Media Encryption Key Transition Using Indicator Flags
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Solution Overview
Problem
During secure media communication sessions, the transition from an expired media encryption key (MEK) to a new MEK can cause media packets to be decrypted with the wrong key, leading to encryption and decryption issues due to network delays and timing discrepancies among participants.
Innovation Solution
Implement a method where the current MEK is replaced with a new MEK before expiration, using a MEK indicator flag (MIF) to determine which key to use for decryption during the key transition period, ensuring seamless encryption and decryption of media streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a new MEK is requested and transitioned before the current MEK expires, then media encryption continuity is improved, but device complexity increases due to key management overhead
Solution Approach 1:
The system requests a new MEK before the current MEK expires, performing the key renewal action in advance. This preliminary action ensures that a valid key is ready before the current key becomes invalid, preventing encryption gaps and maintaining continuous media protection
Solution Approach 2:
The patent introduces an intermediary mechanism (key transition protocol with MIF flags) that mediates the transition between old and new keys. This intermediary system coordinates the key switching process across network participants, ensuring smooth transitions without disrupting media flow
2Measurement precision
If all participants transition to the new MEK simultaneously, then decryption accuracy is improved, but loss of time increases due to network synchronization delays
Solution Approach 1:
The system dynamically adjusts the key transition timing for different participants based on their individual network conditions and reception states. Rather than enforcing a rigid simultaneous transition, each participant transitions when appropriate, with the MIF flag system adapting to varying network delays and participant states
Solution Approach 2:
The patent implements a feedback mechanism where participants send MIF flags indicating their current key usage state. This feedback allows the system to track and coordinate key transitions across the network, ensuring that decryption accuracy is maintained while accommodating natural timing variations
3Measurement precision
If the MEK transition period is extended to allow all participants to switch keys, then decryption accuracy is improved, but productivity decreases due to longer key transition window
Solution Approach 1:
The system uses partial action by employing MIF flags only during the key transition period rather than continuously. This selective use of the indicator mechanism provides sufficient information for accurate decryption during the critical transition window without adding unnecessary overhead during stable operation periods
Data Source
AI summary
The disclosed embodiments provide for methods and apparatus for encrypting media using a current media encryption key (MEK), requesting a new MEK, and receiving the new MEK. The method further provides for transitioning from the current MEK to the new MEK and continuing to encrypt the media using the new MEK. In another embodiment, the method provides for decrypting media during an ongoing media communication session, the method provides for receiving encrypted media, and decrypting the encrypted media using a current MEK. The method further provides for requesting a new MEK before the current MEK expires based on its associated expiration time, receiving the new MEK, and continuing to decrypt the encrypted media based on a received MEK indication flag (MIF) that indicates whether the encrypted media is encrypted using the current MEK or the new MEK.