and copying.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses encryption as a protective shell around the descrambling key during transfer and storage. This cryptographic shell allows the key to be transmitted and stored while remaining inaccessible to unauthorized parties, enabling real-time playback without exposing the key to copying risks.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS7711115B2Descrambler

Publication Date: 2010.05.04 SONY GROUP CORP

AI summary

A descrambler adapted as an integrated circuit (IC) according to one embodiment. The descrambler comprises a control word ladder logic to produce, among other data, a control word to descramble incoming scrambled content. The descrambler further comprises copy protection key ladder logic to recover a copy protection key for encrypting descrambled content before subsequent transmission to a digital device.