PlainTextMailSlayer
The PlainTextMailSlayer is a little application used to 'proxy' mails to encrypt them using OpenPGP. It allows you to send encrypted mails from application which do not support sending encrypted mails.
PlainTextMailSlayer was created to handle some edge cases and I am sharing the source in the case somebody needs it. Don't expect too much. However, I will accept pull requests if you want to improve it.
Installation
A simple
bundle install
should install all the dependencies. In addition, you have to create a
config.yml file. A template can be found in config.yml.example, the
keys should be self-explanatory.
One note: If you set encrypted_mails.subject_overwrite, all subjects from encrypted mails will get replaced by that to make sure no private data is exposed unencrypted. Leave it empty to use the original subjects.
Key and address management
You can manage your keys using the gpg cli interface. Make sure you import the keys with the same user that will run PlainTextMailSlayer or it won't be able to find the keys.
In addition, you have to add all recipients of encrypted mails to the config file. Addresses not listed in the config file will not get encrypted mails, regardless if there is a key available or not.
Usage
To start, run
foreman start
and the application will spawn an SMTP server listening at localhost:2525. Set up the applications sending unencrypted mails to send mails to localhost:2525. PlainTextMailSlayer will take care of all mails that are coming in, so make sure it is not accessible from outside, there is no authentication enabled.