The repository is missing link to run Bitmessage as a docker container and provide IMAP and SMTP access for communications.

It is based on Notbit which is a minimal client for the bitmessage network.

That way the bitmessage can be used with any compliant mail program such as Thunderbird or Apple Mail.

The docker image is compact (~20MB) alpine-based, can run on Linux / Mac / Windows with the appropriate setup of Mail client supporting IMAP and SMTP

I am not a cryptography expert and I don't know whether Notbit or the Bitmessage protocol is actually safe for secure communications. I wouldn't recommend using for anything highly sensitive.

There is a choice of Intel or Arm architecture. The Arm version is built and tested on Raspberry Pi system and tested on Mac M1.

PC: linux/amd64:

docker pull yshurik/bitmessage:latest_x86

Raspberry Pi, Mac M1: linux/arm:

docker pull yshurik/bitmessage:latest_arm

First you may want to have dedicated docker volume for bitmessage data (keys etc):

docker volume create bm-data

Then the docker container can be started with appropriate port mappings for IMAP (143) and SMTP(25).

docker run -v bm-data:/data -d --name bm \
  -p 8444:8444 \
  -p 127.0.0.1:25:2525 \
  -p 127.0.0.1:143:143 \
  yshurik/bitmessage:latest

Note that on Mac it can be tricky way to access the volume files directly, so you may prefer to map an exisitng folder:

docker run -v /Users/anonymous/bm-data:/data -d --name bm \
  -p 8444:8444 \
  -p 127.0.0.1:25:2525 \
  -p 127.0.0.1:143:143 \
  yshurik/bitmessage:latest

From example above you can setup the Thunderbird to use IMAP from localhost, port 143, user: bm, password: bm. For sending use SMTP localhost port 25 (no auth and credential)

Not that in example above port 25,143 are mapped to 127.0.0.1 only so IMAP and SMTP can be accessed only from local machine.

Port 8444 (bitmessage) is mapped to all interfaces to make network connectivity with other peers.

On first run (so no keys.dat file <docker volume>/notbit/keys.dat) the initialization script will create your first personal address and send welcome email from yourself so you identify your From address for further use in emails as sender - appropriate key will be used from keys.dat.

If you already have some addresses from the official PyBitmessage client you can import these directly by copying over the keys.dat. file. To do this, make sure the container is stopped then type:

docker stop bm
cp ~/.config/PyBitmessage/keys.dat <docker volume location>/notbit/keys.dat
chown 1000.1000 <docker volume location>/notbit/keys.dat
docker start bm

The addresses used can not be real email addresses but instead they must be of the form <bitmessage-address>@bitmessage.

Note that any messages you send must have the content type set to text/plain and can't contain any attachments. This means that HTML messages won't work. They must use either the us-ascii encoding or UTF-8.