Disappearing Messages v2: a new way to protect your privacy with Session. 

Disappearing messages are a basic but essential feature for private digital communication.

The reason why encryption is absolutely crucial when you talk to people online is that unlike speaking to someone in person, online communication creates a record of everything that you’re saying. Anyone would feel uneasy about having their speech recorded and viewable in a stranger’s database, especially when they’re having personal conversations.

When you use Session, your conversations are end-to-end encrypted and only able to be viewed by you and the people that you’re speaking to. For added protection, we use anonymity-by-default and decentralisation to make sure that whoever is operating the server that routes your messages has no idea whose encrypted messages they are passing on to the recipient.

Disappearing messages can take your privacy even further by ensuring that when you share highly sensitive information, it can be removed from your conversation entirely after a period of time you’re comfortable with. Our newest update will totally overhaul the way disappearing messages work in Session to make it more intuitive and introduce additional functionality that wasn’t previously available.

Building an application on a decentralised network can make simple things become complex. Disappearing messages might seem like a simple feature, but without a centralised ‘source of truth’ who keeps track of how and when messages should disappear, things become a lot harder. But…building Session has never been simple – and we always embrace the challenges.

Previously, all messages on the Session Network had a default 14 day TTL (time-to-live), meaning that messages remain in your swarm (the group of servers that store your messages) for two weeks, after which time they exist only in local storage on your device. When you delete a message manually, it is removed from the network, but the 14 day TTL previously applied to all messages, including those which had disappeared from your device.

Our new approach to disappearing messages means that when you choose for a message to disappear at a certain time, it will be removed from any device involved in your conversation as well as the network itself. The update will also introduce new ways to decide when the message should disappear, and allow each participant in a conversation to set their own unique settings. 

Flexible TTL

When you choose for your message to Disappear After Read, it is sent to the recipient with a secret instruction to automatically change the message’s TTL to align with the time of expiration that you have selected. So if you select for the message to be deleted one hour after it’s been read by the recipient, it will be removed from your device, and your swarm 1 hour later. The recipient can then open that message any time before the end of its default 14 day TTL, at which point the message will be removed from their device and their swarm one hour later.

Disappear After Read

One-to-one conversations will now have the option for messages to ‘Disappear After Read’, as well as the existing ‘Disappear After Send’ option. This new feature is self-explanatory: you now have the option to choose for a message to disappear from your conversation at a set time after it has been read by the recipient, as well as the option for it to disappear at a set time after you’ve sent it. Groups will remain limited to ‘Disappear After Send’, because there are multiple participants who will read messages at different times. 

Per-user Settings

Because one-to-one conversations require two swarms to interact, there was previously no shared ‘source of truth’ for the disappearing messages setting in that conversation. To overcome this, we re-configured how the feature works to allow both participants to have their own settings — you might select for your messages to disappear 5 minutes after it's been read, and I might select one hour. This gives you more flexibility and also allows each swarm to have an independent source of truth on which to base your disappearing message settings.

So there you have it! A super-charged new disappearing messages system, custom made for decentralised messaging. We’ve been hard at work on another major release as well, which will provide the same kind of upgrade to Groups. We’ll be sharing some more about that release soon, so keep your eyes peeled 👀