Each industry has a company that comes to define it, and in their approach to business, they often reveal something about the era in which they operate. As textile companies once represented the modernity ushered in by the industrial revolution, and the Ford motor company reflected fossil-fuel supported urbanism, today’s era is influenced by the large Silicon Valley tech companies that mould our online experience, such as Google and Facebook.

When Google launched in the late 90s its motto was remarkable, and not only for its brevity. In three short words - “Don’t be evil” - the company set out not what it does or what it aims to be, but rather what it wants to avoid becoming. Facebook similarly espoused a positive philosophy of bringing the world together, connecting and empowering people in an equal digital space.

In recent years, the way these companies have handled data has come under increased scrutiny. The Cambridge Analytica scandal, in which Facebook users’ personal data was used to build individual psychological profiles that could be targeted by provocative political advertisements, have led many to question the cost of giving away data online, and the intent of the guardians of this information.

This is particularly relevant for European cities as the momentum towards establishing “smart cities” continues apace. How can cities ensure that data is used appropriately?

Jens Dambruch, Research fellow with Fraunhofer IGD and technical partner within the smarticipate project, believes that although opening up data provides excellent opportunities for cities, local governments should be mindful of the potential pitfalls: "The security aspects of open data are always to be considered. If you publish information on the location of gas pipes in the city streets, for example, this can lead to threats, in the sense that people looking to carry out terror attacks now know where the vulnerabilities are. You can abuse any kind of data if that's your intention, and that is always to be kept in mind, particularly when it's government data. There needs to be proper legislation in place to handle this."

Europe’s leading smart cities are outfitted with sensors that track a huge range of urban processes, from traffic congestion to noise levels to urban pollution. Taken together this information reveals trends, which allows the city authorities to react.

Increasingly, objects are being connected to the internet to transmit data back to a central unit – city bikes report their journey routes, urban bins provide data on the level of recycling carried out, traffic lights monitor the number of cars passing through a specific junction, and so on. Making objects data hubs – the so-called “Internet of Things” - is changing the way cities in Europe operate.

Jan Peters-Anders of the Austrian Institute of Technology encourages local governments to be cautious when looking to expand the amount of data collected: "Oftentimes 'open data' just means providing access to data that the city administration stores anyway. In terms of expanding the amount of data sets collected, this can lead to vulnerabilities: the more devices you have [connected to the Internet of Things] the higher the risk of being hacked.”

To safeguard themselves against these threats, cities are encouraged to train their staff on issues surrounding data privacy, even appointing an expert to oversee issues related to the management of data if possible.

Any private sector vendors that the city works with should be held to a strict agreement regarding data privacy, with well defined terms for what the data can – and cannot – be used for.

Before data is collected, the local government should decide what it is aiming to achieve, and from this starting point consider the minimum amount of data that must be collected to achieve this. If a city wishes to count how many bicycles cross a certain bridge, for example, is it necessary to capture faces of the cyclists, or can less intrusive means be used? Where possible, information collected should be anonymous and taken in bulk, making it difficult to track the habits of specific individuals.

The threats of data being misused may seem more present than ever before, but Jens Dambruch argues that this is not necessarily so. Dambruch acknowledges that present security measures intended to protect against hacking are often inadequate, but disputes that the dangers faced are necessarily the result of cities making the data they have access to open to the public.

"When cities and national governments talk about opening up data the media takes an interest, and you start to hear a lot of, sometimes scandalous, stories about hacking. The truth is that this [hacking] has been happening for a long time - when the data was held behind closed doors, we just didn't know about it!”

By collecting, using and treating data wisely, European cities can enjoy the benefits of being a smart city without compromising their – or their citizens’ – privacy.