Endpoint Audio/Video Encryption for Secure Stream Forwarding
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Solution Overview
Problem
Existing audio/video stream transmission methods face security risks due to intermediate downstream devices decrypting and re-encrypting the stream, making them vulnerable to attacks.
Innovation Solution
Generate content keys for specific audio/video streams, encrypting them with unique algorithms, and transmit encrypted streams with embedded encryption description packets, eliminating intermediate decryption and re-encryption, and using different keys for different streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If intermediate downstream devices decrypt and re-encrypt audio/video streams according to HDCP standard, then stream transmission can be achieved through intermediate devices, but security risks increase due to vulnerability to attacks on intermediate devices
Solution Approach 1:
The patent extracts the decryption and re-encryption functions from intermediate downstream devices, eliminating their involvement in key operations. The transmit end performs encryption before transmission, and the receive end performs decryption after reception, completely removing intermediate devices from the security-critical path while maintaining transmission capability through these devices.
Solution Approach 2:
The patent inverts the traditional HDCP workflow where intermediate devices actively decrypt and re-encrypt. Instead, the encryption and decryption operations are performed at the endpoints (transmit and receive ends), and intermediate devices merely forward the already-encrypted stream without accessing plaintext, thus inverting the security model from intermediate-based to endpoint-based security.
2Device complexity
If a single encryption key is used for all audio/video streams, then key management is simplified, but security is reduced because compromise of one key affects all streams
Solution Approach 1:
The patent segments the encryption key system by generating a unique content key for each individual audio/video stream. Instead of using a single master key for all streams, each stream receives its own dedicated content key, ensuring that compromise of one stream's key does not affect security of other streams, while the system manages multiple keys through systematic generation and distribution.
3Adaptability or versatility
If intermediate downstream devices are involved in encryption/decryption processes, then transmission flexibility is improved, but attack surfaces are increased
Solution Approach 1:
The patent introduces an intermediary approach where the encrypted audio/video stream itself acts as the mediator between transmit and receive ends. Intermediate downstream devices handle only the encrypted form without possessing decryption capabilities, effectively making them passive forwarding elements that cannot be exploited for attacks, while transmission flexibility through multiple intermediate devices is preserved.
Data Source
AI summary
An audio/video stream transmission method includes a transmit end that generates a first content key, where the first content key is used to encrypt an audio/video stream in a unicast scenario; and the transmit end generates a first encryption description packet, where the first encryption description packet includes at least one of an identifier of the first content key, an identifier of the transmit end, an encryption algorithm and mode, and first counter information, and the first counter information is high 64 bits of a first counter. The transmit end encrypts a first audio/video packet of a first audio/video stream based on the encryption algorithm and mode using the first content key and the first counter to obtain a first encrypted audio/video packet, and sends a first encrypted audio/video stream including the first encrypted audio/video packet and the first encryption description packet to a first receive end.