# An SSI-Based Solution to Support Lawful Interception
## 8 Conclusions and Future Work  
In this paper, we proposed an SSI-based solution to implement an access control mechanism that supports a LI procedure. Our proposal is motivated by the need to overcome the absence of a standard for the interactions between the LEA and LEMF. In the design of the solution, we followed the guidelines of the Sovrin framework. In particular, we adopted the SSI stack, which defines how trust is achieved among several participants. To make our proposal more concrete, we provided a proof of concept using standard and well-consolidated technologies, which allowed us to verify that our proposal is technically feasible. The findings of this research show that an SSI-based solution can enhance security, automation, and interoperability in lawful interception procedures. Our proposal research defines how access control mechanisms in lawful interceptions can be strengthened, ensur  
Figure 10: Indy Scan. ing that only authorized entities, specifically law enforcement agencies or external agencies, can retrieve intercepted data. This is particularly important in cross-border investigations, where secure access to intercepted communications is often hindered by differences in interception procedures across countries. Our solution eliminates the manual operations of traditional lawful interceptions, which are substituted by machine-readable procedures. This change reduces human error and improves efficiency by accelerating all the processes related to lawful interception. Moreover, the use of verifiable credentials mitigates the risks associated with centralized identity providers, reducing single points of failure and enhancing privacy through selective disclosure. By addressing the lack of standardized interaction protocols between LEA and LEMF, this research introduces a more secure and privacy-preserving approach to lawful interception and defines workflows for all involved entities, with the aim of improving investigative capabilities and enhancing legal compliance. Alongside the advantages discussed above, our proposal presents some limitations. The first limitation concerns the adoption. Indeed, SSI is an emerging paradigm, which lacks widespread adoption and does not benefit from the sponsorship of major organizations (like Google and Facebook, which support federated identity). Moreover, the lack of uniform regulation regarding the use and validity of SSI makes legal compliance challenging, particularly in law enforcement, where adherence to legal frameworks is critical. Considering the eIDAS Regulation, although it is focused on government eIDs and does not integrate SSI, the success of blockchain convinced the EU Commission to revise regulations to consider the SSI paradigm [72]. Another limitation of our proposal concerns the introduction of operational costs. Since operations done on the blockchain require the payment of a transaction fee, this may change the business model. In our solution, each operation, such as credential issuance or verification, involves a blockchain transaction and incurs a small fee (usually around a few dollar cents), which is not necessary for traditional lawful interceptions. However, we expect that transaction fees introduced by our solution will be negligible compared to the overall costs incurred by organizations for lawful interception, as these expenses are primarily driven by infrastructure and human activity rather than identity and access control verification processes. Exploring these aspects is a natural progression of this research. As further future work, we plan to integrate the SSI approach also in the interaction between the LEMF and the network operator. In particular, the technical parameters needed to start the LI procedure can be exchanged in the form of credentials through the peer-to-peer channels offered by the SSI approach. In other words, these channels may replace the HI1 management interface defined by the ETSI standard [10]. Methodology, A.L.C., F.B., V.D.A. and A.L. ; software, A.L.C. and A.L.