Part 3: Authorisations for obtaining communications data Section 67: Filtering arrangements for obtaining data
This section provides a power to establish filtering arrangements to facilitate the lawful, efficient and effective obtaining of communications data by relevant public authorities and to assist a designated senior officer in each public authority to determine whether he believes the tests for granting an authorisation to obtain data have been met. The filtering arrangements will minimise the communications data obtained, thereby ensuring that privacy is properly protected.
Potential use of the request filter
Example (1): IP address resolution:
An investigator has details of a number of IP addresses which they believe relate to a specific individual, and have been used to access internet services at known times. However, each IP address cannot be resolved to a single individual because at the known time it has been simultaneously shared between many internet users. In this example the request filter would be able to match the specific individual in common between the users of each the IP addresses, then disclose only the communications data about that specific individual to the public authority. Without the request filter telecommunications operators would need to disclose details of every individual that had shared the IP addresses at the relevant times, and an analyst working in the public authority would examine all of the individual’s data to obtain the same result.
Example (2): Location correlation:
If an investigator knows that a person of interest has been in a number of places at certain times. The request filter would enable them to determine whether communications service providers retained information that can identify the specific individual that matched being in those locations. Without the request filter the data of every individual that matched each location would have to be disclosed and the law enforcement agency would need to correlate the data.
	These types of applications, as all communications data applications, would only be able to be made where necessary and proportionate.
	The power to establish filtering arrangements in subsection (1) operates solely in the context of Part 3 of the Act which creates a regulatory regime for obtaining data. The power is intended to facilitate the obtaining of data by public authorities only for the purpose of a specific investigation or a specific operation in accordance with an authorisation, whilst protecting privacy. Any communications data obtained by the filtering arrangements must be immediately deleted once the purposes of the authorisation have been met.