XML-Signature 语法和签名

一段  XML-signature  的 demo：

<Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
    <SignedInfo>
        <!-- 规范化的算法 -->
        <CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
        <!-- 签名算法：rsa-sha1 -->
        <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/>
        <!-- 确定待签名的引用资源 -->
        <Reference URI="#_d71a3a8e9fcc45c9e9d248ef7049393fc8f04e5f75">
        <!-- 转换算法 -->
            <Transforms>
                <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/>
                <Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
            </Transforms>
            <!-- 消息摘要的算法，比如：SHA1 -->
            <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
            <!-- 消息摘要 -->
            <DigestValue>k9i4QGA5BDFkW5I+Igr8hR1ibZs=</DigestValue>
        </Reference>
    </SignedInfo>
    <!--  签名内容 -->
    <SignatureValue>
        PLIKGZOFbMt8qEM1yw6f/Uct7R9Xd8KWZXw5925gIJdA8+q9MfY34+sQwDcy1Tqnxzak6hx6A6olQr+zJCQH8O/S+sDgCEUhXG+PFU4j2pxnnYqwI3jKc2yeT7A7f8ShStgwN7IgjZ0TFLx2TO3tlZ76 2GwFHNN0lH9ohtAv8Zs=
    </SignatureValue>
    <!-- KeyInfo 元素可选，表明签名的公钥信息 -->
    <KeyInfo>
        <X509Data>
            <X509Certificate>
            MIICaDCCAdGgAaIBAgIEfnIVCzANBgkqhkiG9w0BAQsFADBnMQ4wDAYDVQQGEwVjaGluYTEQMA4G A1UECBMHYmVpamluZzEQMA4GA1UEBxMHYmVpamluZzERMA8GA1UEChMIYmV3aW5uZXIxDTALBgNV BAsTBGJ3MzAxDzANBgNVBAMTBnhpYW9zeTAeFw0xNzExMDgwOTU1NDVaFw0yNzExMDYwOTU1NDVa MGcxDjAMBgNVBAYTBWNoaW5hMRAwDgYDVQQIEwdiZWlqaW5nMRAwDgYDVQQHEwdiZWlqaW5nMREw DwYDVQQKEwhiZXdpbm5lcjENMAsGA1UECxMEYnczMDEPMA0GA1UEAxMGeGlhb3N5MIGfMA0GCSqG SIb3DQEBAQUAA4GNADCBiQKBgQCgmrEMgAMY7zygYqBtYzMal0vTVsQNyjGkD3tbA+pEk18YfN13 UEBoqrp/XQiR4v334xqHjdtG8lxDzEUJ4fQippxMpw6Fab45pz6uOr33DI6X3IwLPxtb7q1MyIj3 TXBY6R01rwIaE+G8/5z76mN5qq4/lhoY3bs0D06pwUSSSQIDAQABoyEwHzAdBgNVHQ4EFgQURAyK 5AjoSEOk32ceEloftZ8TiWcwDQYJKoZIhvcNAQELBQADgYEAZuNWxMO8HOItqAoCI8f6+PfjbL/7 xTwDjs8PxnermmVjACx5JiW0O98M0D5Guo0OABf8mMxiDYQvRwpNoEfMOXr3TjPxqioLMq+s1Nt8 0Duilqel+O6Q/XDJ8rlVdm8vPhLxWZ14FIdI8n7CuuUwUExe4Uj05shCMwgNRo6bmaU=
            </X509Certificate>
        </X509Data>
    </KeyInfo>
</Signature>

XML-signature 中的签名算法就是对  XML文档树 进行签名，说明如下：
1、确认签名内容，通过 URL 将这些内容表示为引用资源，用 Reference 标识。对于断言信息来说，其 URI 是saml:Assertion的 ID
2、对待签名的数据进行转化处理，包括执行编码规则、规范化算法等， Transform 指定了转化的算法
3、对整个断言进行消息摘要， DigestMethod 指定了消息摘要算法，消息摘要的结果保存在 DigestValue 元素中
4、构造包含 Reference 的 SignedInfo 元素
5、 CanonicalizationMethod 元素指定了规范化的算法，如果不对其进行规范化处理，验证 xml 签名时可能因为xml 结构表示不同而失败
6、计算 SignedInfo 的摘要，使用 SignatureMethod 声明的签名算法，并对其进行签名，结果保存到 SignatureValue 元素中
7、 KeyInfo 元素可选，表明签名的公钥信息

下面这个工具类实现了 XML-signature 的签名和验签

import java.io.StringWriter;
import java.security.KeyStore.PrivateKeyEntry;
import java.security.PublicKey;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
import javax.xml.crypto.dsig.CanonicalizationMethod;
import javax.xml.crypto.dsig.DigestMethod;
import javax.xml.crypto.dsig.Reference;
import javax.xml.crypto.dsig.SignatureMethod;
import javax.xml.crypto.dsig.SignedInfo;
import javax.xml.crypto.dsig.Transform;
import javax.xml.crypto.dsig.XMLSignature;
import javax.xml.crypto.dsig.XMLSignatureFactory;
import javax.xml.crypto.dsig.dom.DOMSignContext;
import javax.xml.crypto.dsig.dom.DOMValidateContext;
import javax.xml.crypto.dsig.spec.C14NMethodParameterSpec;
import javax.xml.crypto.dsig.spec.TransformParameterSpec;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import lombok.Cleanup;
import lombok.SneakyThrows;
import lombok.experimental.UtilityClass;
import lombok.extern.slf4j.Slf4j;
import org.dom4j.io.DOMWriter;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

@UtilityClass
@Slf4j
public class SignUtils {

  private static final XMLSignatureFactory XML_SIGNATURE_FACTORY = XMLSignatureFactory.getInstance("DOM");

  private static final TransformerFactory TRANSFORMER_FACTORY = TransformerFactory.newInstance();

  @SneakyThrows
  public static Reference getTransformReference(String uri) {
    DigestMethod digestMethod = XML_SIGNATURE_FACTORY.newDigestMethod(DigestMethod.SHA1, null);
    List<Transform> transforms = Collections.singletonList(XML_SIGNATURE_FACTORY.newTransform(Transform.ENVELOPED, (TransformParameterSpec) null));
    return XML_SIGNATURE_FACTORY.newReference("#" + uri, digestMethod, transforms, null, null);
  }

  @SneakyThrows
  public static SignedInfo getSignedInfo(Reference ref) {
    CanonicalizationMethod method = XML_SIGNATURE_FACTORY.newCanonicalizationMethod(CanonicalizationMethod.INCLUSIVE, (C14NMethodParameterSpec) null);
    SignatureMethod signatureMethod = XML_SIGNATURE_FACTORY.newSignatureMethod(SignatureMethod.RSA_SHA1, null);
    return XML_SIGNATURE_FACTORY.newSignedInfo(method, signatureMethod, Collections.singletonList(ref));
  }

  @SneakyThrows
  public static String sign(Document w3cDoc, PrivateKeyEntry keyEntry, SignedInfo si) {
    Optional.ofNullable(w3cDoc)
        .map(Document::getDocumentElement)
        .map(Node::getFirstChild)
        .map(Node::getFirstChild)
        .ifPresent(e -> ((Element) e).setIdAttribute("id", true));
    DOMSignContext dsc = new DOMSignContext(keyEntry.getPrivateKey(), Optional.ofNullable(w3cDoc).map(Document::getDocumentElement).get());
    XMLSignature signature = XML_SIGNATURE_FACTORY.newXMLSignature(si, null);
    signature.sign(dsc);
    @Cleanup StringWriter strWriter = new StringWriter();
    TRANSFORMER_FACTORY.newTransformer().transform(new DOMSource(w3cDoc), new StreamResult(strWriter));
    return strWriter.toString();
  }

  @SneakyThrows
  public static boolean checkSign(Node signNode, PublicKey publicKey) {
    Optional.ofNullable(signNode.getPreviousSibling()).ifPresent(e -> ((Element) e).setIdAttribute("id", true));
    DOMValidateContext valContext = new DOMValidateContext(publicKey, signNode);
    XMLSignature signature = XML_SIGNATURE_FACTORY.unmarshalXMLSignature(valContext);
    return signature.validate(valContext);
  }

  @SneakyThrows
  public static org.w3c.dom.Document convert(org.dom4j.Document doc) {
    log.info("org.dom4j.Document,outXml:[{}]", doc.asXML());
    return new DOMWriter().write(doc);
  }

}

下面这个类实现了公、私钥证书的加载：

import java.io.FileInputStream;
import java.io.InputStream;
import java.security.KeyStore;
import java.security.KeyStore.PrivateKeyEntry;
import java.security.PublicKey;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.concurrent.atomic.AtomicBoolean;
import lombok.Cleanup;
import lombok.SneakyThrows;

public final class X509CertificationLoader implements CertificationLoader {

  public static final CertificationLoader INSTANCE = new X509CertificationLoader();

  private PrivateKeyEntry privateKeyEntry;
  private PublicKey publicKey;

  private AtomicBoolean isPrivateKeyInitiated = new AtomicBoolean(false);
  private AtomicBoolean isPublicKeyInitiated = new AtomicBoolean(false);

  private X509CertificationLoader() {
  }

  @Override
  @SneakyThrows
  public PrivateKeyEntry getPrivateKey(CertInfo certInfo) {
    if (null != privateKeyEntry) {
      return privateKeyEntry;
    }
    if (isPrivateKeyInitiated.compareAndSet(false, true)) {
      KeyStore ks = KeyStore.getInstance(KEY_STORE_TYPE);
      @Cleanup InputStream fileInputStream = new FileInputStream(certInfo.getPrivateKeyFile());
      final char[] passwdChars = certInfo.getPasswd().toCharArray();
      ks.load(fileInputStream, passwdChars);
      privateKeyEntry = (PrivateKeyEntry) ks.getEntry(ks.aliases().nextElement(), new KeyStore.PasswordProtection(passwdChars));
    }
    return privateKeyEntry;
  }

  @Override
  @SneakyThrows
  public PublicKey getPublicKey(CertInfo certInfo) {
    if (null != publicKey) {
      return publicKey;
    }
    if (isPublicKeyInitiated.compareAndSet(false, true)) {
      @Cleanup InputStream fin = new FileInputStream(certInfo.getPublicKeyFile());
      CertificateFactory f = CertificateFactory.getInstance(CERTIFICATE_TYPE_NAME);
      X509Certificate certificate = (X509Certificate) f.generateCertificate(fin);
      publicKey = certificate.getPublicKey();
    }
    return publicKey;
  }

}

import java.security.KeyStore.PrivateKeyEntry;
import java.security.PublicKey;

public interface CertificationLoader {

  String KEY_STORE_TYPE = "PKCS12";

  String CERTIFICATE_TYPE_NAME = "X.509";

  /**
   * 获取包含私钥证书的 KeyStore
   *
   * @param certInfo 证书文件信息 {@link CertInfo}
   * @return KeyStore {@link PrivateKeyEntry}
   */
  PrivateKeyEntry getPrivateKey(CertInfo certInfo);

  /**
   * 获取 X509 格式的公钥证书
   *
   * @param certInfo 证书文件信息 {@link CertInfo}
   * @return 公钥证书 {@link PublicKey}
   */
  PublicKey getPublicKey(CertInfo certInfo);

}