Kate GPG Plugin

This plugin allows to GPG decrypt and encrypt text files using the GPGMe library in KDE's text editor KATE.

Features

Plugin shows all available GPG keys with basic name filtering (auto-selects the most recently created key)
Manual selection of key used for encryption
Symmetric encryption possible

Prerequisites

A CMake & C++ build environment is installed
Qt development libraries are installed
C/C++ bindings for GPGMEpp are installed
At least one public+private GPG key pair (if you only want to encrypt to yourself)

Caution!

While this plugin makes it easy to decrypt+encrypt text, it also makes it easy to mess things up. You could accidentally encrypt a file, e.g. with a key that is not yours, which then you wouldn't be able to decrypt. Or you could accidentally save a currently decrypted file as plain text, leaving it unecrypted.

Use with care!
Think twice before pressing Ctrl+S!
Ctrl+Z works after encryption and saving.

Build Instructions

Dependencies

This plugin was developed and built on Manjaro Linux running KDE Plasma. I have tested the build in a fresh non-KDE Ubuntu 22.04.3 LTS VM and had to install at least these packages manually:

git
cmake
extra-cmake-modules
cmake-extras
g++
kate
libgpgmepp-dev (this should also install qmake and quite a few Qt dev libs)
libgcrypt20-dev
libgpg-error-dev
libecm1-dev

This line should do it for recent Ubuntu based distributions:
sudo apt install git cmake extra-cmake-modules cmake-extras g++ kate libgpgmepp-dev libgcrypt20-dev libgpg-error-dev libecm1-dev

Build

Clone the git repository
Run CMake in the cloned folder:

This works for me with both Qt >= 5.15.* and Qt6.
cmake -B build/ -D CMAKE_BUILD_TYPE=Release -D QT_MAJOR_VERSION=5 (or 6)

cmake --build build/

Install the plugin to the Kate plugin path. This requires sudo!
- Recommended:
  sudo cmake --install build/
  (I had cases when this was unreliable... If this does not work see manual installation below)
- Manual installation in Manjaro:
  sudo cp build/kate_gpg_plugin.so /usr/lib/qt/plugins/ktexteditor/
  or if you prefer a symlink:
  sudo ln -s build/kate_gpg_plugin.so /usr/lib/qt/plugins/ktexteditor/
- Manual installation in Ubuntu:
  sudo cp build/kate_gpg_plugin.so /usr/lib/x86_64-linux-gnu/qt5/plugins/ktexteditor/
  (In my Ubuntu VM symlinking the plugin did not work. Plugin doesn't show up in Kate unless copied...)
Run kate (from the current terminal prompt)
Enable the "GPG Plugin" in Kate → Settings → Configure Kate → Plugins.
A new vertical button should appear in the left sidebar.

Limitations

Currently only the default email address for a key fingerprint will be used for encryption
No support for subkeys yet
Password prompts are handled by GPG(Me) and may look ugly. Won't touch this!

TODO

Automatically retrieve key fingerprint/ID and mail address from encrypted file to set as selected "To:" key and mail address
Attach to KATE's "Open File" dialog to suggest automatic decryption when a .gpg/.pgp/.asc file is opened

Attach to KATE's Save/Save As dialog to strongly suggest to re-encrypt a currently opened GPG file (to avoid saving it as unencrypted).
Sign and verify documents
Add support for subkeys

dennis2society/kate-gpg-plugin