C++

Extract SignatureValue from Signed XML

See more XML Digital Signatures Examples

Demonstrates how to extract the signature value from signed XML. C++

#include <CkStringBuilder.h>
#include <CkXml.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  This example will work with the following signed XML, which as been reformatted for readability.

    //  <?xml version="1.0" encoding="utf-8"?>
    //  <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
    //      <SOAP-ENV:Header>
    //          <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1">
    //              <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
    //                  <ds:SignedInfo>
    //                      <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#">
    //                          <InclusiveNamespaces xmlns="http://www.w3.org/2001/10/xml-exc-c14n#" PrefixList="wsse SOAP-ENV"/>
    //                      </ds:CanonicalizationMethod>
    //                      <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/>
    //                      <ds:Reference URI="#Body">
    //                          <ds:Transforms>
    //                              <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
    //                          </ds:Transforms>
    //                          <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
    //                          <ds:DigestValue>OwgHPZNfDkXnZsjpfzXqAcT3RV3HzmTsEy2bP44FJ0M=</ds:DigestValue>
    //                      </ds:Reference>
    //                  </ds:SignedInfo>
    //                  <ds:SignatureValue>C+7FWngU....DJFBcdg==</ds:SignatureValue>
    //                  <ds:KeyInfo>
    //                      <ds:KeyValue>
    //                          <ds:RSAKeyValue>
    //                              <ds:Modulus>sXeRhM55P13.....NAcibRw==</ds:Modulus>
    //                              <ds:Exponent>AQAB</ds:Exponent>
    //                          </ds:RSAKeyValue>
    //                      </ds:KeyValue>
    //                  </ds:KeyInfo>
    //              </ds:Signature>
    //          </wsse:Security>
    //      </SOAP-ENV:Header>
    //      <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
    //          <z:FooBar xmlns:z="http://example.com"/>
    //      </SOAP-ENV:Body>
    //  </SOAP-ENV:Envelope>

    //  -----------------------------------------------------------------------------------------
    //  There are a number of ways we can get the contents of the  <ds:SignatureValue>...</ds:SignatureValue>

    const char *filePath = "qa_data/xml_dsig_testing/sample_to_show_how_to_extract_sig.xml";

    //  If you know there will only be a single SignatureValue in the XML, you don't need to parse XML.
    //  Just do quick and simple string search..
    //  For example:
    CkStringBuilder sb;
    success = sb.LoadFile(filePath,"utf-8");
    if (success == false) {
        std::cout << "Failed to load file." << "\r\n";
        return;
    }

    const char *base64Sig = sb.getBetween("SignatureValue>","</");
    std::cout << "base64Sig = " << base64Sig << "\r\n";

    //  -----------------------------------------------------------------------------------------
    //  If the XML might contain multiple signatures, but the signatures will always be located in the 
    //  same place, then you can (beforehand) copy a sample signed XML into Chilkat's online tool
    //  at Generate Parsing Code from XML
    //  to get the path to the SignatureValue.  For example, the line of code generated for the SignatureValue
    //  for the above XML is:
    //  string ds_SignatureValue = xml.GetChildContent("SOAP-ENV:Header|wsse:Security|ds:Signature|ds:SignatureValue");

    //  So you can simply use that path..
    CkXml xml;
    success = xml.LoadXmlFile(filePath);
    //  Assume success..

    base64Sig = xml.getChildContent("SOAP-ENV:Header|wsse:Security|ds:Signature|ds:SignatureValue");
    std::cout << "base64Sig = " << base64Sig << "\r\n";

    //  -----------------------------------------------------------------------------------------
    //  Or perhaps you don't know where the signature is located in the XML.
    //  You can search for the tag..
    CkXml *xSigVal = xml.SearchForTag(xml,"*:SignatureValue");
    if (xml.get_LastMethodSuccess() == true) {
        std::cout << "base64Sig = " << xSigVal->content() << "\r\n";
        delete xSigVal;
    }
    else {
        std::cout << "No SignatureValue found." << "\r\n";
    }
    }