Call Signal Verification via Out-of-Band Handshake
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Solution Overview
Problem
Current solutions for detecting voice call fraud, such as STIR/SHAKEN, are complex and ineffective in real-time detection and blocking of manipulations like CLI spoofing, short stopping, call stretching, and PBX hacks within interconnected carrier networks.
Innovation Solution
A bi-directional handshake exchange over an encrypted out-of-band channel between originating and terminating call networks verifies the legitimacy of call signals, using call registries to detect discrepancies and generate alerts for fraudulent activities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If STIR/SHAKEN procedures are implemented for detecting call fraud, then detection capability is improved, but system complexity increases and real-time detection is prevented
Solution Approach 1:
The patent extracts the verification logic from complex STIR/SHAKEN procedures into a simplified out-of-band handshake mechanism between call registries. The core verification function is separated from the call signaling path, allowing real-time detection without complex in-band procedures. This extraction enables fraud detection while reducing system complexity by eliminating the need for complex certificate validation and policy checking within the call path.
Solution Approach 2:
The patent introduces call registries as intermediary components that mediate verification between originating and terminating networks. These registries handle the complex verification logic externally, allowing the core call path to remain simple while still achieving reliable fraud detection. The intermediary registries absorb the complexity of verification procedures, enabling real-time detection without burdening the call signaling path.
2Measurement precision
If complex verification procedures are used to verify call signals, then detection accuracy is improved, but processing time increases and real-time blocking is prevented
Solution Approach 1:
The patent performs verification actions preliminarily through out-of-band handshake exchanges between call registries before fraudulent calls are executed. By pre-verifying call signal legitimacy through registry handshakes, the system maintains detection accuracy while enabling real-time blocking. The preliminary verification establishes trust relationships in advance, eliminating the need for time-consuming verification during active call processing.
Solution Approach 2:
The patent replaces traditional in-band mechanical verification procedures with an out-of-band electronic handshake mechanism. This substitution moves verification to a separate communication channel, allowing parallel processing that maintains detection accuracy while dramatically reducing processing time. The electronic registry-to-registry handshake occurs independently of the call path, enabling real-time detection and blocking without delaying call setup.
3Productivity
If call signals are verified in real-time, then fraud blocking effectiveness is improved, but network overhead increases
Solution Approach 1:
The patent extracts verification traffic from the primary call signaling path and relocates it to out-of-band registry handshake channels. This extraction allows real-time fraud blocking effectiveness while reducing network overhead on the call path. The verification exchanges occur separately between registries, minimizing the impact on call processing efficiency and reducing overall network overhead.
Solution Approach 2:
The patent uses call signal copies for verification purposes rather than verifying the original call signals directly. Registries exchange copies of call signal data through out-of-band handshakes, enabling real-time fraud detection and blocking while preserving the original call path for efficient voice transmission. This copying approach maintains blocking effectiveness while reducing network overhead by separating verification traffic from media traffic.
Data Source
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AI summary
A system detects abnormalities in a call signal indicative of call fraud. The system includes a first device situated in an originating call network and configured to send call signals to a second device situated in a terminating call network. The first device is coupled to a first registry to which it sends the call data from the sent signals for storage as originating call records. The second device is coupled to a second registry to which it sends the call data from the received signals for storage as terminating call records. The first and second registries exchange verification requests and responses to detect whether discrepancies exist between the stored originating call records in the first registry and stored terminating call records in the second registry. The registries generate alerts based on detected discrepancies, which may be used by the devices to block the call fraud.