PDF签名通过带锁的PDFBox

Question

我想通过使用锁签署一个pdf文件。我正在使用PDFBox 2.0.9

我想实现的流量是：

null

PDSignatureField signatureField = getSignatureField(pdDocument, pdSignature);
if (signatureField != null) {
    COSDictionary lockDict = new COSDictionary();
    lockDict.setItem(COSName.TYPE, COS_NAME_SIG_FIELD_LOCK);
    lockDict.setItem(COS_NAME_ACTION, COS_NAME_EXCLUDE);

    COSArray lockFields = new COSArray();
    lockFields.add(new COSString("textbox1"));

    lockDict.setItem(COS_NAME_FIELDS, lockFields);

    signatureField.getCOSObject().setItem(COS_NAME_LOCK, lockDict);

    COSDictionary transformParams = new COSDictionary(lockDict);
    transformParams.setItem(COSName.TYPE, COSName.getPDFName("TransformParams"));
    transformParams.setItem(COSName.V, COSName.getPDFName("1.2"));
    transformParams.setDirect(true);
    COSDictionary sigRef = new COSDictionary();
    sigRef.setItem(COSName.TYPE, COSName.getPDFName("SigRef"));
    sigRef.setItem(COSName.getPDFName("TransformParams"), transformParams);
    sigRef.setItem(COSName.getPDFName("TransformMethod"), COSName.getPDFName("FieldMDP"));
    //sigRef.setItem(COSName.getPDFName("Data"), pdDocument.getDocumentCatalog());
    sigRef.setDirect(true);
    COSArray referenceArray = new COSArray();
    referenceArray.add(sigRef);
    pdSignature.getCOSObject().setItem(COSName.getPDFName("Reference"), referenceArray);

}

我可以签名，更改字段值，然后再次签名，签名就可以了。问题是当我在第二个签名之后更改字段的值时，签名仍然有效。我希望在上次更改后，第二个签名一定是无效的。

Answer 1

问题出在我的代码上，因为这个代码每次都会添加排除。当我像下面这样编码（我的第一个签名名是签名1）时，一切都像预期的那样变得正常。

    public static final COSName COS_NAME_LOCK = COSName.getPDFName("Lock");
    public static final COSName COS_NAME_ACTION = COSName.getPDFName("Action");
    public static final COSName COS_NAME_ALL = COSName.getPDFName("All");
    public static final COSName COS_NAME_INCLUDE = COSName.getPDFName("Include");
    public static final COSName COS_NAME_EXCLUDE = COSName.getPDFName("Exclude");
    public static final COSName COS_NAME_FIELDS = COSName.getPDFName("Fields");
    public static final COSName COS_NAME_SIG_FIELD_LOCK = COSName.getPDFName("SigFieldLock");


        PDSignatureField signatureField = getSignatureField(pdDocument, pdSignature);
        if (signatureField != null) {
            COSDictionary lockDict = new COSDictionary();
            lockDict.setItem(COSName.TYPE, COS_NAME_SIG_FIELD_LOCK);
            lockDict.setItem(COS_NAME_ACTION, COS_NAME_EXCLUDE);

            COSArray lockFields = new COSArray();
            if (pdSignature.getName().equals("Signature1")) {
                lockFields.add(new COSString("textbox1"));
            }

            lockDict.setItem(COS_NAME_FIELDS, lockFields);

            signatureField.getCOSObject().setItem(COS_NAME_LOCK, lockDict);

            COSDictionary transformParams = new COSDictionary(lockDict);
            transformParams.setItem(COSName.TYPE, COSName.getPDFName("TransformParams"));
            transformParams.setItem(COSName.V, COSName.getPDFName("1.2"));
            transformParams.setDirect(true);
            COSDictionary sigRef = new COSDictionary();
            sigRef.setItem(COSName.TYPE, COSName.getPDFName("SigRef"));
            sigRef.setItem(COSName.getPDFName("TransformParams"), transformParams);
            sigRef.setItem(COSName.getPDFName("TransformMethod"), COSName.getPDFName("FieldMDP"));
            sigRef.setDirect(true);
            COSArray referenceArray = new COSArray();
            referenceArray.add(sigRef);
            pdSignature.getCOSObject().setItem(COSName.getPDFName("Reference"), referenceArray);

        }