# Messaging Client The messaging client is a [BSP client](https://code.briarproject.org/briar/briar-spec/blob/master/protocols/BSP.md) that synchronises private messages between pairs of devices. ### Identifier The client's identifier is `org.briarproject.briar.messaging`. The major version is 0. ### Groups The client uses a separate BSP group for communicating with each contact. The [group descriptor](https://code.briarproject.org/briar/briar-spec/blob/master/protocols/BSP.md#23-groups) is a [BDF list](https://code.briarproject.org/briar/briar-spec/blob/master/BDF.md) containing the unique IDs of the contacts' identities, sorted in ascending order as byte strings. ### Message types **PRIVATE_MESSAGE** - The message body is a BDF list with one element: `text` (string). ### Validity policy * A private message is valid if it is well-formed. ### Storage policy * All messages are stored. ### Sharing policy * All local messages are shared.