In the “Secure PDF Files With a Password in C#, VB, and Java” article, we described how to use the PDFFile class from the PDF SDK to password protect and encrypt PDF files. Using the PDFFile class also makes digitally signing PDF files just as easy! The PDFFile class is available for .NET FX, .NET Core, and Java.

Digital signatures are one of the most advanced and secure type of an electronic signature. These signatures provide the highest level assurance and are used to comply with legal and regulatory requirements. Digital signatures use a certificate-based digital ID to authenticate the signer's identity and bind each signature to the document using encryption. With the LEADTOOLS SDK, developers can use LEADTOOLS PDF libraries to retrieve information on these digital signatures. The .NET and Java PDFSignature Class contains properties of a PDF digital signature.