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javapdfitextdigital-signature

Verify if a PDF is digitally signed with iText

As the title says I want to know if a given PDF file is already digitally signed.

I used iText to sign it but I'm not able to know if it is already signed to eventually resign it or perform other actions.

Is there a way to do it simply (possibly using iText)?

Solution

  • Using iText:

    PdfReader reader = new PdfReader(...);
AcroFields acroFields = reader.getAcroFields();
List<String> signatureNames = acroFields.getSignatureNames();

    Now signatureNames contains the names of all reachable signature fields containing signatures, cf. the JavaDoc:

    /**
 * Gets the field names that have signatures and are signed.
 *
 * @return the field names that have signatures and are signed
 */
public ArrayList<String> getSignatureNames()