Secure Call Processing via Proxy Intermediary

The patent introduces an intermediary entity (session border controller or switch) that acts as a mediator between the caller and the contact centre. This intermediary intercepts and processes DTMF tones containing sensitive information before they reach the agent, blocking them when necessary while allowing normal call flow when no sensitive information is present. This approach distributes the security function across the network infrastructure rather than requiring a dedicated call processor at the contact centre, thereby reducing device complexity and licensing requirements while maintaining security.

The patent makes the session border controller or switch perform multiple functions: it acts as both a security processing entity for blocking sensitive DTMF tones and as a standard call routing entity for normal call flow. By combining these functions into a single network element that already exists in the telephony infrastructure, the system eliminates the need for separate dedicated security hardware and licensing, thereby reducing costs and improving scalability while maintaining security processing capability.

The patent implements dynamic filtering of DTMF tones based on the call context and content analysis. The session border controller or switch continuously monitors incoming DTMF tones and dynamically determines whether to block or allow each tone based on whether it contains sensitive information. This dynamic approach allows normal menu navigation tones to pass through unblocked while automatically blocking tones that contain sensitive data, thereby maintaining ease of operation for legitimate purposes while ensuring security when sensitive information is transmitted.