5 November 1999. Thanks to A.
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International Law Enforcement
Telecommunications Seminar (ILETS)
(This document is reproduced in electronic form from hard copy)
In many countries worldwide, national laws allow law enforcement agencies to intercept the telecommunications traffic of specific persons under certain conditions. The ability of these agencies to lawfully intercept telecommunications is an invaluable investigative tool that must be preserved. This document presents the requirements of law enforcement agencies to conduct lawful interception of telecommunications services. The objectives of the document are:
- To serve as a harmonised set of international interception requirements, which can be used in the development of national policies
- To increase awareness of law enforcement's interception needs in many countries
- To provide guidance to telecommunications network operators, service providers and manufacturers for meeting interception obligations
- To stimulate the development of telecommunications industry standards for fulfilling interception orders and to ensure that technical standards do not frustrate interception orders.
A. The primary mission of law enforcement agencies is to enforce the laws of their respective jurisdictions. These laws relate to criminal investigations as well as the protection of national security and other national interests. In many countries, national laws allow government agencies under certain conditions to intercept the telecommunications traffic of specific persons. Generally, law enforcement agencies conduct court ordered or otherwise authorised interception when other investigative techniques are determined insufficient or too dangerous. This extraordinary technique is critical to the mission of law enforcement agencies.
B. To conduct lawful surveillance of telecommunications, law enforcement agencies need access to the communications associated with the targets of investigation. In this process, law enforcement agencies rely on the cooperation and assistance of operators of communications networks, providers of communications services, and manufacturers of communications equipment. Furthermore, it is necessary that the telecommunications systems are technically capable of supporting lawful authorisations to intercept communications. The telecommunications industry should accommodate interception requirements in accordance with national policies during the development of new technologies and services. This cost effective approach will help ensure that lawful interceptions can be performed in a timely and efficient manner.
C. Recent and continuing advances in telecommunications technologies and services challenge, and at times erode the ability of law enforcement agencies to fully implement lawful authorisations to intercept communications. Trends in wireline (fixed) and wireless (mobile) communications technologies are leading to an environment where subscribers are offered ubiquitous, uninterrupted communications capability as they move freely from service area to service area, identified by a single personal telecommunications number, data network address, or similar identifier. Law enforcement agencies throughout the world are seeking the continued cooperation of network operators, service providers and manufacturers to meet the challenges posed to interception by emerging and future technologies. Law enforcement agencies do not seek to impede the evolution of telecommunications, rather they are trying to preserve interception capabilities.
A. This document presents the requirements of law enforcement agencies throughout the world to effectively and fully conduct telecommunications interception. Law enforcement representatives and government telecommunications experts from a number of countries that attended an international workshop on interception and advanced telecommunications technologies identified the need for this document. These requirements can be used by law enforcement agencies, national telecommunications authorities, national legislative bodies, and international standards organisations in discussions with the telecommunications industry on fulfilling interception orders. The requirements may also serve as a planning aid for the network operators, service providers, and equipment manufacturers.
B. The requirements are intended to set out key elements needed for the technical and operational implementation of lawful interceptions of telecommunications. The requirements are not specific to any existing or future communications technology, equipment or service. In addition, these requirements will have to be considered in the context of specific national legal, technical, operational and tactical requirements. This means that the requirements can neither be all-inclusive nor final.
1.3 Document Organisation and Maintenance
A. The remainder of this document is organised into two sections. Section 2 states the interception requirements of law enforcement agencies. The order in which the requirements appear does not reflect their relative importance or sequence for the purpose of implementation. Section 3 contains a glossary of key words and phrases used in the requirements. Due to the continuing evolution of telecommunications technology, this document will be reviewed periodically and updated as needed.
This section presents the Requirements of law enforcement agencies relating to the lawful interception of telecommunications. These requirements are subject to national law and should be interpreted in accordance with applicable national policies.
Terms are defined in the attached glossary.
1.0 Law enforcement agencies require access to the entire telecommunications transmitted, or caused to be transmitted, to and from the number or other identifier of the target service used by the interception subject. Law enforcement agencies also require access to the call-associated data that are generated to process the call.1.1 Law enforcement agencies require access to all interception subjects operating temporarily or permanently within a telecommunications system.
1.2 Law enforcement agencies require access in cases where the interception subject may be using features to divert calls to other telecommunications services or terminal equipment, including calls that traverse more than one network operator/service provider before completing.
1.3 Law enforcement agencies require that the telecommunications to and from a target service be provided to the exclusion of any telecommunications that do not fall within the scope of the interception authorisation.
1.4 Law enforcement agencies require access to call associated data such as:1.4.1 Signalling of access ready status
1.4.2 Called party number for outgoing connections even if there is no successful connection established
1.4.3 Calling party number for incoming connections even if there is no successful connection established
1.4.4 All signals emitted by the target, including post-connection dialled signals emitted to activate features such as conference calling and call transfer
1.4.5 Beginning, end and duration of the connection
1.4.6 Actual destination and intermediate directory number if call has been diverted
1.5 Law enforcement agencies require information on the most accurate geographical location known to the network for mobile subscribers.
1.6 Law enforcement agencies require data on the specific services used by the interception subject and the technical parameters for those types of communication.
2.0 Law enforcement agencies require a real-time, full-time monitoring capability for the interception of telecommunications. Call associated data should also be provided in real-time. If call associated data cannot be made available in real-time, law enforcement agencies require the data to be available as soon as possible upon call termination.
3.0 Law enforcement agencies require network operators/service providers to provide one or several interfaces from which the intercepted communications can be transmitted to the law enforcement monitoring facility. These interfaces have to be commonly agreed on by the interception authorities and the network operators/service providers. Other issues associated with these interfaces will be handled according to accepted practices in individual countries.3.1 Law enforcement agencies require network operators/service providers to provide call associated data and call content from the target service in a way that allows for the accurate correlation of call associated data with call content.
3.2 Law enforcement agencies require that the format for transmitting the intercepted communications to the monitoring facility be a generally available format. This format will be agreed upon on an individual country basis.
3.3 If network operators/service providers initiate encoding, compression or encryption of telecommunications traffic, law enforcement agencies require the network operators/service providers to provide intercepted communications en clair.
3.4 Law enforcement agencies require network operators/service providers to be able to transmit the intercepted communications to the law enforcement monitoring facility via fixed or switched connections.
3.5 Law enforcement agencies require that the transmission of the intercepted communications to the monitoring facility meet applicable security requirements.
4.0 Law enforcement agencies require interceptions to be implemented so that neither the interception target nor any other unauthorised person is aware of any changes made to fulfil the interception order. In particular, the operation of the target service must appear unchanged to the interception subject.
5.0 Law enforcement agencies require interception to be designed and implemented to preclude unauthorised or improper use and to safeguard the information related to the interception.5.1 Law enforcement agencies require network operators/service providers to protect information on which and how many interceptions are being or have been performed, and not disclose information on how interceptions are carried out.
5.2 Law enforcement agencies require network operators/service providers to ensure that intercepted communications are only transmitted to the monitoring agency specified in the interception authorisation.
5.3 According to national regulations, network operators/service providers could be obliged to maintain an adequately protected record of activations of interceptions.
6.0 Based on a lawful inquiry and before implementation of the interception, law enforcement agencies require (1) the interception subject's identity, service number or other distinctive identifier, (2) information on the services and features of the telecommunications system used by the interception subject and delivered by network operators/service providers, and (3) information on the technical parameters of the transmission to the law enforcement monitoring facility.
7.0 During the interception, law enforcement agencies may require information and/or assistance from the network operators/service providers to ensure that the communications acquired at the interception interface are those communications associated with the target service. The type of information and/or assistance required will vary according to the accepted practices in individual countries.
8.0 Law enforcement agencies require network operators/service providers to make provisions for implementing a number of simultaneous intercepts. Multiple interceptions may be required for a single target service to allow monitoring by more than one law enforcement agency. In this case, network operators/service providers should take precautions to safeguard the identities of the monitoring agencies and ensure the confidentiality of the investigations. The maximum number of simultaneous interceptions for a given subscriber population will be in accordance with national requirements.
9.0 Law enforcement agencies require network operators/service providers to implement interceptions as quickly as possible (in urgent cases within a few hours or minutes). The response requirements of law enforcement agencies will vary by country and by the type of target service to be intercepted.
10.0 For the duration of the interception, law enforcement agencies require that the reliability of the services supporting the interception at least equals the reliability of the target services provided to the interception subject. Law enforcement agencies require the quality of service of the intercepted transmissions forwarded to the monitoring facility to comply with the performance standards of the network operators/service providers.
Access The technical ability to interface with a communications facility, such as a communications line or switch, so that a law enforcement agency can acquire and monitor communications and call associated data carried on the facility.
Call Any connection (fixed or temporary) capable of transferring information between two or more users of a telecommunications system.
Call Associated Data Signalling information passing between a target service and the network or another user. Includes signalling information used to establish the call and to control its progress (eg call hold, call handover). Call associated data also includes information about the call that is available to the network operator/service provider (eg duration of connection).
Interception As used here, the statutory based action of providing access and delivery of a subject's telecommunications and call associated data to law enforcement agencies.
Interception Interface The physical location within the network operator's/service provider's telecommunications facilities where access to the intercepted communications or call associated data is provided. The interception interface is not necessarily a single, fixed point.
Interception Order An order placed on a network operator/service provider for assisting a law enforcement agency with a lawfully authorised telecommunications interception.
Interception Subject Person or persons identified in the lawful authorisation and whose incoming and outgoing communications are to be intercepted and monitored.
Law Enforcement Agency A service authorised by law to carry out telecommunications interceptions.
Law Enforcement Monitoring Facility A law enforcement facility designated as the transmission destination for the intercepted communications and call associated data for a particular interception subject. The site where monitoring/recording equipment is located.
Lawful Authorisation Permission granted to a law enforcement agency under certain conditions to intercept specified telecommunications. Typically this refers to an order or warrant issued by a legally authorised body.
Network Operator/Service Provider "network operator" = the operator of a public telecommunications infrastructure which permits the conveyance of signals between defined network termination points by wire, by microwave, by optical means or by other electromagnetic means; and
"service provider" = the natural or legal person providing (a) public telecommunications service(s) whose provision consists wholly or partly in the transmission and routing of signals on a telecommunications network.
Quality of Service The quality specification of a communications channel system, virtual channel, computer-communications session, etc. Quality of service may be measured, for example, in terms of signal-to-noise ratio, bit error rate, message throughput rate, or call blocking probability.
Reliability The probability that a system or service will perform in a satisfactory manner for a given period of time when used under specified operating conditions.
Roaming The ability of subscribers of mobile telecommunications services to place, maintain, and receive calls when they are located outside their designated home serving area.
Target Service A service associated with an interception subject and usually specified in a lawful authorisation for interception
Telecommunications Any transfer of signs, signals, writing, images, sounds, data or intelligence of any nature transmitted in whole or in part by a wire, radio, electromagnetic, photoelectronic, or photooptical system.
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