Here is an explainer on the rights and obligations entailed under the General Data Protection Regulation (GDPR), which launched on May 25, 2018.

- Power to the people -

These are the main rights guaranteed to European internet users under the GDPR.

1. The right to be informed. Internet users who hand over personal data have the right to know how it will be used, how long it will be kept and whether it might be used outside the European Union.

2. The right to access, correct and erase data. Users are able to transfer their data to another service provider, or receive it themselves in a usable format.

3. The right to be forgotten. Users can ask that they no longer appear in searches, although this right is also balanced against the public's right to know.

4. The right to challenge algorithms. If algorithms play an important role in decisions, such as admission to universities, those affected have the right to challenge the decision and request human intervention.

5. The right to contest violations of rights. Each country's information rights agency accepts complaints. If the complaint concerns a company in another EU state, it is be transferred to the regulator in that country. Final decisions taken by all the national agencies together are binding across the EU.

- Rules for companies -

For companies, the regulations are not one-size-fits-all. Their obligations depend on what kind of data they collect, what they do with it and their size. It doesn't matter if they are European firms or not -- if they collect data from Europeans then the GDPR applies to them.

For most small and medium-sized businesses the regulations simply protect the information they have on their clients and suppliers using the "rules of common sense", in the words of France's data protection agency CNIL.

One of the GDPR's main objectives is to reduce the amount of data being collected and processed from the start.

This means that firms should evaluate what data they really need, and then how to protect it. The information should then be updated regularly.

Clients and subcontractors should also be informed about what data is being collected and what for, as well as how they can exercise their rights.

Companies also need to set out policies on who has access to data and how, designate who is responsible for data protection, and put into place all necessary measures to safeguard the data, particularly sensitive information.

Firms also have the right to appeal to their national data regulator.