Facebook is reportedly considering a merger of its three messaging platforms – WhatsApp, Instagram and Facebook Messenger – allowing users to send messages between the networks for the first time.

The plans are said to come directly from the Facebook chief executive, Mark Zuckerberg, the New York Times has reported, and would involve rewriting the basic software of the three apps to ensure they were interoperable. A WhatsApp user would be able to, for instance, text an Instagram user for the first time without needing to switch applications.

That rewrite would also involve enabling end-to-end encryption (E2E) on all three apps, according to the NYT’s Mike Isaac. While all WhatsApp messages use that security feature, which prevents anyone, including Facebook itself, from intercepting the contents of messages, support across Facebook’s wider business is patchy. Facebook Messenger only supports E2E in a special “secure conversations” mode, which is off by default and must be enabled separately for every chat, while Instagram features no encryption at all.

While E2E is a valuable security measure for users, it has the side effect of preventing Facebook from scanning messages as part of its advertising business. The technology has also come under attack from law enforcement organisations, since it hinders their ability to intercept suspect communications in real time.

Mark Zuckerberg, the Facebook CEO, is reported to have come up with the idea to merge the messaging platforms. Photograph: Marcio José Sánchez/AP

In a statement, Facebook told the Guardian: “We want to build the best messaging experiences we can; and people want messaging to be fast, simple, reliable and private.

“We’re working on making more of our messaging products end-to-end encrypted and considering ways to make it easier to reach friends and family across networks. As you would expect, there is a lot of discussion and debate as we begin the long process of figuring out all the details of how this will work.”

The news has raised concerns among both privacy researchers and antitrust experts.

Matthew Green, a cryptography professor at Johns Hopkins University, said the change “could be potentially be good or bad for security/privacy”.

He added: “But given recent history and financial motivations of Facebook, I wouldn’t bet my lunch money on ‘good’. Now is a great time to start moving important conversations off those services.”

In a thread on Twitter, Green wrote that his two major concerns were that the widespread rollout of E2E could result in WhatsApp getting comparatively less secure, rather than Facebook Messenger and Instagram becoming as secure as possible; and that WhatsApp users, who currently do not need to share much personal information at all with Facebook, may find their metadata co-mingled with their broader Facebook accounts.

Jan Koum, co-founder of WhatsApp, left his job as CEO of the messaging app in April. Photograph: Mike Blake/Reuters

For similar reasons, the attempts to merge the networks could hit a stumbling block in Europe, where Facebook has once before been prevented from transferring data from WhatsApp to Facebook’s main service. In November 2016, the company was forced to halt a transfer of data following complaints from the pan-European data protection agency. The company was also forced by the UK’s information commissioner to promise not to do any transfers of EU user data until after the general data protection regulation (GDPR) came into force on 25 May 2018.

Antitrust experts have noted that the merger of the three apps could make it harder to force Facebook to spin off WhatsApp or Instagram in the future, if a competition commissioner decided to force a demerger for anti-monopoly reasons.

The founders of both WhatsApp and Instagram left Facebook in mysterious circumstances in 2018. Brian Acton, the co-founder of WhatsApp, left in 2017 but went one step further in March, joining calls to “#deletefacebook” in a post on Twitter. Acton’s co-founder, and WhatsApp’s chief executive, Jan Koum, quit in April, announcing that he was “taking some time off to do things I enjoy outside of technology, such as collecting rare air-cooled Porsches, working on my cars and playing ultimate Frisbee”.

Then, in September, Instagram’s co-founders both quit at the same time without giving a reason other than saying they were departing to explore their “curiosity and creativity again”.