Lawful Interception Interfaces

Everything about Lawful interception:

• Lawful interception requirements
• Lawful interception architecture
• Lawful Interception Interfaces
• X1, X2 and X3 interfaces
• HI1, HI2, and HI3 interfaces
• Standards in Lawful Interception
• Implementation and deployment

Lawful interception requirements

Lawful interception (LI) requires that service providers enable the capture of communications only when authorized by appropriate legal authorities, such as law enforcement agencies (LEAs), under specific conditions defined by law. Interception systems must ensure the secure and accurate collection of both metadata and content of communications, complying with legal standards for privacy and data protection. The system must provide real-time access or on-demand capabilities for LEAs to monitor and analyze the data, ensuring it is delivered securely to authorized entities. It must support auditing and accountability, allowing proper documentation of interception activities for legal and regulatory compliance. Additionally, the interception process should respect time limits and scope constraints set by judicial or governmental oversight to prevent abuse and safeguard civil liberties.

Lawful interception architecture

The architecture involves a structured system for monitoring communications in compliance with legal requirements. It consists of interception points within the service provider's network, where communication data is captured and processed. These intercepted communications (content and metadata) are securely transmitted through defined interfaces (X interfaces and handover interfaces) to authorized law enforcement agencies (LEAs) or monitoring centers. The system ensures real-time or on-demand access for LEAs to the intercepted data, allowing them to analyze communications in an authorized manner. It also includes measures to maintain data integrity and privacy protection while adhering to national and international interception regulations.

Lawful Interception Interfaces

LI Interfaces are defined communication points used in telecommunications and internet systems to facilitate the monitoring of communications by law enforcement agencies (LEAs) in compliance with legal requirements. These interfaces ensure that intercepted data is captured, delivered, and processed securely, while respecting privacy and regulatory guidelines.

The X interfaces and HI (Handover Interface) interfaces are key components of this process, ensuring seamless communication between service providers and law enforcement agencies.

X1, X2, X3 Interfaces manage the interception and transmission of intercepted communication data. The X Interfaces operate at the (mobile) network elements, deals with the physical and logical interception of communication and handling of private communications.

Handover Interfaces (HI1, HI2, HI3) enable triggering interception requests, delivering intercepted data and managing the entire interception process. The HI Interfaces operate more on the administrative and management layer and deal more with the legal compliance matters.

X1, X2 and X3 interfaces

The X1, X2, and X3 interfaces refer to specific communication points between the involved entities (service providers, law enforcement, and network systems) during the interception process. These interfaces ensure private communication and are defined by standards like ETSI (European Telecommunications Standards Institute) and used to ensure proper handling of intercepts in compliance with legal requirements

Here’s an outline of their functions:
X1: Links LEAs to the interception system, enabling request and management of interceptions.
X2: Transmits the intercepted data from the service provider’s system to the LEAs.
X3: Relays data to final monitoring or storage systems, ensuring compliance with legal requirements.

X1 Interface
The X1 interface connects the law enforcement agencies (LEAs) to the Service Provider’s Interception Access Point (IAP). It is used to request interception and deliver the required surveillance information to the authorized parties.
Key Role: It handles the communication that allows law enforcement to initiate, stop, or modify interception requests. This interface is vital for the management of surveillance tasks in real time.
Data Handling: The interface allows LEAs to retrieve metadata (e.g., call details, durations, etc.) and content data (e.g., voice or internet data) subject to interception.

X2 Interface:
The X2 interface connects the interception system (typically owned by the service provider) to the lawful interception monitoring facilities. This is where the interception data from the targeted user is sent to the monitoring center.
Key Role: The X2 interface is responsible for transmitting intercepted data (both content and associated metadata) securely from the network to the monitoring agency in accordance with legal and regulatory requirements.
Data Handling: It handles the actual transport of intercepted communications, including voice, video, and internet traffic (IP data, emails, etc.).

X3 Interface:
The X3 interface is typically used for communication between the service provider's lawful interception system and the mediation or collection system. This allows further processing and handling of the intercepted data.
Key Role: It ensures that intercepted data is properly formatted and routed to the appropriate monitoring facilities, often used for storage, analysis, and compliance with legal frameworks.
Data Handling: It can be involved in the final relay of intercepted data from the service provider’s infrastructure to the relevant legal authorities or storage systems.

HI1, HI2, and HI3 interfaces

The HI1, HI2, and HI3 interfaces refer to specific points of communication between law enforcement agencies (LEAs), service providers, and interception systems like the mediation device. The handover interface is defined by standards like ETSI (European Telecommunications Standards Institute) and the primary goal is to facilitate the lawful monitoring of communications as per legal requirements, ensuring that the process is secure, controlled, and auditable.

Here’s an outline of the handover interfaces and there functions:
HI1: Connects LEAs to the interception system of the service provider for controlling and managing interception operations (requesting and modifying intercepts).
HI2: Delivers intercepted data from the service provider’s interception system to a mediation or monitoring center, where it is collected for analysis.
HI3: Provides LEAs with access to the intercepted data stored or processed in the mediation/monitoring center, allowing them to view, analyze, and act on the information.

HI1 Interface
The HI1 interface is the communication link between the law enforcement agencies (LEAs) and the interception systems of the telecommunication service providers.
Key Role: It allows LEAs to request, manage, and control interception activities. This includes actions such as initiating, modifying, or terminating surveillance on a target, monitoring interception status, and verifying compliance.
Data Handling: HI1 handles the commands and requests from LEAs to the service provider’s interception system. These commands include instructions for intercepting specific communications or data from a targeted individual or communication service.

HI2 Interface
The HI2 interface connects the interception system of the service provider to a mediation or monitoring center (which could be operated by LEAs or third-party authorized agents).
Key Role: This interface is responsible for delivering the intercepted communication data (including both metadata and content) from the interception system to the monitoring or collection system where LEAs can analyze the intercepted information.
Data Handling: HI2 is used to transfer the actual intercepted communications, including voice, video, and internet data, as well as metadata such as call records and other contextual information.

HI3 Interface
The HI3 interface is the communication link between the mediation/monitoring center and the law enforcement agencies (LEAs).
Key Role: This interface allows LEAs to access, review, and manage the intercepted data from the monitoring center. It facilitates the delivery of surveillance information to the relevant legal authorities who have the authorization to access the data for investigation or prosecution purposes.
Data Handling: HI3 is primarily used for providing LEAs with access to the intercepted data, including both the content (e.g., recordings) and metadata (e.g., logs, transaction details) of communications.

Standards in Lawful Interception

Standards are established frameworks and protocols which make sure that interception of data is done in a consistent, secure and legal way. Key standards and organizations involved in the LI Framework are the following:

ETSI - The European Telecommunications Standards Institute (ETSI) develops standards supporting international requirements for law enforcement officials, including the interception and retention of electronic communications data.

Key standards of ETSI are:

• ETSI TS 101 671: focussing on authorization, content delivery and management of HI)
• ETSI TS 102 232 Series: focussing on the interception of information from internet service providers, such as VoIP, email and IP-based communication
• ETSI TS 102 656: focussing on requirements to legally and securely storing communication data

3GPP - 3GPP (3rd Generation Partnership Project) Standards focus on mobile telecommunications standards, such as interception for GSM, UMTS, LTE and 5G networks.

Key standards of 3GPP are:

• 3GPP TS 33.107 and TS 33.108: focussing on requirements for GSM and UMTS
• 3GPP TS 33.126: focussing on the interception of 5G networks including enhanced data collection and real-time monitoring

The Handover Interface (HI) between the mediation device and the government agencies has been standardized by ETSI and 3GPP.

CALEA - CALEA (Communications Assistance for Law Enforcement Act - USA) is a U.S. federal law which mandates telecommunications carriers to support interception capabilities. It specifies requirements for network operators to provide real-time and secure interception and defines standards for VoIP and broadband internet communications.

Implementation and deployment

Lawful Interception is a complicated matter. The implementation and deployment requires careful planning and coordination between the involved parties. Complying to all standards of interfaces requires knowledge in the field, technical solutions and understanding the roles and importance of different stakeholders.

Proper installation of network elements, such as switches and routers, play a crucial role in interception. This way the the network operator collects and provides intercepted communications to law enforcement agencies through the mediation device.

The mediation device must be installed and configured correctly to ensure the secure transfer of intercepted communications. This also requires ongoing maintenance and support to ensure that the system remains secure and effective. Group 2000 is there to help you with these challenges.