启用 iText LTV - 如何添加更多 CRL？

Question

我需要启用签名的 pdf LTV。签名证书具有三个级别（根/公共/个人）的链。我知道有必要在pdf中添加证书的OCSP和CRL（root除外）。

• 我可以使用基本的 LtvVerification.addVerification() 方法吗？ 如果我一次添加两个 CRL，结果 PDF 只是一秒钟。如果我改变订单，还有第二个。 如果我在两次运行中添加 CRL，它将以相同的方式结束 - 在 pdf 中，CRL 仍然作为第二个添加。 我认为“添加”不会覆盖以前的状态..

• 如何正确使用LtvVerification.merge()方法？在添加第一个/第二个/两个 CRL 之前/之后？

• 或者我只能使用替代方法 LtvVerification.addVerification(String signatureName, Collection ocsps, Collection crls, Collection certs)？

非常感谢您的提示。

源代码：

public void addLtv(String src, String dest) throws IOException, DocumentException, GeneralSecurityException
{

    BouncyCastleProvider provider = new BouncyCastleProvider();
    Security.addProvider(provider);

    PdfReader r = new PdfReader(src);
    System.out.println("Source file: " + src);
    FileOutputStream fos = new FileOutputStream(dest);
    PdfStamper stp = new PdfStamper(r, fos, '\0', true);
    LtvVerification v = stp.getLtvVerification();
    AcroFields fields = stp.getAcroFields();

    ArrayList<String> names = fields.getSignatureNames();
    String sigName = names.get(names.size() - 1);
    System.out.println("found signature: " + sigName);
    PdfPKCS7 pkcs7 = fields.verifySignature(sigName);

    //add LTV
    OcspClient ocsp = new OcspClientBouncyCastle();
    CrlClient crlClient1 = new CrlClientOnline("http://www.postsignum.cz/crl/psrootqca2.crl");
    ArrayList<CrlClient> crllist = new ArrayList<CrlClient>();
    crllist.add(crlClient1);
    CrlClient crlClient2 = new CrlClientOnline("http://www.postsignum.cz/crl/pspublicca2.crl");
    crllist.add(crlClient2);
    System.out.println("crllist.size=" + crllist.size());

    if (pkcs7.isTsp())
    {
        for (CrlClient crlclient : crllist)
        {
            if (v.addVerification(sigName, new OcspClientBouncyCastle(), crlclient,
                    LtvVerification.CertificateOption.SIGNING_CERTIFICATE,
                    LtvVerification.Level.CRL,
                    LtvVerification.CertificateInclusion.NO)) {
                System.out.println("crl " + crlclient.toString() + " added to timestamp");
            }
        }

    } else{


        for (String name : names)
        {
            for (int i = 0; i < crllist.size(); i++) {
                if (v.addVerification(name, ocsp, crllist.get(i),
                        LtvVerification.CertificateOption.WHOLE_CHAIN,
                        LtvVerification.Level.CRL,
                        LtvVerification.CertificateInclusion.NO)) {
                    System.out.println("crl " + crllist.get(i).toString() + " added to " + name);
                }

                if (i > 0) {
                    System.out.println("found verification, merge");
                    v.merge();
                }

            }
        }
    }

    stp.close();
}

Answer 1

如果您想向LtvVerification.addVerification 提供多个 CRL，则不为每个 CRL 调用一次该方法，而是对所有 CRL 调用一次 em>。

为此，CrlClientOnline 也接受多个 URL：

/**
 * Creates a CrlClientOnline instance using one or more URLs.
 */
public CrlClientOnline(String... crls)

因此，通过使用此构造函数，我们可以简化并修复您的代码

PdfReader r = new PdfReader(src);
FileOutputStream fos = new FileOutputStream(dest);
PdfStamper stp = new PdfStamper(r, fos, '\0', true);
LtvVerification v = stp.getLtvVerification();
AcroFields fields = stp.getAcroFields();

ArrayList<String> names = fields.getSignatureNames();
String sigName = names.get(names.size() - 1);
System.out.println("found signature: " + sigName);
PdfPKCS7 pkcs7 = fields.verifySignature(sigName);

//add LTV
OcspClient ocsp = new OcspClientBouncyCastle();
CrlClient crlClient = new CrlClientOnline("http://www.postsignum.cz/crl/psrootqca2.crl", "http://www.postsignum.cz/crl/pspublicca2.crl");

if (pkcs7.isTsp())
{
    if (v.addVerification(sigName, new OcspClientBouncyCastle(), crlClient,
            LtvVerification.CertificateOption.SIGNING_CERTIFICATE,
            LtvVerification.Level.CRL,
            LtvVerification.CertificateInclusion.NO))
    {
        System.out.println("crl " + crlClient.toString() + " added to timestamp");
    }
}
else
{
    for (String name : names)
    {
        if (v.addVerification(name, ocsp, crlClient,
                LtvVerification.CertificateOption.WHOLE_CHAIN,
                LtvVerification.Level.CRL,
                LtvVerification.CertificateInclusion.NO))
        {
            System.out.println("crl " + crlClient.toString() + " added to " + name);
        }
    }
}
stp.close();

(AddLtvCrls.java, 方法addLtvFixed)

将其应用于您的示例文件，我们得到：

---

对于某些背景，LtvVerification.addVerification 将其拥有的信息存储为相关签名所需的验证信息。多次调用它只会得到最后一次计数的信息。

在这里调用 LtvVerification.merge 也无济于事，因为它只是将旧版本中不同签名所需的验证信息合并到新的验证相关信息部分。