Remove Signature From PDF File - Aspose Documentation

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Remove Signature from PDF File Contents [ Hide ]
  1. Remove Digital Signature from the PDF File
    1. Remove Signature but Keep the Signature field

Remove Digital Signature from the PDF File

When a signature has been added to a PDF files, it is possible to remove it. You can remove either a particular signature, or all signatures in a file. The fastest method for removing the signature also removes the signature field, but it is possible to just remove the signature, keeping the signature field so the file can be signed again.

The PdfFileSignature class RemoveSignature method allows you to remove a signature from a PDF file. This method takes the signature name as an input. Either specify the signature name directly, to remove all signatures, get the signature names using the GetSignNames method.

The following code snippet shows how to remove digital signature from the PDF file.

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET private static void RemoveSignature() { // The path to the documents directory var dataDir = RunExamples.GetDataDir_AsposePdf_SecuritySignatures(); using (var pdFileSignature = new Aspose.Pdf.Facades.PdfFileSignature()) { // Bind PDF document pdFileSignature.BindPdf(dataDir + "signed_rsa.pdf"); // Get list of signature names var sigNames = pdFileSignature.GetSignNames(); // Remove all the signatures from the PDF file for (int index = 0; index < sigNames.Count; index++) { Console.WriteLine($"Removed {sigNames[index]}"); pdFileSignature.RemoveSignature(sigNames[index]); } // Save PDF document pdFileSignature.Save(dataDir + "RemoveSignature_out.pdf"); } }

Remove Signature but Keep the Signature field

As shown above, the PdfFileSignature class RemoveSignature method lets you remove signature fields from PDF files. When using this method with versions prior to 9.3.0, both the signature and signature field are removed. Some develoeprs want to remove only the signature and keep the signature field so that it can be used to resign the document. To keep the signature field and only remove the signature, please use the following code snippet.

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET private static void RemoveSignatureButKeepField() { // The path to the documents directory var dataDir = RunExamples.GetDataDir_AsposePdf_SecuritySignatures(); using (var pdFileSignature = new Aspose.Pdf.Facades.PdfFileSignature()) { // Bind PDF document pdFileSignature.BindPdf(dataDir + "signed_rsa.pdf"); pdFileSignature.RemoveSignature("Signature1", false); // Save PDF document pdFileSignature.Save(dataDir + "RemoveSignature_out.pdf"); } }

The following example shows how to remove all signatures from fields.

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET private static void RemoveSignatureButKeepField2() { // The path to the documents directory var dataDir = RunExamples.GetDataDir_AsposePdf_SecuritySignatures(); using (var pdFileSignature = new Aspose.Pdf.Facades.PdfFileSignature()) { // Bind PDF document pdFileSignature.BindPdf(dataDir + "signed_rsa.pdf"); var sigNames = pdFileSignature.GetSignatureNames(); foreach (var sigName in sigNames) { pdFileSignature.RemoveSignature(sigName, false); } // Save PDF document pdFileSignature.Save(dataDir + "RemoveSignature_out.pdf"); } }

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