Instant messaging services have become the main communication method for many people, but a lack of interoperability means users often need to install several messengers and learn different operating concepts to communicate with all their contacts. However, the EU’s Digital Market Act (DMA) has put pressure on dominant messenger providers, such as Apple and Facebook, to offer text messaging capabilities with smaller messengers by next year. To enable interoperability, the Internet Engineering Task Force has formed the More Instant Messaging Interoperability (MIMI) working group to develop open specifications for all messenger operators to use.
One protocol that has been proposed for interoperability is Matrix, developed by a foundation that has been creating it as a federated system and an alternative to centrally established messenger services since 2014. However, the protocol has vulnerabilities that need to be addressed. Other challenges include determining user IDs and protecting confidentiality and anonymity. Some messenger operators, such as Threema, have concerns about interoperability, citing potential economic and security issues.
The complexity of creating an interoperable system that ensures security and usability has been a challenge for researchers. According to Ross Anderson and Jenny Blessing from the Universities of Edinburgh and Cambridge, respectively, cryptographic protocols need to be supported by new processes, protocols, and features to maintain security and usability. The complexity of the interoperable system could compromise security by increasing the number of dynamic parts that need protection.
As the deadline for interoperability approaches, the MIMI working group needs to agree on a specification, including the Matrix protocol, MLS for end-to-end encryption, SPIN for inviting numbers, and delivery solutions between messengers. The IETF could rely on its specifications, but interoperability remains a Herculean task with an uncertain outcome.
