Internet giant Yahoo said in a blog post that all of the traffic to its data centres is now encrypted.
The company said it also planned to introduce additional security to other services, including Yahoo Messenger.
Last November, Yahoo chief executive Marissa Mayer announced the company's security measures in the wake of US surveillance disclosures.
Since then, users have already been able to access secure versions of popular products like Yahoo Sports.Continue reading the main story
Our goal is to encrypt our entire platform for all users at all time[s], by default”End QuoteAlex StamosYahoo
The move came after whistle-blower Edward Snowden leaked documents that alleged that the National Security Agency (NSA) used various technologies to spy on US citizens that included routinely asking firms like Yahoo and others for user information as well as tapping fibre-optic cables that carry global information networks.
Yahoo said that as of March 31, all information being transmitted from one Yahoo data centre to another is now encrypted, making it more difficult for outsiders to decipher emails and other information flowing between the centres.
Search requests made on Yahoo's home page are also now automatically encrypted, and Yahoo said it was planning to add additional security measures to Messenger and video chat in the coming months.
"Our goal is to encrypt our entire platform for all users at all time[s], by default," wrote newly installed chief security information officer Alex Stamos in the blog post.
"We will continue to work hard to deploy the best possible technology to combat attacks and surveillance that violate our users' privacy," he added, without specifically mentioning the US government surveillance or allegations that the NSA spied on Yahoo users.
Yahoo joined eight other companies, including Google, Facebook, and Apple, to call for reforms to US surveillance programmes in December.