Java 类com.itextpdf.text.pdf.security.DigestAlgorithms 实例源码

/**
 * <a href="http://stackoverflow.com/questions/36589698/error-while-digitally-signing-a-pdf">
 * Error while digitally signing a PDF
 * </a>
 * <p>
 * Tried to reproduce the OP's issue with my own test PDF and key. But it worked alright.
 * </p>
 */
@Test
public void signLikeJackSparrow() throws GeneralSecurityException, IOException, DocumentException
{
    final String SRC      = "src/test/resources/mkl/testarea/itext5/extract/test.pdf";
    final String DEST     = new File(RESULT_FOLDER, "test-JackSparrow-%s.pdf").getPath();

    C2_01_SignHelloWorld_sign(SRC, String.format(DEST, 1), chain, pk, DigestAlgorithms.SHA256, "BC", CryptoStandard.CMS, "Signed for Testing", "Universe");
    C2_01_SignHelloWorld_sign(SRC, String.format(DEST, 2), chain, pk, DigestAlgorithms.SHA512, "BC", CryptoStandard.CMS, "Test 2", "Universe");
    C2_01_SignHelloWorld_sign(SRC, String.format(DEST, 3), chain, pk, DigestAlgorithms.SHA256, "BC", CryptoStandard.CADES, "Test 3", "Universe");
}

public DigestInfo preSign(List<DigestInfo> arg0, List<X509Certificate> certificates)
        throws NoSuchAlgorithmException {
    System.out.println("SignatureServiceImpl::preSign");

    HttpSession session = getSession();
    SignatureRequest request = (SignatureRequest)session.getAttribute(BeidConstants.SIGNATUREREQUEST_SESSION_NAME);
    ContentStream content = request.getDocument().getContentStream();

    try 
    {
        Certificate[] chain = new Certificate[certificates.size()];
        int index = 0;
        for (X509Certificate cert: certificates)
        {
            //System.out.println("CERT: "+cert);
            chain[index++] = cert;
        }

        // we create a reader and a stamper
        PdfReader reader = new PdfReader(content.getStream());
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        PdfStamper stamper = PdfStamper.createSignature(reader, baos, '\0');
        // we create the signature appearance
        PdfSignatureAppearance sap = stamper.getSignatureAppearance();

        request.fillAppearance(sap, reader);

        sap.setCertificate(chain[0]);
        // we create the signature infrastructure
        PdfSignature dic = new PdfSignature(PdfName.ADOBE_PPKLITE, PdfName.ADBE_PKCS7_DETACHED);
        dic.setReason(sap.getReason());
        dic.setLocation(sap.getLocation());
        dic.setContact(sap.getContact());
        dic.setDate(new PdfDate(sap.getSignDate()));
        sap.setCryptoDictionary(dic);
        HashMap<PdfName, Integer> exc = new HashMap<PdfName, Integer>();
        exc.put(PdfName.CONTENTS, new Integer(8192 * 2 + 2));
        sap.preClose(exc);
        ExternalDigest externalDigest = new ExternalDigest() {
            public MessageDigest getMessageDigest(String hashAlgorithm)
                    throws GeneralSecurityException {
                return DigestAlgorithms.getMessageDigest(hashAlgorithm,
                        null);
            }
        };
        PdfPKCS7 sgn = new PdfPKCS7(null, chain, "SHA256", null, externalDigest, false);
        InputStream data = sap.getRangeStream();
        byte hash[] = DigestAlgorithms.digest(data, externalDigest.getMessageDigest("SHA256"));
        Calendar cal = Calendar.getInstance();
        byte[] sh = sgn.getAuthenticatedAttributeBytes(hash, cal, null, null, CryptoStandard.CMS);
        sh = MessageDigest.getInstance("SHA256", "BC").digest(sh);

        // We store the objects we'll need for post signing in a session
        session.setAttribute(BeidConstants.SIGNATURE_SESSION_NAME, sgn);
        session.setAttribute(BeidConstants.HASH_SESSION_NAME, hash);
        session.setAttribute(BeidConstants.CAL_SESSION_NAME, cal);
        session.setAttribute(BeidConstants.SAP_SESSION_NAME, sap);
        session.setAttribute(BeidConstants.BAOS_SESSION_NAME, baos);
        DigestInfo info = new DigestInfo(sh, "SHA-256", "BeidSign");

        return info;
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }

    return null;
}