Secure RTP Media Key Exchange via Authenticated Signaling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Internet telephony systems face security challenges due to the ease of eavesdropping on RTP media sessions in packet-switched networks, and existing encryption methods are cumbersome, costly, or require asymmetric encryption and digital certificates, which are inefficient for large-scale RTP endpoint environments.
Innovation Solution
A method for establishing a shared secret media key between RTP endpoints using Diffie-Hellman key agreement and authentication hash algorithms, eliminating the need for digital certificate distribution and asymmetric encryption, ensuring secure RTP media sessions without middle-man attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If symmetric encryption is used to secure RTP media sessions, then security against eavesdropping is improved, but key distribution becomes vulnerable to middle-man attacks
Solution Approach 1:
The patent applies preliminary action by establishing authenticated signaling sessions before exchanging Diffie-Hellman parameters. The signaling messages are authenticated using hash algorithms and shared secret authentication keys, which are established in advance through secure provisioning. This preliminary authentication prevents middle-man attacks by ensuring that the DH parameter exchange occurs within an already authenticated channel.
Solution Approach 2:
The patent uses an intermediary approach by introducing authenticated signaling sessions as a mediator between the RTP endpoints. The signaling channel, protected by authentication mechanisms, serves as an intermediary that enables secure key exchange without requiring direct trust between endpoints or vulnerable key distribution infrastructure.
2Reliability
If asymmetric encryption and digital certificates are used for mutual authentication and key exchange, then security against middle-man attacks is improved, but processing power requirements and system cost increase significantly
Solution Approach 1:
The patent extracts the heavy asymmetric encryption requirement from the key exchange process. Instead of using asymmetric encryption for the actual key exchange, the patent uses it only for initial authentication of the signaling channel, then relies on symmetric encryption for the media session key exchange. This extraction reduces processing power requirements while maintaining security.
Solution Approach 2:
The patent employs cheap, short-lived symmetric encryption keys for the media session instead of expensive, long-lived asymmetric key pairs. The symmetric keys are generated fresh for each session and discarded afterward, providing adequate security without the computational overhead of asymmetric cryptography during the media transmission phase.
3Adaptability or versatility
If asymmetric encryption algorithms are implemented in RTP endpoints, then mutual authentication capability is improved, but circuit cost and implementation complexity increase
Solution Approach 1:
The patent segments the authentication and key exchange functions into separate phases. The complex asymmetric authentication is performed only during the initial signaling phase, while the media session uses simpler symmetric key exchange. This segmentation allows RTP endpoints to have reduced functionality for media handling while relying on the authenticated signaling channel for security.
Solution Approach 2:
The patent substitutes mechanical asymmetric encryption hardware in RTP endpoints with a software-based authenticated signaling system. The authentication logic is moved to the signaling layer, allowing RTP endpoints to use simpler circuits that rely on software-based authentication rather than dedicated asymmetric encryption hardware.
Data Source
AI summary
A system and method for establishing a shared secret media key between each of a caller endpoint and a callee endpoint for securing a real time media channel comprises: i) establishing a caller authenticated signaling session with the caller endpoint using a caller shared secret authentication key and a symmetric encryption algorithm; and ii) establishing a callee authenticated signaling session with the callee endpoint using a callee shared secret authentication key and the symmetric encryption algorithm. A caller public value is received from the caller endpoint through the caller authenticated signaling session and sent to the callee endpoint through the callee authenticated signaling session. The caller public value is a public value of a pair of values generated by the caller endpoint and useful for calculating a shared secret media key. A callee public value is received from the callee endpoint through the callee authenticated signaling session and sent to the caller endpoint through the caller authenticated signaling session. The callee public value is a public value of a pair of values generated by the callee endpoint and useful for calculating a shared secret media key. Both the caller endpoint and the callee endpoint calculate the shared secret media key using Diffie-Hellman techniques.