Big Brother watching cellphone users

8.45am - By ADRIENNE KOHLER

Many people are unaware they are leaving a digital information trail as they chat or text on their cellphones.

Cellphone call logs, taped conversations and text messages are a major part of the Crown's evidence against four people currently on trial in Auckland for manufacturing and supplying methamphetamines.

Evidence from a cellphone site log was also used to convict Mark Lundy, sentenced to life imprisonment for killing his wife and daughter in Palmerston North in 2000.

The Aucklander asked Vodafone and Telecom what information they retain in their systems.

Both companies emphasise clients' privacy is their highest priority and say they adhere to all privacy laws.

What call information is held?

Both providers retain information on the time, date and duration of the call; the number called and the number making the call, for at least six months. This is for billing.

What about text messages?

Vodafone retains text message content for approximately 24 hours, while Telecom keeps text messages for 7-14 days. Messages can be saved to help police investigations if the correct warrant is issued.

Who has access to information?

Limited numbers staff have access to the data for billing purposes and customer enquiries.

Staff are bound by privacy laws controlling access to and releasing of information.

Law enforcement agencies can request information on cellphone data through appropriate warrants.

Customers can access their personal account information, such as account balances or information that would be included on their bills. To obtain these directly they must be able to pass security checks such as passwords to verify who they are.

Customers can only obtain information about themselves, not other customers, and not family members.

Can they trace where you are?

Cellphone sites peppered around the country identify where a customer started and ended their call. This information is determined by the cellsites the mobile is currently connected to, or was most recently connected to (providing the mobile is switched on).

Can your cell phone conversation be listened to?

Vodafone advises when the police have served them with an interception warrant, mobile calls can be intercepted. Vodafone has firewalls to prevent unauthorised access.

Telecom says Digital CDMA secured spectrum technology makes it virtually impossible for a conversation to be scanned by a third party. Specific access can be provided to scan calls in appropriate instances or when required by law.

- THE AUCKLANDER