Multi-Display HDCP Re-Encryption for Secure Image Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-display systems, such as video walls, images encrypted with High-bandwidth Digital Content Protection (HDCP) are vulnerable to decryption and unauthorized copying when transmitted across multiple display devices, as they are decrypted once and then consecutively transmitted, potentially leading to leakage through hacking.
Innovation Solution
A display apparatus with an input connector for receiving HDCP-encrypted images, a processor for decrypting and re-encrypting the images, and an output connector for secure transmission to other display devices, along with a user interface for managing HDCP state information through an auxiliary channel, ensuring that images are only decrypted and re-encrypted as necessary based on user commands or received state information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the encrypted image is decrypted in the first display apparatus and consecutively transmitted to other connected display apparatuses, then the image can be displayed on multiple screens, but the decrypted image may be leaked through hacking during transmission
Solution Approach 1:
The patent extracts the decryption operation from the transmission path by performing decryption only at the final display apparatus rather than at intermediate nodes. This removes the vulnerable decrypted image from the transmission chain, allowing multi-display functionality while eliminating the security risk of transmitted decrypted images being hacked.
Solution Approach 2:
The system performs preliminary encryption maintenance at each display apparatus before transmission. Each apparatus maintains HDCP encryption status and ensures that images remain encrypted during transmission, only decrypting locally at the final display node where they are needed for presentation.
2Object-affected harmful factors
If the image is re-encrypted at each display apparatus before transmission to the next apparatus, then the security of the image is improved, but the device complexity increases
Solution Approach 1:
Each display apparatus autonomously manages its own HDCP encryption status and makes independent decisions about whether to decrypt or re-encrypt images based on its role in the multi-display chain. This self-service approach distributes the processing complexity across multiple devices rather than concentrating it in one central controller, making the system more scalable and reducing single-point complexity.
Solution Approach 2:
The system implements feedback mechanisms where display apparatuses exchange HDCP state information to coordinate encryption/decryption decisions. This feedback loop allows devices to understand their position in the transmission chain and make appropriate encryption decisions without requiring complex centralized control logic.
3Reliability
If the HDCP state information is transmitted through the auxiliary channel, then the security management is improved, but the communication protocol complexity increases
Solution Approach 1:
The patent utilizes the existing auxiliary channel of the DisplayPort interface for dual purposes: both for standard DisplayPort communication functions and for transmitting HDCP state information. This multi-functional use of the auxiliary channel avoids adding separate dedicated communication hardware or protocols, thereby improving HDCP state management reliability while minimizing increases in overall system complexity.
Data Source
AI summary
A display apparatus of a multi-display system is disclosed. The display apparatus includes a display, an input connector configured to receive an input of an image which is encrypted based on HDCP, an output connector which is connected with another display apparatus of the multi-display system, and a processor configured to control the display to display an image corresponding to the display apparatus by decrypting the encrypted image and to re-encrypt the decrypted image to transmit to the another display apparatus through the output connector.