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](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 peer or contact is selected, message to send him can be entered directly on the command prompt.

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).

/<number>
Select contact or peer <number> based on previous /contacts or /peers output list.

<message>
Send <message> to selected contact.

/history
Show message history for selected contact or peer.

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.

/update-identity
Interactively update current identity information

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.