Decentralized messaging and synchronization.

Library and simple CLI interface implementing the Erebos identity management, decentralized messaging and synchronization protocol, along with local storage. . Erebos identity is based on locally stored cryptographic keys, all communication is end-to-end encrypted. Multiple devices can be attached to the same identity, after which they function interchangeably, without any one being in any way "primary"; messages and other state data are then synchronized automatically whenever the devices are able to connect with one another. . See README for usage of the CLI tool.

Erebos

The erebos binary provides simple CLI interface to the decentralized Erebos messaging service. Local identity is created on the first run. Protocol and services specification is being written at:

https://erebosprotocol.net/spec

Erebos identity is based on locally stored cryptographic keys, all communication is end-to-end encrypted. Multiple devices can be attached to the same identity, after which they function interchangeably, without any one being in any way "primary"; messages and other state data are then synchronized automatically whenever the devices are able to connect with one another.

Status

This is experimental implementation of yet unfinished specification, so changes, especially in the library API, are expected. Storage format and network protocol should generally remain backward compatible, with their respective versions to be increased in case of incompatible changes, to allow for interoperability even in that case.

Usage

On the first run, local identity will be created for this device based on interactive prompts for:

Name: name of the user/owner, which will be shared among all devices belonging to the same user; keep empty when initializing device that is going to be attached to already existing identity on other device.

Device: name describing current device, can be empty.

After the initial setup, the erebos tool presents interactive prompt for messages and commands. All commands start with the slash (/) character, followed by command name and parameters (if any) separated by spaces. When a conversation is selected, message to send there is entered directly on the command prompt.

The session can be terminated either by end-of-input (typically Ctrl-d) or using the /quit command.

Example

Start erebos CLI and create new identity:

Name: Some Name
Device: First device
Some Name / First device
> 

Add public peer:

> /peer-add-public
[1] PEER NEW <unnamed> [37.221.243.57 29665]
[1] PEER UPD discovery1.erebosprotocol.net [37.221.243.57 29665]

Select the peer and send it a message, the public server just responds with automatic echo message:

> /1
discovery1.erebosprotocol.net> hello
[18:55] Some Name: hello
[18:55] discovery1.erebosprotocol.net: Echo: hello

List chatrooms known to the peers:

> /chatrooms
[1] Test chatroom
[2] Second test chatroom

Enter a chatroom and send a message there:

> /1
Test chatroom> Hi
Test chatroom [19:03] Some Name: Hi

Messaging

/peers
: List peers with direct network connection. Peers are discovered automatically on local network or can be manually added.

/contacts
: List known contacts (see below).

/conversations
: List started conversations with contacts or other peers.

/<number>
: Select conversation, contact or peer <number> based on the last /conversations, /contacts or /peers output list.

<message>
: Send <message> to selected conversation.

/history
: Show message history of the selected conversation.

/details
: Show information about the selected conversations, contact or peer.

Chatrooms

Currently only public unmoderated chatrooms are supported, which means that any network peer is allowed to read and post to the chatroom. Individual messages are signed, so message author can not be forged.

/chatrooms
: List known chatrooms.

/chatroom-create-public [<name>]
: Create public unmoderated chatroom. Room name can be passed as command argument or entered interactively.

/members
: List members of the chatroom – usesers who sent any message or joined via the join command.

/join
: Join chatroom without sending text message.

/leave
: Leave the chatroom. User will no longer be listed as a member and erebos tool will no longer collect message of this chatroom.

Add contacts

To ensure the identity of the contact and prevent man-in-the-middle attack, generated verification code needs to be confirmed on both devices to add contacts to contact list (similar to bluetooth device pairing). Before adding new contact, list peers using /peers command and select one with /<number>.

/contacts
: List already added contacts.

/contact-add
: Add selected peer as contact. Six-digit verification code will be computed based on peer keys, which will be displayed on both devices and needs to be checked that both numbers are same. After that it needs to be confirmed using /contact-accept to finish the process.

/contact-accept
: Confirm that displayed verification codes are same on both devices and add the selected peer as contact. The side, which did not initiate the contact adding process, needs to select the corresponding peer with /<number> command first.

/contact-reject
: Reject contact request or verification code of selected peer.

Attach other devices

Multiple devices can be attached to single identity to be used by the same user. After the attachment process completes the roles of the devices are equivalent, both can send and receive messages independently and those messages, along with any other sate data, are synchronized automatically whenever the devices can connect to each other.

The attachment process and underlying protocol is very similar to the contact adding described above, so also generates verification code based on peer keys that needs to be checked and confirmed on both devices to avoid potential man-in-the-middle attack.

Before attaching device, list peers using /peers command and select the target device with /<number>.

/attach
: Attach current device to the selected peer. After the process completes the owner of the selected peer will become owner of this device as well. Six-digit verification code will be displayed on both devices and the user needs to check that both are the same before confirmation using the /attach-accept command.

/attach-accept
: Confirm that displayed verification codes are same on both devices and complete the attachment process (or wait for the confirmation on the peer device). The side, which did not initiate the attachment process, needs to select the corresponding peer with /<number> command first.

/attach-reject
: Reject device attachment request or verification code of selected peer.

Other

/peer-add <host> [<port>]
: Manually add network peer with given hostname or IP address.

/peer-add-public
: Add known public network peer(s).

/peer-drop
: Drop the currently selected peer. Afterwards, the connection can be re-established by either side.

/update-identity
: Interactively update current identity information

/quit
: Quit the erebos tool.

Storage

Data are by default stored within .erebos subdirectory of the current working directory. This can be overriden by EREBOS_DIR environment variable.

Private keys are currently stored in plaintext under the keys subdirectory of the erebos directory.