[REVIEW] : Sending a message from Whatsapp to iMessage: the interoperability puzzle

One of the consequences of this new regulation will be cross-platform operability. Eventually, Whatsapp or Messenger users could therefore send a message directly to a Signal user or any other messaging application.

Regulate the competition

The new European regulation on digital markets insists on interoperability, in particular, for questions of free competition. With over 4 billion users, Facebook currently acts as a “gatekeeper” to the digital messaging market. The impossibility of communicating from the smallest platforms to the large ones indeed forces users to switch to the giant messengers such as Whatsapp or Messenger.

The new European rules therefore stipulate that interoperability must be implemented at the request of the platforms. The law will obviously not be functional immediately, and the technical details are still not made public. It is known, however, that a company will be required to allow cross-platform messages to be sent three months after the request; the permeability of calls may take up to four years.

Risks for encrypted data

The major problem that arises is that of the encryption of the data contained in the messages exchanged. The main advantage of platforms like Whatsapp over SMS is the guarantee of confidentiality thanks to end-to-end encryption. If the applications start operating with each other, this encryption could be compromised.

Today, each instant messaging application uses a different encryption code. Thus, message encryption could be lost in transit from one platform to another. To avoid the problem, two solutions exist: the use of a bridge between the two platforms or the adoption of a universal encryption code.

However, the bridge would decrypt the message before transferring it, posing major confidentiality problems. The adoption of universal encryption would perhaps be more realistic, especially since protocols of this type, such as the “Matrix” protocol, already exist.

DMA and the Messaging Interoperability Puzzle

The Digital Market Act plans to oblige the main messaging platforms to interoperate. Many experts and security professionals see it as an insurmountable gas factory. The co-founders of Matrix, a protocol specifically promoting interoperability, see it as a godsend for the future of messaging.

“EU lawmakers have agreed that the biggest messaging services (such as WhatsApp, Facebook Messenger or iMessage) will have to open up and be interoperable with the smaller messaging platforms, if they so request,” read -on in the negotiations around the Digital Market Act, which the negotiators of the European Parliament and the Council validated last week:

“Users on small or large platforms will then be able to exchange messages, send files or make video calls on all messaging applications, which will give them a wider choice. »

Only companies “whose market capitalization reaches at least 75 billion euros or whose annual turnover exceeds 7.5 billion euros” will be affected.

If Signal and Telegram will therefore a priori be spared, such interoperability is not without problems: how to do, for example, to make end-to-end encrypted messaging (E2EE) such as WhatsApp interoperable with those that are not as an option, like Facebook Messenger?

Andreas Schwab, European Parliament rapporteur on the file, “it will come, but it will also have to be secure. If telecom regulators say it’s not possible to offer end-to-end encrypted group chats in the next nine months, we’ll do it as soon as possible, that’s for sure. »

According to him, messaging services subject to the interoperability requirement will have to open their APIs to competitors in order to provide interoperable messaging for basic functionality. Since the requirement is intentionally asymmetrical, this means that smaller messaging services that fall outside the DMA are not required to open to gatekeepers:

“The first basic messaging features will be user-to-user messages, video and voice calls, and basic file transfer (photos, videos), then over time other features such as group discussions will come. Everything must be end-to-end encrypted. »