LoginSignup
2
2

Delete article

Deleted articles cannot be recovered.

Draft of this article would be also deleted.

Are you sure you want to delete this article?

More than 3 years have passed since last update.

@haru52

JavaでXML署名を実装する

Last updated at Posted at 2018-10-30

JavaでXML署名を実装する必要があったのでまとめておく。
基本的には以下のコードをJava 11で実際に動くように少しいじっただけ。

環境

  • macOS 10.13.6 (High Sierra)
  • OpenSSL 1.0.2p
  • Java 11.0.1 (OpenJDK)

準備：秘密鍵・証明書の作成

RSA秘密鍵・X.509公開鍵証明書のペアを作成
$ openssl req -out alice.crt -nodes -keyout alice.pem -newkey rsa:4096 -sha256 -x509 -days 365

証明書の確認

$ openssl x509 -in alice.crt -noout -text

Javaで秘密鍵を読み込むには、秘密鍵をPKCS #8・DER形式に変換する必要がある。
$ openssl pkcs8 -in alice.pem -outform DER -out alice.pk8 -topk8 -nocrypt

ファイルの状況は次の通り。

  • alice.pk8：PKCS #8・DER形式の秘密鍵（RSA 4096 bit）
  • alice.crt：X.509公開鍵証明書（RSA・SHA-256）
  • alice.pem：PEM形式の秘密鍵（今回は使わない）

サンプルXMLファイル

envelope.xml
<!-- ref. https://docs.oracle.com/javase/6/docs/technotes/guides/security/xmldsig/envelope.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<Envelope xmlns="urn:envelope">
</Envelope>

XML署名プログラム

GenEnveloped.java
// ref. https://docs.oracle.com/javase/6/docs/technotes/guides/security/xmldsig/GenEnveloped.java

import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.dom.DOMSignContext;
import javax.xml.crypto.dsig.keyinfo.*;
import javax.xml.crypto.dsig.spec.*;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.security.*;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.security.interfaces.RSAPrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Collections;
import java.util.List;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

public class GenEnveloped {
  public static void main(String[] args) {
    if (args.length != 4) {
      System.err.println("Usage: java GenEnveloped [input XML path] [output XML path] [private key path (pk8)] [certificate path]");
      System.exit(1);
    }

    try {
      genEnveloped(args[0], args[1], args[2], args[3]);
    } catch (Exception e) {
      System.err.println(e);
      System.exit(1);
    }
  }

  public static void genEnveloped(String inXmlPath, String outXmlPath, String privateKeyPath, String certPath) throws Exception {
    // Create a DOM XMLSignatureFactory that will be used to generate the
    // enveloped signature
    XMLSignatureFactory fac = XMLSignatureFactory.getInstance("DOM");

    // Create a Reference to the enveloped document (in this case we are
    // signing the whole document, so a URI of "" signifies that) and
    // also specify the SHA256 digest algorithm and the ENVELOPED Transform.
    DigestMethod dm = fac.newDigestMethod(DigestMethod.SHA256, null);
    List<Transform> transforms = Collections.singletonList(fac.newTransform(Transform.ENVELOPED, (TransformParameterSpec) null));
    Reference ref = fac.newReference("", dm, transforms, null, null);

    // Create the SignedInfo
    CanonicalizationMethod cm = fac.newCanonicalizationMethod(CanonicalizationMethod.INCLUSIVE_WITH_COMMENTS, (C14NMethodParameterSpec) null);
    SignatureMethod sm = fac.newSignatureMethod(SignatureMethod.RSA_SHA256, null);
    List<Reference> references = Collections.singletonList(ref);
    SignedInfo si = fac.newSignedInfo(cm, sm, references);

    // Read a RSA private key
    FileInputStream fis = new FileInputStream(privateKeyPath);
    byte[] privateKeyByte = new byte[fis.available()];
    fis.read(privateKeyByte);
    fis.close();
    PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyByte);
    KeyFactory kf = KeyFactory.getInstance("RSA");
    RSAPrivateKey privateKey = (RSAPrivateKey) kf.generatePrivate(keySpec);

    // Read a X.509 certificate
    KeyInfoFactory kif = fac.getKeyInfoFactory();
    CertificateFactory cf = CertificateFactory.getInstance("X.509");
    X509Certificate cert = (X509Certificate) cf.generateCertificate(new FileInputStream(certPath));
    X509Data x509Data = kif.newX509Data(Collections.singletonList(cert));

    // Create a KeyInfo and add the X509Data to it
    KeyInfo ki = kif.newKeyInfo(Collections.singletonList(x509Data));

    // Instantiate the document to be signed
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setNamespaceAware(true);
    Document doc = dbf.newDocumentBuilder().parse(new FileInputStream(inXmlPath));

    // Create a DOMSignContext and specify the RSA PrivateKey and
    // location of the resulting XMLSignature's parent element
    DOMSignContext dsc = new DOMSignContext(privateKey, doc.getDocumentElement());

    // Create the XMLSignature (but don't sign it yet)
    XMLSignature signature = fac.newXMLSignature(si, ki);

    // Marshal, generate (and sign) the enveloped signature
    signature.sign(dsc);

    // output the resulting document
    OutputStream os = new FileOutputStream(outXmlPath);
    TransformerFactory tf = TransformerFactory.newInstance();
    Transformer trans = tf.newTransformer();
    trans.transform(new DOMSource(doc), new StreamResult(os));
  }
}

コンパイル
$ javac GenEnveloped.java

Usage
$ java GenEnveloped [input XML path] [output XML path] [private key path (pk8)] [certificate path]

実行例
$ java GenEnveloped envelope.xml envelopedSignature.xml alice.pk8 alice.crt

XML署名検証プログラム

Validate.java
// ref. https://docs.oracle.com/javase/6/docs/technotes/guides/security/xmldsig/Validate.java

import javax.xml.crypto.*;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.dom.DOMValidateContext;
import javax.xml.crypto.dsig.keyinfo.*;
import java.io.FileInputStream;
import java.security.*;
import java.security.cert.X509Certificate;
import java.util.Iterator;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;

public class Validate {
  public static void main(String[] args) {
    if (args.length != 1) {
      System.err.println("Usage: java Validate [input XML path]");
      System.exit(1);
    }

    try {
      validate(args[0]);
    } catch (Exception e) {
      System.err.println(e);
      System.exit(1);
    }
  }

  public static boolean validate(String inXmlPath) throws Exception {
    // Instantiate the document to be validated
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setNamespaceAware(true);
    Document doc = dbf.newDocumentBuilder().parse(new FileInputStream(inXmlPath));

    // Find Signature element
    NodeList nl = doc.getElementsByTagNameNS(XMLSignature.XMLNS, "Signature");
    if (nl.getLength() == 0)
      throw new Exception("Cannot find Signature element");

    // Create a DOM XMLSignatureFactory that will be used to unmarshal the
    // document containing the XMLSignature
    XMLSignatureFactory fac = XMLSignatureFactory.getInstance("DOM");

    // Create a DOMValidateContext and specify a KeyValue KeySelector
    // and document context
    DOMValidateContext valContext = new DOMValidateContext(new KeyValueKeySelector(), nl.item(0));

    // unmarshal the XMLSignature
    XMLSignature signature = fac.unmarshalXMLSignature(valContext);

    // Validate the XMLSignature (generated above)
    boolean coreValidity = signature.validate(valContext);

    // Check core validation status
    if (!coreValidity) {
      System.err.println("Signature failed core validation");
      boolean sv = signature.getSignatureValue().validate(valContext);
      System.out.println("signature validation status: " + sv);
      // check the validation status of each Reference
      Iterator i = signature.getSignedInfo().getReferences().iterator();
      for (int j = 0; i.hasNext(); j++) {
        boolean refValid = ((Reference) i.next()).validate(valContext);
        System.out.println("ref[" + j + "] validity status: " + refValid);
      }
    } else
      System.out.println("Signature passed core validation");
    return coreValidity;
  }

  /**
   * KeySelector which retrieves the public key out of the
   * KeyValue element and returns it.
   * NOTE: If the key algorithm doesn't match signature algorithm,
   * then the public key will be ignored.
   */
  private static class KeyValueKeySelector extends KeySelector {
    public KeySelectorResult select(KeyInfo keyInfo, KeySelector.Purpose purpose, AlgorithmMethod method, XMLCryptoContext context) throws KeySelectorException {
      if (keyInfo == null)
        throw new KeySelectorException("Null KeyInfo object!");
      SignatureMethod sm = (SignatureMethod) method;

      for (Object keyInfoContent : keyInfo.getContent()) {
        if (keyInfoContent instanceof X509Data) {
          for (Object x509Content : ((X509Data) keyInfoContent).getContent()) {
            X509Certificate cert = (X509Certificate) x509Content;
            PublicKey pk = cert.getPublicKey();
            // make sure algorithm is compatible with method
            if (algEquals(sm.getAlgorithm(), pk.getAlgorithm()))
              return new SimpleKeySelectorResult(pk);
          }
        }
      }
      throw new KeySelectorException("No KeyValue element found!");
    }

    static boolean algEquals(String algURI, String algName) {
      if (algName.equalsIgnoreCase("RSA") && algURI.equalsIgnoreCase(SignatureMethod.RSA_SHA256))
        return true;
      else if (algName.equalsIgnoreCase("DSA") && algURI.equalsIgnoreCase(SignatureMethod.DSA_SHA1))
        return true;
      else if (algName.equalsIgnoreCase("RSA") && algURI.equalsIgnoreCase(SignatureMethod.RSA_SHA1))
        return true;
      else
        return false;
    }
  }

  private static class SimpleKeySelectorResult implements KeySelectorResult {
    private PublicKey pk;

    SimpleKeySelectorResult(PublicKey pk) {
      this.pk = pk;
    }

    public Key getKey() {
      return pk;
    }
  }
}

コンパイル
$ javac Validate.java

Usage
$ java Validate [input XML path]

実行例（検証成功）

$ java Validate envelopedSignature.xml
Signature passed core validation

実行例（検証失敗）

$ java Validate envelopedSignature.xml
Signature failed core validation
signature validation status: false
ref[0] validity status: true

P.S.

ソースコードはこちら。
haru52/xmldsig

References

2
2
0

Register as a new user and use Qiita more conveniently

  1. You get articles that match your needs
  2. You can efficiently read back useful information
  3. You can use dark theme
What you can do with signing up
Sign upLogin
2
2

Delete article

Deleted articles cannot be recovered.

Draft of this article would be also deleted.

Are you sure you want to delete this article?