New York (CNN Business) WhatsApp has amassed two billion users, up from 1.5 billion by the end of 2017, the company announced on Wednesday.

Facebook FB The mobile messaging app was founded in 2009 and acquired byin 2014. The deal was valued at $19 billion, the largest acquisition by the social media giant to date.

Despite its size, WhatsApp's growth remains robust: It has gained 500 million new customers over the past two years.

WhatsApp touts its end-to-end encryption technology , which ensures that all contents in chats are secured by default. Not even WhatsApp can read messages or listen to calls that take place among the participants of conversations, according to WhatsApp's blog posts.

But the encryption technology has drawn backlash across the world for security reasons. In India, where WhatsApp has more users than any domestic messaging apps, the government has called for regulations that give it access to encrypted data. In Australia and the United Kingdom, similar laws are also in discussion.

Read More