This repository contains two apps:

1. Digitally sign a document
2. Check document digital signature

Version: 0.9
License: GNU GPLv3

This application is designed for signing contracts, agreements, and other documents with a digital signature in cases where this form of transaction is not prohibited.

1. create digital signature keys;
2. sign a file with a digital signature;
3. export a public key for a third party.

This application is designed for digital signatures verification, and documents integrity verification, signed with GPG and the application "Digitally sign a document".

1. check a digital signature;
2. import a public key from a signing person.

Current version tested on:
Windows 10 1909
macOS Big Sur (version 11, x86_64, on arm should work too)
Ubuntu 20.04 LTS (gpg version 2 package required)

Binary distributions for all operating systems mentioned above can be found in builds directory. Please, see the notes below, otherwise the apps will produce unpredictable errors.
Notes:

• On Windows install the apps into a path which contains only English characters.
• On macOS you need to allow installation from any sources (other than AppStore).
• On Linux if you have non-English locale it is necessary to remove (rename) gpg localization files in order to make gpg to use only English output messages (e.g. on Ubuntu 20.04: sudo mv /usr/share/locale-langpack/your_locale/LC_MESSAGES/gnupg2.mo /usr/share/locale-langpack/your_locale/LC_MESSAGES/gnupg2.mo.old with your_locale changed to your language locale). On Linux you unpack and run the apps from any folder.

Application utilizes to function GPG program: https://gnupg.org
It basically simplified graphical user interface for that program.
Source code written in PureBasic: https://www.purebasic.com

Linux:

macOS:

0.9 - translated to English.
0.8 - added: help, view the file to sign, other improvements.
0.7 - initial version, however, never released.