# encryption: encryption sessions handling

Libervia being an XMPP client does encryption by default between client and server. In addition, Libervia is also capable of doing end-to-end (e2e) encryption, meaning that the payload of messages are encrypted to be hidden from the servers (and their administrators). The `encryption` commands are here to handle those e2e encryption sessions and algorithms.

Note

For the moment, only one 2 one chat messages can be e2e encrypted

## algorithms

Display e2e encryption algorithms available in this instance of Libervia.

### example

Show available e2e algorithms:

    $ li encryption algorithms

## get

Display which encryption session is currently active with the given entity.

The only required argument is the JID of the entity.

If not e2e encryption session exist, a message will be displayed and li will exit with a non zero code: this means that the messages are in clear in the XMPP servers, but normal XMPP encryption is not affected (message should still be encrypted between client and server and between servers).

If an e2e encryption session exist, you’ll see the algorithm name and its namespace. In case of e2e encryption which only works from device to device (e.g. it’s the case with `OTR` which doesn’t support multiple devices), you’ll also see the resources of the devices where the encryption is active in `directed_devices`

### example

Check if session is encrypted with Louise:

    $ li encryption get louise@example.org

## start

Start e2e session with an entity.

You need to specify the JID of the entity you want to start a session with as a positional argument.

By default, Libervia will select itself the algorithm to use among those available, but you can specify one using either its name with `-n NAME, --name NAME` or its namespace using `-N NAMESPACE, --namespace`. `NAME` is the short name of the algorithm, e.g. `omemo` while the namespace is the longer (e.g. `urn:xmpp:otr:0`).

If an encryption session is started but one with an other algorithm was already there, the original session will be stopped and replaced by one with the new requested algorithm. You can change this behaviour by using `--encrypt-noreplace`: in this case the command will fail in case of conflict (e2e encryption is requested with a new algorithm while an e2e encryption session was already started with an other algorithm), and return a non-zero code. If an e2e encryption session was already started with the requested algorithm, the command will succeed in all cases and nothing will be changed.

### examples

Start e2e encryption with Pierre, using the algorithm selected by Libervia:

    $ li encryption start louise@example.net

Start an OMEMO session with Louise:

    $ li encryption start -n omemo louise@example.org

## stop

Terminate an e2e session with given entity. The entity must be specified as positional argument.

After this command is run, the messages with specified entity will not be e2e encrypted anymore (but this won’t affect encryption between Libervia and XMPP server and between XMPP servers).

### example

Stop the e2e encryption session with Pierre:

    $ li encryption stop pierre@example.net

## trust ui

Run the user interface to handle trust with given entity and given algorithm. The user interface depends on the algorithm used, but it generally shows you the fingerprints associated with your contact or contact devices, and asks you if you trust them or not.

The only mandatory argument is the jid of your contact.

By default the currently active encryption session algorithm is used, but you may manage trust for another algorithm by using `-n NAME, --name NAME` or `-N NAMESPACE, --namespace NAMESPACE`.

Note

Trusting a contact or a device means that you certify that this contact or device is the one you want to talk too. You should not trust a device if you have not verified by an external channel (i.e. not XMPP) the fingerprint. The best way is to verify the fingerprint physically if possible (i.e. in front of your contact, not with computer networks in the middle).

### example

Manage `OMEMO` trust with Louise devices:

    $ li encryption trust ui -n omemo louise@example.org