Securing RTP packets using persistent packet key encryption scheme for real-time multimedia applications

Most of the existing encryption methods use the same key to secure different RTP payloads during a given session. However, the use of the session key cannot guarantee protection against brute force attacks that can be done after transmission using the captured RTP data for the realtime multimedia streams. This paper deals with the packet key methods where Diffie-Hellman key exchange procedures repeat only for the RTP packets that are selected based on the key change rate. This paper proposes a persistent packet key encryption scheme that uses the same packet key for a certain period and changes the key for the next period. The key change schedule is controlled by the key change rate. The persistent packet key encryption scheme aims to improve latency for encryption and decryption compared with the full packet key encryption scheme where the packet key changes every packet. The main goal of this paper is to propose the packet key scheme that is significantly more secure than the session key scheme while satisfying the latency requirements for the real-time multimedia transmission.