Dart

SOAP XML Digital Signature using RSA Key

See more XML Digital Signatures Examples

Demonstrates how to sign content in a SOAP XML document using an RSA key.

This example requires Chilkat v9.5.0.69 or greater.

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // The SOAP XML to be signed in this example contains the following:

  // <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
  // <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"></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>
  // 

  // The above XML is available at https://www.chilkatsoft.com/exampleData/soapToSign.xml
  // Fetch the XML and then sign it..

  final url = 'https://www.chilkatsoft.com/exampleData/soapToSign.xml';
  final http = CkHttp();
  final sbSoapXml = CkStringBuilder();
  try {
    http.quickGetSb(url, sbSoapXml);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // We'll need an RSA private key for signing.  
  // There are many ways of getting an RSA private key using Chilkat.  This example
  // will load one from a PEM file.
  final rsaKey = CkPrivateKey();
  try {
    rsaKey.loadPemFile('qa_data/rsa/rsaPrivKey_pkcs8.pem');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // To create the XML digital signature (i.e. embed the signature within
  // the SOAP XML), we specify what is desired, and then call the method to 
  // create the XML signature.
  // 
  // For example, the application must provide the following:
  //     - Where to put the signature.
  //     - What to sign.
  //     - The algorithms to be used.
  //     - The key to be used for signing.
  // 

  final xmlSigGen = CkXmlDSigGen();

  // In this example, we're going to put the signature within the wsse:Security element.
  // To specify the location, set the SigLocation property to the XML path to this element,
  // using vertical bar characters to separate tags.
  xmlSigGen.sigLocation = 'SOAP-ENV:Envelope|SOAP-ENV:Header|wsse:Security';

  // An XML digital signature contains one or more references.  These are references to the parts
  // of the XML document to be signed (a same document reference), or can be external references.
  // This example will add a single same-document reference.  We'll add a reference to the XML fragment
  // at SOAP-ENV:Body, which is indicated by providing the value of the "ID" attribute (where "ID" is case
  // insensitive).  For each same-document reference, we must also indicate the hash algorithm and XML canonicalization
  // algorithm to be used.  For this example we'll choose SHA-256 and Exclusive XML Canonicalization.
  xmlSigGen.addSameDocRef('Body', 'sha256', 'EXCL_C14N', '', '');

  // Let's provide the RSA key to be used for signing:
  xmlSigGen.setPrivateKey(rsaKey);

  // We're leaving the following properties at their default values:
  // 
  //    - SigNamespacePrefix (default is "ds")
  //    - SigningAlg (for RSA keys. The default is PKCS1-v1_5, can be changed to RSASSA-PSS.)
  //    - SignedInfoCanonAlg  (default is EXCL_C14N)
  //    - SignedInfoDigestMethod (default is sha256)
  //    - KeyInfoType (default is "KeyValue", where the RSA public key is included in the Signature)

  // Note: Each Reference has it's own specified algorithms for XML canonicalization and hashing,
  // and the actual signature part (the SignedInfo) has it's own algorithms for the same.
  // They may or may not be the same.  In this example, we use Exclusive XML Canonicalization and SHA-256 throughout.

  // Finally, we're going to set one property that's optional, but commonly used.
  // It's the SignedInfoPrefixList.  In this case, we're using Exclusive Canonicalization, and the signature
  // will be placed in a location within the XML document where namespace prefixes are used in the ancestors.
  // Specifically, the "wsse" and "SOAP-ENV" namespace prefixes are used.
  xmlSigGen.signedInfoPrefixList = 'wsse SOAP-ENV';

  // OK, everything's specified, so let's create the XML digital signature:
  // This in-place signs the XML.  If successful, sbSoapXml will contain the 
  // XML with the digital signature at the specified location.
  try {
    xmlSigGen.createXmlDSigSb(sbSoapXml);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Examine the signed SOAP XML:
  print(sbSoapXml.getAsString());

  // This is the signed SOAP XML.
  // Chilkat emits the Signature in compact form on a single line.  Whitespace in XML signatures
  // matters.  Chilkat's opinion is that writing the Signature without whitespace minimizes the chance
  // for problems with whatever software might be verifying the signature.

  // <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
  // <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+7FWngUpJ33Q1yq8uuscjCyPN2IO4cJhpMv03Jrrht1V+4gvJQLIBk6HHjo1uPQyfYj6zji3pg+fOyGUptp17CsRvjCzSpP35vB2lEzHeS8dcY8XfrEtTP/0FNn75LmhhkOPy0wjWkgDVbgzhXpEk9az8r8fQVTM3vrcmXT+WdMWJXKBRFt6PLAhsFt0scOFTWAkLGyCwygzimDKX2nT63TOit9BigtIx7fPRuMkbybMKCGGABq2DiEbvrPOiN3SUYpyMNR9KehRAGN+OWnESaDC6DhOvbKR88XHkM+GeaRe9PWdrRHrwGfp3qgolKjR/wFRSa1YGSBKAhDJFBcdg==</ds:SignatureValue><ds:KeyInfo><ds:KeyValue><ds:RSAKeyValue><ds:Modulus>sXeRhM55P13FbpNcXAMR3olbw2Wa6keZIHu5YTZYUBTlYWId+pNiwUz3zFIEo+0IfYR0H27ybIycQO+1IIzJofUFNMAL3tZps2OKPlsjuCPls6kXpXhv/gvhux8LrCtp4PcKWqJ6QVOZKChc7WAx40qFWzHi57ueqRTv3x0kESqGg/VjsqyTEvb55psJO2RsfhLT7+YVh3hImRM3RDaJdkTkPuOxeFyT6N7VXD09329sLuS3QkUbE9zEKDnz9X3d8dEQdJhSI9ba5fxl8R7fu8pB67ElfzFml96X1jLFtzy1pzOT5Fc4ROcaqlYckVzdBq9sxezm6MYmDBjNAcibRw==</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>

  // Here's the signature part formatted for easier reading.
  // (Adding whitespace to the SignedInfo breaks the signature, so you wouldn't want to do this..)

  //     <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+7FWngUp....BKAhDJFBcdg==</ds:SignatureValue>
  //         <ds:KeyInfo>
  //             <ds:KeyValue>
  //                 <ds:RSAKeyValue>
  //                     <ds:Modulus>sXeRhM55P13FbpNcXAMR....MYmDBjNAcibRw==</ds:Modulus>
  //                     <ds:Exponent>AQAB</ds:Exponent>
  //                 </ds:RSAKeyValue>
  //             </ds:KeyValue>
  //         </ds:KeyInfo>
  //     </ds:Signature>
}