Privileged Memory Arbitration for Video Processing Security
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Solution Overview
Problem
Current security systems for video processing devices, particularly those using system on a chip (SOC) technology, face vulnerabilities due to shared processor and memory spaces, asynchronous cryptographic client requests, and the risk of key attacks, leading to potential unauthorized access and revocation of secret keys.
Innovation Solution
A security device architecture that includes a privileged memory access system with an arbitration module to manage cryptographic key access, using one-time programmable memory and rule sets to enforce strict access controls, ensuring only authorized requests are granted access to cryptographic keys and operations, thereby preventing unauthorized access and key attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OTP memory is used to store secret keys, then security against unauthorized access is improved, but vulnerability to key attacks through block-by-block access worsens
Solution Approach 1:
The patent divides cryptographic keys into multiple separate blocks stored in OTP memory, each block being individually protected. This segmentation prevents attackers from accessing complete key values through block-by-block reading, as each block alone is insufficient for cryptographic operations.
Solution Approach 2:
The patent introduces an arbitration module as an intermediary between cryptographic clients and OTP memory. This mediator enforces access rules that prevent direct block-by-block reading of key blocks, allowing only authorized cryptographic operations to access key material through controlled interfaces.
2Adaptability or versatility
If multiple cryptographic clients access OTP memory asynchronously, then operational flexibility is improved, but security control and atomicity of operations worsen
Solution Approach 1:
The arbitration module serves as a mediator that manages asynchronous access requests from multiple cryptographic clients. It enforces atomicity rules ensuring that key access operations are completed indivisibly, preventing security vulnerabilities from partial or interleaved access to key blocks.
Solution Approach 2:
The patent establishes access rules and arbitration mechanisms in advance before cryptographic operations begin. These pre-configured security policies control how multiple clients can access OTP memory, ensuring atomicity and proper synchronization without requiring complex runtime negotiations.
3Adaptability or versatility
If large cryptographic keys are partitioned into small blocks, then storage flexibility is improved, but the need for granular access control rules increases complexity
Solution Approach 1:
The arbitration module implements universal access control rules that apply to all cryptographic clients and key blocks uniformly. Rather than creating unique granular rules for each client-block combination, the system uses generalized policies that manage access to partitioned key material across multiple clients, reducing overall rule complexity.
4Adaptability or versatility
If video processing hardware shares processor and memory space with user applications, then device integration is improved, but security vulnerability worsens
Solution Approach 1:
The patent extracts cryptographic key storage and access control into a separate, protected domain using OTP memory and an arbitration module. This isolation removes sensitive key material from the shared processor and memory space accessible to user applications, creating a secure enclave that prevents application-level access while maintaining device integration.
Data Source
AI summary
A device includes a key store memory, a rule set memory, a plurality of cryptographic clients, and a key store arbitration module. The key store memory stores a plurality of cryptographic keys and the rule set memory stores a set of rules for accessing the cryptographic keys. A cryptographic client is operable to issue a request to access a cryptographic key(s) and, when access to the cryptographic key is granted, execute a cryptographic function regarding at least a portion of the cryptographic key to produce a cryptographic result. The key store arbitration module is operable to determine whether the request to access the cryptographic key is valid; when the request is valid, interpret the request to produce an interpreted request; access the rule set memory based on the interpreted request to retrieve a rule of the set of rules; and grant access to the cryptographic key in accordance with the rule.