Automated Spam Call Traceback: Two Efficiency Enhancement Approaches

Spam calls have been a persistent issue, leading to significant economic and social harm. Spam call traceback is a crucial measure to combat spam calls by identifying fraudsters and holding problematic providers accountable. An automated spam call traceback method, i.e., Jager, was proposed to address low efficiency issues of manual traceback. However, apart from complex cryptographic operations, it requires traceback authority (TA) to generate a call label for every call, and all the call detail records (CDRs) are required to be stored at a central server. These generates very high and unnecessary traffic and computation loads. In this paper, we first investigate a simple automated spam call traceback method, namely distributed CDR sharing (DCS).With this method the carriers grant access of their local CDRs to an automated call traceback center (ACTC). The ACTC only accesses the CDRs for reported spam calls via secure APIs. The call path can be automatically reconstructed to locate the spam call origins. As non-cooperative carriers (such as legacy and malicious carriers) may break the traceback automation, we propose an enhanced automated spam call tracing (ASCT) method to address the issue. ASCT uses locally stored chained CDR blocks for mutual verification between carriers. Only when non-cooperative carriers are encountered, copies of CDRs are send to a central CDR server to help mitigate the impact of the non-cooperative carriers. The proposed methods are evaluated and compared to the manual and Jager methods. Experiment results show that the proposed methods are very efficient and scalable, while achieving a similar level of security performance to that of the manual method. Under the condition of all cooperative carriers, full call tracing automation can be achieved without generating any traffic to the central CDR server.