PortableSigner is described as 'Signing (with X.509 certificates) program for PDF files. It's platform independent and runs (tested) under Windows (2000, XP, ...), Linux, and macOS' and is an app in the office & productivity category. There are more than 25 alternatives to PortableSigner for a variety of platforms, including Windows, Mac, Web-based, Android and iPhone apps. The best PortableSigner alternative is Adobe Acrobat DC. It's not free, so if you're looking for a free alternative, you could try PDFTK Builder or KDAN PDF. Other great apps like PortableSigner are Qoppa PDF Studio, Nitro PDF , LibreSign and DottedSign.
JSignPdf is a Java application which adds digital signatures to PDF documents. It can be used as a standalone application or as an Add-On in OpenOffice.org. The application uses the jsignpdf-itxt library for PDF manipulations (based on iText library in version 2.1.
PDFTools is a PDF management application. It can encrypt, decrypt, join, split, stamp, create and rearrange a PDF file.
Electronic Signature Service for Your Business. Sign and send documents for signing online.
Free Digital Signature Software that works without any file upload to ensure privacy and security
Combine, merge and reorganize pages of multiple PDF pages and images into one PDF document without any file upload.
Advanced PDF Utilities Free comes in handy when you need to deal with PDF files such as to merge or split pages, convert PDF to text & convert image to PDF or vice versa. This multipurpose program comes with its nice, clean user interface covering most functions.
VeryPDF PDF Editor is an easy-to-use application designed for users familiar with Microsoft Office and similar applications. VeryPDF PDF Editor provides tools to enable you freely write your own comments to the PDF document and share the comments with others.
PDF Toolbox gives you the easiest way of editing PDF files without the need for expensive Adobe Acrobat software - saving you tons of money. PDF Toolbox integrates seamlessly with Click to Concert to provide a powerful PDF conversion and editing tool for your everyday needs.
OpenSignature is an open source project for the digital signature of documents. It works with all cards supported by OpenSC and focuses on adding support for cards from accredited Italian CAs.
The easy-to-use all-in-one PDF software that gives you the power to Read, Create, Edit, Secure, Convert and Print PDF files.
XolidoSign, the best technology for electronic signature, time stamping and verification of all types of intelligent documents (PDF integrated firm, images, etc..).
GoSigner is an intuitive and easy free electronic signature app that allows users to send eSign Documents, Sign PDF documents online.
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