President Dilma Rousseff signed into Brazilian law on Wednesday a “bill of rights” for the digital age.

It aims to protect online privacy and promote the internet as a public utility.

The new law bars telecoms companies from charging for preferential access to their networks and limits the data that online companies can collect on internet users, deeming communications over the internet “inviolable and secret.”

The law was signed by President Rousseff at a global conference on the future of internet governance and puts Brazil in the vanguard of online consumer protection and what is known as “net neutrality,” whose promoters consider it profoundly democratic.

Service providers must develop protocols to ensure email can be read only by senders and their intended recipients.

Violators are subject to penalties including fines and suspension.

The law obliges internet companies, however, to hold on to user data for six months and hand it over to law enforcement under court order.

The law won final approval in the Senate late on Tuesday and coincided with the conference, which is an effort to chart a path to a less US-centred internet.

Brazil cast itself as a defender of internet freedom after revelations last year that the US National Security Agency had spied on President Rousseff, her close advisers and Brazilian commercial interests, including the state-run oil company Petrobras.

Attendees at the 800-strong NETMundial forum yesterday praised Ms Rousseff’s initiative.

“It is a fantastic example of how governments can play a positive role in advancing web rights and keeping the web open,” said World Wide Web inventor Tim Berners-Lee.

President Rousseff called the law’s “net neutrality” clause “fundamental to maintaining the internet’s free and open nature.”

It bars companies that sell internet services from turning their networks into toll roads.

Such companies argue they need to charge more for content that demands higher bandwidth, such as video streaming or voice communications.

But net neutrality advocates say the internet should be treated as a public utility, especially as consolidation in the telecoms business reduces the number of providers so that many operate as near monopolies.