Twitter said it has implemented a security technology that makes it harder to spy on its users and called on other Internet firms to do the same, as Web providers look to thwart spying by government intelligence agencies.

Twitter, which began communications in 2011 using traditional HTTPS encryption, said it has added an advanced layer of protection for HTTPS known as "forward secrecy".

"Since a year and a half, it has become clearer and clearer how important that step was to protecting our users' privacy", Twitter said.