我正在尝试在Web应用程序中实现数字签名，例如Bruno Lowagie在白皮书中提供的示例。
4.3.3使用客户端上创建的签名在服务器上签名文档
预签名 - 客户端要求服务器提供哈希值。
签名后 - 客户端将签名的字节发送到服务器。
在这个例子中，每件事情都运行良好，但是当我们在签名后尝试打开pdf时 签名验证过程中出现错误错误。验证时遇到错误：内部加密库错误。错误代码：0x2726
这是我的代码：
客户端：
KeyStore eks = loadKeyStoreFromSmartCard("abc@123");
// Check if X.509 certification chain is available
Certificate[] certChain = new X509Certificate[1];
certChain[0] = getcert_eToken(null, eks);
String strCertificate = encodeX509CertChainToBase64(certChain);
ByteArrayOutputStream byteStream = new ByteArrayOutputStream(8192);
PrintWriter out = new PrintWriter(byteStream, true);
String postData = "certChain=" + strCertificate;
try {
HttpURLConnection connection = null;
URL dataURL = null;
dataURL = new URL("http://localhost:8085/Digital-Server/PreSignservlet");
connection = (HttpURLConnection) dataURL.openConnection();
connection.setRequestProperty("User-Agent",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows 2000)");
connection.setFollowRedirects(true);
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false);
connection.setAllowUserInteraction(false);
connection.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded");
connection.setRequestProperty("Content-Language", "en-US");
connection.setRequestProperty("Cookie", cookie);
connection.connect();
out.print(postData);
out.flush();
out.close();
byteStream.writeTo(connection.getOutputStream());
InputStream in = connection.getInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int read;
byte[] data = new byte[256];
while ((read = in.read(data)) != -1) {
baos.write(data, 0, read);
}
byte[] hash = baos.toByteArray();
PrivateKey privateKey = getprivate_eToken(null, eks);
// we sign the bytes received from the server
Signature sig = Signature.getInstance("SHA256withRSA");
sig.initSign(privateKey);
sig.update(hash);
data = sig.sign();
// --------------------------------------------
connection.disconnect();
in.close();
//Calling Post Sign Servelet
dataURL = new URL("http://localhost:8085/Digital-Server/PostSignservlet");
connection = (HttpURLConnection) dataURL.openConnection();
connection.setRequestProperty("User-Agent",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows 2000)");
connection.setFollowRedirects(true);
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false);
connection.setAllowUserInteraction(false);
connection.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded");
connection.setRequestProperty("Content-Language", "en-US");
connection.setRequestProperty("Cookie", cookie);
connection.connect();
out.flush();
out.close();
byteStream.writeTo(connection.getOutputStream());
byteStream.write(data);
in = connection.getInputStream();
OutputStream outputStream = new FileOutputStream(
"D:\\Digital Signature\\Digital-Server\\WebContent\\WEB-INF\\result\\jaihanuman.pdf");
// int read = 0;
byte[] bytes = new byte[8192];
while ((read = in.read(bytes)) != -1) {
outputStream.write(bytes, 0, read);
}
System.out.println("Done!");
预设servlet：
Certificate[] chain = decodeX509CertChainToBase64(cert);
// we create a reader and a stamper
ServletContext context = getServletContext();
String fullPath = context.getRealPath("/WEB-INF/result/hello.pdf");
PdfReader reader = new PdfReader(fullPath);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
PdfStamper stamper = PdfStamper.createSignature(reader, baos, '\0');
// we create the signature appearance
PdfSignatureAppearance sap = stamper.getSignatureAppearance();
sap.setReason("Test");
sap.setLocation("On a server!");
sap.setVisibleSignature(new Rectangle(72,737,400,780), 1, "sig");
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);
// We store the objects we'll need for post signing in a session
HttpSession session = req.getSession(true);
session.setAttribute("sgn", sgn);
session.setAttribute("hash", hash);
session.setAttribute("cal", cal);
session.setAttribute("sap", sap);
session.setAttribute("baos", baos);
// we write the hash that needs to be signed to the HttpResponse output
OutputStream os = resp.getOutputStream();
os.write(sh, 0, sh.length);
os.flush();
os.close();
}
catch(Exception ex)
{
ex.printStackTrace();
}
System.out.println("end of pre sign servelet---------------");
发布签名servlet：
try
{
// we get the objects we need for postsigning from the session
System.out.println("call post servelet1");
HttpSession session = req.getSession(false);
PdfPKCS7 sgn = (PdfPKCS7)session.getAttribute("sgn");
byte[] hash = (byte[])session.getAttribute("hash");
Calendar cal = (Calendar)session.getAttribute("cal");
PdfSignatureAppearance sap =(PdfSignatureAppearance) session.getAttribute("sap");
ByteArrayOutputStream os =(ByteArrayOutputStream) session.getAttribute("baos");
session.invalidate();
// we read the signed bytes
ByteArrayOutputStream baos = new ByteArrayOutputStream();
InputStream is = req.getInputStream();
int read;
byte[] data = new byte[256];
while ((read = is.read(data, 0, data.length)) != -1) {
baos.write(data, 0, read);
}
// we complete the PDF signing process
sgn.setExternalDigest(baos.toByteArray(), null, "RSA");
byte[] encodedSig = sgn.getEncodedPKCS7(hash, cal, null, null, null, CryptoStandard.CADES);
byte[] paddedSig = new byte[8192];
System.arraycopy(encodedSig, 0, paddedSig, 0, encodedSig.length);
PdfDictionary dic2 = new PdfDictionary();
dic2.put(PdfName.CONTENTS, new PdfString(paddedSig).setHexWriting(true));
sap.close(dic2);
// we write the signed document to the HttpResponse output stream
// let's write the file in memory to a file anyway
ServletContext context = getServletContext();
String fullPath = context.getRealPath("/WEB-INF/result/sign.pdf");
byte[] pdf = os.toByteArray();
OutputStream sos = resp.getOutputStream();
sos.write(pdf, 0, pdf.length);
sos.flush();
sos.close();
/*OutputStream sos = new FileOutputStream(fullPath);
os.writeTo(sos);
sos.flush();
sos.close();*/
}
catch(Exception ex)
{
ex.printStackTrace();
}
System.out.println("call post servelet2");
在这里，我正在做一件额外的事情，我在发送之前将证书链编码为 base64 委托servlet。
答案 0 :(得分：1)
您的代码有些令人困惑：
客户端代码在certChain中检索仅供签名者证书的证书链，base64将其编码为strCertificate，在其前面添加“certChain =”并将该字符串放入postData 。然后它会打开与PreSignservlet的连接，并使用中间人ByteArrayOutputStream byteStream以复杂的方式发送数据（为什么不简单地将postData.getBytes()写入connection.getOutputStream() ）。
不幸的是，您既不关闭输出流也不添加内容长度标头。因此，servlet可能难以识别输入结束。但这似乎不是当前的问题。
现在，您按原样获取servlet返回的数据（即不进行解码），并将其提供给签名创建。然后打开与PostSignservlet的连接以将签名字节发送到。
到目前为止它是有道理的。
但是您现在不是将签名数据发送到之前已经发送的信息（编码证书）到该servlet，然后将签名添加到本地byteStream！
为什么不简单地将签名写在data到connection.getOutputStream()？
最终，您将检索servlet的输出作为结果PDF。
您将证书而非实际签名写入PostSignservlet将解释为什么结果PDF中的CMS签名容器SignerInfo包含一个看起来像“certChain = MIIDKT ...”的“签名”值，就像你的base64编码证书一样。