Brazil has confirmed plans to create a secure email service, following revelations of cyber-surveillance techniques used by the US and UK.President Dilma Rousseff posted a series of tweets over the weekend, saying the move was required to "prevent possible espionage". She added the country's Federal Data Processing Service (Serpro) would be charged with developing the system.
One expert said the tech involved was well established but had limitations.
"There's a good precedent for this with the German provider Gmx.de," said Prof Ross Anderson, head of the security research group at the University of Cambridge's computer laboratory.
"They just need to tell a company to keep the servers in Brazil, encrypt all the traffic inside or outside the country, and only give access to Brazilian police and intelligence services.
"Bang, finished, it's trivial. It's a well understood and well solved problem."
He said that the Brazilian system could be designed to interact with Gmx and equivalent encrypted services, in which case the NSA (US National Security Agency) and GCHQ (UK Government Communications Headquarters) would effectively be shut out unless the countries where the relevant servers were based decided to co-operate.