Wednesday, March 05, 2014

Signing SOAP Messages - Generation of Enveloped XML Signatures

Digital signing is a widely used mechanism to make digital contents authentic. By producing a digital signature for some content, we can let another party capable of validating that content. It can provide a guarantee that, is not altered after we signed it, with this validation. With this sample I am to share how to generate the a signature for SOAP envelope. But of course this is valid for any other content signing as well.

Here, I will sign
  • The SOAP envelope itself
  • An attachment 
  • Place the signature inside SOAP header 
With the placement of signature inside the SOAP header which is also signed by the signature, this becomes a demonstration of enveloped signature.

I am using Apache Santuario library for signing. Following is the code segment I used. I have shared the complete sample here to to be downloaded.

public static void main(String unused[]) throws Exception {

        String keystoreType = "JKS";
        String keystoreFile = "src/main/resources/PushpalankaKeystore.jks";
        String keystorePass = "pushpalanka";
        String privateKeyAlias = "pushpalanka";
        String privateKeyPass = "pushpalanka";
        String certificateAlias = "pushpalanka";
        File signatureFile = new File("src/main/resources/signature.xml");
        Element element = null;
        String BaseURI = signatureFile.toURI().toURL().toString();
        //SOAP envelope to be signed
        File attachmentFile = new File("src/main/resources/sample.xml");

        //get the private key used to sign, from the keystore
        KeyStore ks = KeyStore.getInstance(keystoreType);
        FileInputStream fis = new FileInputStream(keystoreFile);
        ks.load(fis, keystorePass.toCharArray());
        PrivateKey privateKey =

                (PrivateKey) ks.getKey(privateKeyAlias, privateKeyPass.toCharArray());
        //create basic structure of signature
        javax.xml.parsers.DocumentBuilderFactory dbf =
                javax.xml.parsers.DocumentBuilderFactory.newInstance();
        dbf.setNamespaceAware(true);
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(attachmentFile);
        XMLSignature sig =
                new XMLSignature(doc, BaseURI, XMLSignature.ALGO_ID_SIGNATURE_RSA_SHA1);

        //optional, but better
        element = doc.getDocumentElement();
        element.normalize();
        element.getElementsByTagName("soap:Header").item(0).appendChild(sig.getElement());

        {
            Transforms transforms = new Transforms(doc);
            transforms.addTransform(Transforms.TRANSFORM_C14N_OMIT_COMMENTS);
            //Sign the content of SOAP Envelope
            sig.addDocument("", transforms, Constants.ALGO_ID_DIGEST_SHA1);

            //Adding the attachment to be signed
            sig.addDocument("../resources/attachment.xml", transforms, Constants.ALGO_ID_DIGEST_SHA1);

        }

        //Signing procedure
        {
            X509Certificate cert =
                    (X509Certificate) ks.getCertificate(certificateAlias);
            sig.addKeyInfo(cert);
            sig.addKeyInfo(cert.getPublicKey());
            sig.sign(privateKey);
        }

        //write signature to file
        FileOutputStream f = new FileOutputStream(signatureFile);
        XMLUtils.outputDOMc14nWithComments(doc, f);
        f.close();
    }

At first it reads in the private key which is to be used in signing. To create a key pair for your own, this post  will be helpful. Then it has created the signature and added the SOAP message and the attachment as the documents to be signed. Finally it performs signing  and write the signed document to a file.

The signed SOAP message looks as follows.

<soap:Envelope xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:pj="http://www.pjxml.org/namespaces/messageHeader"
               xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"
               xmlns:xsi="http://www.w3.org/2000/10/XMLSchema-instance">
    <soap:Header>
        <pj:MessageHeader pj:version="1.0" soap:mustUnderstand="1">
            <pj:From>
                <pj:PartyId pj:type="ABCDE">FUN</pj:PartyId>
            </pj:From>
            <pj:To>
                <pj:PartyId pj:type="ABCDE">PARTY</pj:PartyId>
            </pj:To>
            <pj:CPAId>uri:www.pjxml.org/socialService/Ping</pj:CPAId>
            <pj:ConversationId>FUN PARTY FUN 59c64t0087fg3kfs000003n9</pj:ConversationId>
            <pj:Service>uri:www.pjxml.org/socialService/</pj:Service>
            <pj:Action>Ping</pj:Action>
            <pj:MessageData>
                <pj:MessageId>FUN 59c64t0087fg3kfs000003n9</pj:MessageId>
                <pj:Timestamp>2013-10-22T17:12:20</pj:Timestamp>
            </pj:MessageData>
        </pj:MessageHeader>
        <pj:Via pj:id="59c64t0087fg3ki6000003na" pj:syncReply="False" pj:version="1.0"
                soap:actor="http://schemas.xmlsoap.org/soap/actor/next" soap:mustUnderstand="1">
            <pj:Service>uri:www.pjxml.org/socialService/</pj:Service>
            <pj:Action>Ping</pj:Action>
        </pj:Via>
        <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
            <ds:SignedInfo>
                <ds:CanonicalizationMethod
                        Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"></ds:CanonicalizationMethod>
                <ds:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"></ds:SignatureMethod>
                <ds:Reference URI="">
                    <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"></ds:DigestMethod>
                    <ds:DigestValue>9RXY9kp/Klx36gd4BULvST4qffI=</ds:DigestValue>
                </ds:Reference>
                <ds:Reference URI="../resources/attachment.xml">
                    <ds:Transforms>
                        <ds:Transform Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"></ds:Transform>
                    </ds:Transforms>
                    <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"></ds:DigestMethod>
                    <ds:DigestValue>3JcccO8+0bCUUR3EJxGJKJ+Wrbc=</ds:DigestValue>
                </ds:Reference>
            </ds:SignedInfo>
            <ds:SignatureValue>d0hBQLIvZ4fwUZlrsDLDZojvwK2DVaznrvSoA/JTjnS7XZ5oMplN9  THX4xzZap3+WhXwI2xMr3GKO................x7u+PQz1UepcbKY3BsO8jB3dxWN6r+F4qTyWa+xwOFxqLj546WX35f8zT4GLdiJI5oiYeo1YPLFFqTrwg==
            </ds:SignatureValue>
            <ds:KeyInfo>
                <ds:X509Data>
   <ds:X509Certificate>                MIIDjTCCAnWgAwIBAgIEeotzFjANBgkqhkiG9w0BAQsFADB3MQswCQYDVQQGEwJMSzEQMA4GA1UE...............qXfD/eY+XeIDyMQocRqTpcJIm8OneZ8vbMNQrxsRInxq+DsG+C92b
                    </ds:X509Certificate>
                </ds:X509Data>
                <ds:KeyValue>
                    <ds:RSAKeyValue>
                        <ds:Modulus>
                            k5y0amGgOQ2O/St0Kc2/xye80tX2fDEKs2YOlM/zCknL8VgK0CbAKVAwvJoycQL9mGRkPDmbitHe............StGofmsoKURzo8hofYEn41rGsq5wCuqJhhHYGDrPpFcuJiuI3SeXgcMtBnMwsIaKv2uHaPRbNX31WEuabuv6Q==
                        </ds:Modulus>
                        <ds:Exponent>AQAB</ds:Exponent>
                    </ds:RSAKeyValue>
                </ds:KeyValue>
            </ds:KeyInfo>
        </ds:Signature>
    </soap:Header>
    <soap:Body>
        <pr:GetPriceResponse xmlns:pr="http://www.pushpalankajaya.com/prices">
            <pr:Price>1.90</pr:Price>
        </pr:GetPriceResponse>
    </soap:Body>
</soap:Envelope>


In a next post we will see how to verify this signature, so that we can guarantee signed documents are not changed (in other words guarantee that the integrity of the content is preserved) .

Cheers!

6 comments :

  1. This comment has been removed by a blog administrator.

    ReplyDelete
  2. Hi,

    I was looking out for such example to digital sign a soap request to access a webservice. Thanks for the nice example.
    My query is webserver administrator has provided us a .Keystore file (probably a jks file). I would like to know whether privatekeyalias, privatekeypass and certificatealias values would be there in that keystore file or they are to be any values which we would like to set. What is command to see contain of .keystore. Please advise as this is the first time I am trying to sign an XML document.

    Regards

    Sudhir Kulkarni

    Mumbai - India

    ReplyDelete
    Replies
    1. Hi,

      The alias values are there in the keystore. But the keystore password, you should know from the administrator.

      Following command will list the certificates in the key store. If you know the alias you are looking at use the second command.

      keytool -list -v -keystore .jks

      keytool -list -v -keystore .jks -alias

      Delete
  3. Digital Signature in ASP.Net: Super Signature You can Download Supersignature Integration demo project
    electronic signature pad

    ReplyDelete
  4. Please check your sample. Ubuntuone is deleting the file on 31.7.2014 but it is already unavailable for visitors. Is it possible to attach it to your blog ?

    ReplyDelete
    Replies
    1. Thanks for the heads up.. I will updating the posts hosting them in a new location.

      Delete