Data retention legislation is wrong on fundamental grounds. Governments are supposed to serve the people, not treat them as presumptive criminals, writes David Leyonhjelm.

A bill currently working its way through Parliament will, if enacted, require internet service providers to store every Australians' personal digital history so that law enforcement officers can access it without a warrant.

When governments get involved in regulating things they don't understand, things tend to go terribly wrong. Getting into the insulation business, for instance, resulted in installers dying and houses burning down. This proposal has the potential to have equally significant consequences.

The information to be stored is known as metadata, and there are three major areas of concern with requiring its retention: how will it be used, how much will it cost to store, and who will foot the bill.

There is also a problem with the definition, not least with our Attorney-General. An entire battalion of legal types was unable to come up with a definition for the bill, so it's been left to the regulations. That means it can be easily changed.

The suggestion that it is a little like the name and address on an envelope, to be distinguished from the content, might persuade a few mums and dads but it is not accepted by anyone who knows anything at all about computers.

In reality, your metadata reveals just about anything anyone might want to know about you, at least based on your internet usage. It will reveal, for example, the websites you visited, the people who've emailed you and you've emailed back, where you were while using your phone, the purchases you made, and your Google searches. In the case of the latter three activities, there is actually no difference between 'metadata' and 'content'.

Metadata is produced automatically by the devices we use. While you can control what you say and write, you have no control over what your computer or smartphone does to allow you to do so. This means that if you've ever received a scam email or made a phone call while walking past a brothel or abortion clinic, this can be identified from your metadata.

But for all of the talk about definitions, there is a very simple principle at stake. If it is wrong for a private citizen to snoop on your private information, it ought to be equally wrong for the government to do it.

The Government tells us the data will not be used to chase people who download Game of Thrones or watch porn, and we should trust them because they are the Government. Journalists are told their confidential sources will not be uncovered using this information, because they too can trust the Government. And of course, all future Governments that use these laws can also be trusted.

Then there's the potential for other people to gain access to the data. Privacy breaches are already a regular occurrence even with banks, yet ISPs, which mostly have very little experience at protecting stored data, will be obliged to keep all this information safe for two years.

And the volume of storage required will be massive, amounting to petabytes of data and cloud storage requiring hundreds or thousands of file servers. Almost certainly these will be located in China, where prices are cheapest.

But that does not mean the whole process will actually be cheap. ISPs like iiNet, TPG and iPrimus, along with Telstra and Optus, will be liable for hundreds of millions of dollars in storage costs. Which raises the obvious question - should taxpayers foot the bill or will the costs be passed on to customers?

In either case, anyone who uses the internet will pay for the privilege of being spied on. That includes the personal data of Air Chief Marshall Mark Binskin, Chief of the Defence Force; Duncan Lewis, the head of ASIO; and Prime Minister Tony Abbott. It might be simpler to just bundle up two years' worth of all our personal information and send it directly to the Chinese.

Like the other national security legislation, the Government has failed to explain why we need this metadata storage legislation, with its provisions that far exceed anything permitted in places like the United States.

Government agencies already exploit the information they have about us in disturbing ways. In the year to June 2013, there were 319,874 authorisations to access telephone records, including 375 by Australia Post and 15 by Wyndham City Council in Victoria. Stored private data is a honey pot for intrusive snoops and bullies.

And the worst of it is, these immense data retention powers won't be used to fight terrorism - they're not really suited to that. Just as occurred in the UK, they will be used on minor welfare fraud, unpaid fines, and revealing journalists' sources.

Data retention legislation is wrong on fundamental grounds. Governments are supposed to serve the people, not treat them as presumptive criminals. We should be watching the Government, not the other way around.

David Leyonhjelm is Liberal Democrats' Senator for NSW. He is on Twitter at @DavidLeyonhjelm. View his full profile here.