Is There a Free Open Source Digital Signature Software to Sign Documents?

Yes, there are several free and open-source digital signature software options that can stamp a signature onto a document and save it, similar to how Adobe or DocuSign operates. The following will explore some notable options to consider when integrating digital signatures into your software application or business process.

LibreOffice - A Powerful Office Suite with Digital Signature Capabilities

Description: LibreOffice is a comprehensive office suite that includes tools such as a word processor, spreadsheet, and more. It supports digital signatures for documents, making it a versatile option for businesses that need to sign documents electronically.

Features: Within the application, you can create and apply digital signatures to documents in formats like .odt and .pdf. Additionally, you can automate LibreOffice via command line or macros to fit your business process.

Integration: Automating LibreOffice would require some scripting knowledge or the use of a scripting language like Python for better integration. However, it can be adapted to fit your needs if you have the necessary development resources.

OpenSSL - A Robust Toolkit for Digital Signatures

Description: OpenSSL is known for its robust toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. However, it also allows for the creation and verification of digital signatures. It is a command-line tool, making it less user-friendly but highly customizable and secure.

Features: OpenSSL allows you to create digital signatures for files, though it requires some command-line knowledge. This makes it a suitable option for backend integration into applications where you manage the signing process programmatically.

Integration: It is ideal for backend applications where command-line tools can be invoked. By incorporating OpenSSL into your application, you can handle digital signatures in a secure and efficient manner.

DigiSigner - A Free PDF Signing Tool

Description: DigiSigner is a free PDF signing tool that allows you to sign PDF documents digitally. While not open-source, it offers a free tier and can be integrated into workflows, making it an appealing choice for businesses.

Features: DigiSigner supports both digital signatures and visible signature stamps. This can be particularly useful for businesses that need to maintain a high level of transparency and visibility.

Integration: DigiSigner can be integrated into existing workflows and processes with ease, allowing for a user-friendly experience. It is more straightforward compared to command-line tools but still requires some setup and configuration.

GnuPG GPG - A Free Implementation of OpenPGP Standard

Description: GnuPG is a free implementation of the OpenPGP standard. It allows you to encrypt and sign your documents. While it may require additional steps to integrate with document formats, GnuPG is an excellent choice for businesses that prioritize security.

Features: You can use GnuPG to create digital signatures for files, although it may require some additional steps to integrate with document formats. It is a powerful tool, but you may need to spend more time setting up the integration.

Integration: It can be integrated into applications for automated signing processes, making it suitable for businesses that require a secure and automated digital signature solution.

pdfsig - A Command-Line Tool for Signing PDF Files

Description: pdfsig is a command-line tool that uses OpenSSL to apply digital signatures to PDF files. It is straightforward to use and highly customizable.

Features: This tool allows you to apply digital signatures to PDF files, making it a suitable choice for backend integration into applications where command-line tools can be invoked.

Integration: It is ideal for developers who prefer command-line solutions. With pdfsig, you can easily sign documents programmatically without the need for a graphical user interface.

SignServer - An Open-Source Server-Based Solution

Description: SignServer is an open-source server-based solution for signing documents with various formats. It supports PDF, XML, and other formats with flexible signing options.

Features: SignServer is specifically designed for integration into web applications and business processes, making it a comprehensive solution for businesses that require a robust digital signature solution.

Integration: It is suitable for both backend and frontend applications, allowing for seamless integration into your existing workflow.

Considerations for Integration

API Availability: Check if the software offers APIs or command-line interfaces for easier integration into your application. Document Format Support: Ensure the software supports the document formats you are working with, such as PDF, DOCX, and others. User Experience: Consider how the signing process will be presented to users and whether it aligns with your business process.

Conclusion

Each of these tools has its strengths and weaknesses depending on your specific needs for integration, document types, and the user experience you want to provide. If you are looking for a solution that can be easily integrated into a larger application, consider using OpenSSL or GnuPG for backend processes. Alternatively, explore options like LibreOffice or DigiSigner for a more user-friendly interface.