Retrieving signature information from a signed PDF

This java sample program shows how to open a signed PDF and retrieve signature information from it such as signer’s name, sign reason, location, date, etc…. This sample uses Qoppa’s Java PDF Library jPDFSecure but can be easily changed to use jPDFProcess. // Load the signed document PDFSecure pdfDoc = new PDFSecure ("C:\\test\\output.pdf", null); if(pdfDoc.getSignatureFields() […]

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Signing a PDF with a p12 file in Java

This is a sample java program showing how to sign a PDF document using a certificate loaded from a p12 file. The signature appearance is customized with an image, signer’s name and date. A signature field is added to the PDF document and then signed. This code uses jPDFSecure library but could very easily be adapted […]

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Digital signatures and PDF/A compliance

Converting to PDF/A an existing Signed Document It is not possible to convert an existing PDF document that is already signed to PDF/A. This is because any changes that you make to a PDF even if it’s only adding PDF/A tags information in the metadata would invalidate the signature. If your PDF is already signed, […]

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Clear and delete signature fields in a PDF document using Java

This is sample Java program showing how to clear and delete signature fields in a PDF using Qoppa’s PDF library jPDFProcess. The jPDFProcess’ public API does not give a direct access to deleting fields in a PDF, but when deleting widgets which are the annotation associated with a field on a PDF page, it will […]

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Support multiple entries / layers in signature appearance stream

Multiple Layers in Digital Signatures Following an old format, digital signature field will sometimes define an appearance containing multiple entries / layers to be turned on or off based on the signature validity by the application at display time: n0: Background layer. n1: Validity layer, used for the unknown and valid state; contains, for instance, […]

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Customizing the signing process in jPDFNotes and jPDFEditor

Q: Is it possible to change the workflow of the signing process in jPDFNotes? A: Yes, you can customize the signature process.  What you are seeing right now is the default implementation of signing a field, which works from a file and prompts the end user to save the file right after signing.  However, you […]

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Multiple digital signatures on a PDF document

Q: I am using your Java library jPDFSecure to add 2 digital signatures to a PDF document (sign, save, sign again and save) but only the last signature shows as valid, the first signature is showing as invalid. Am I doing anything wrong? This KB entry applies to the following Java libraries and components: jPDFProcess, […]

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Code Sample: Sign PDF Using Windows IDs

Windows maintains a certificate and digital ID store. Digital IDs in the store can come from certificate authorities, or can come from USB hardware tokens. Our Java libraries jPDFSecure, jPDFProcess and visual components jPDFNotes or jPDFEditor can apply a digital signature to a PDF document using a digital ID from the Windows certificate store. Here is sample java code showing how to retrieve […]

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Code Sample: Apply digital signature to a PDF document in Java

Q: How can I add a digital signature to a document using Qoppa’s java library jPDFSecure? A: This Java program loads a document, then loads a digital ID from a PKCS#12 file, and then creates and signs a signature field on the first page of the document. // Load the document PDFSecure pdfDoc = new […]

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Certify PDF document / Add a certifying signature

Q: Is it possible to certify a PDF document with Qoppa’s libraries and componentsA: As of version 2013R2, it is possible to add a certifying signature using our libraries jPDFProcess, jPDFSecure, jPDFNotes and jPDFEditor. What is a certifying signature? A certifying signature is a digital signature. A certifying signature has to be the first applied […]

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Apply Digital Signature on a PDF document using USB hardware token PKCS 11

Q: Can jPDFSecure apply digital signatures using a hardware token? A: Yes, our 2 java PDF libraries jPDFSecure and jPDFProcess can apply a digital signature to PDF documents using a hardware token through PKCS#11. Sample Code // Load token configuration file and register provider String configName = "pkcs11.cfg"; Provider p = new sun.security.pkcs11.SunPKCS11(configName); Security.addProvider(p);   // Create key store […]

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