Instant Messaging

Instant messaging (IM) is a technology that allows messages to be transmitted instantly. This article will focus on comparing features and privacy concerns between IM solutions.

IM Solutions

IM can be found in social media apps like Discord, Instagram, Whatsapp, Telegram and many others but its usually thru the use of a protocol. The most common protocol for IM is XMPP, though other options exist like IRC and WebRTC.

Privacy Concerns

On every IM solution there will always be metadata stored on the server about their users and messages, and some might not even have end-to-end encryption, which makes it harder to have a private conversation over the internet.

Software Comparison

Software	E2EE	Federated	License	Data Collected	Metadata
XMPP	Optional (OMEMO/PGP)	Yes	Depends on server/client	JID (Jabber ID) messages (can be encrypted) timestamps IP (depends on server) Message history (depends on server config)	JID Client name Presence
Matrix	Optional (MEGOLM)	Yes	Depends on server/client	Matrix user ID Email (depends on server) IP adress	timestamps IP addresses Presence Everyone present in the room
Signal	Yes (signal protocol)	No	AGPL-3.0 (server), GPL3 (client and protocol)	IP adress Phone Number	timestamp of last connection contacts (hashed) date of registration

References

XMPP:

• https://xmpp.org/extensions/xep-0313.html
• https://xmpp.org/extensions/xep-0446.html
• https://xmpp.org/extensions/xep-0084.html

Matrix:

• https://wire.com/en/blog/matrix-not-safe-eu-data-privacy
• https://hackea.org/notas/matrix.html
• https://forum.hackliberty.org/t/why-we-abandoned-matrix-the-dark-truth-about-user-security-and-safety/224
• https://gist.github.com/subpub/cbaa02ae2ec56ff19e63ea7126a78b7f

Signal:

• https://eprint.iacr.org/2016/1013.pdf