C#

Create XML Digital Signature using a ECDSA Key

See more XML Digital Signatures Examples

Demonstrates how to create an XML digital signature using a ECDSA key.

This example requires Chilkat v9.5.0.69 or greater.

C#

bool success = false;

//  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..

string url = "https://www.chilkatsoft.com/exampleData/soapToSign.xml";
Chilkat.Http http = new Chilkat.Http();
Chilkat.StringBuilder sbSoapXml = new Chilkat.StringBuilder();
success = http.QuickGetSb(url,sbSoapXml);
if (success != true) {
    Debug.WriteLine(http.LastErrorText);
    return;
}

//  This example uses an ECDSA private key for signing.  
//  There are many ways to load an ECDSA private key using Chilkat.  This example
//  will load from an unencrypted PEM file.

//  For your convenience, Chilkat put this sample ECDSA PEM here:  https://www.chilkatsoft.com/exampleData/secp256r1-key.zip
Chilkat.PrivateKey ecKey = new Chilkat.PrivateKey();
success = ecKey.LoadPemFile("qa_data/ecc/secp256r1-key.pem");
if (success != true) {
    Debug.WriteLine(ecKey.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.
//  

Chilkat.XmlDSigGen xmlSigGen = new Chilkat.XmlDSigGen();

//  In this example, the Signature will be placed 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.  A given reference
//  can be a same-document reference (to an XML fragment), or an external reference.
//  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 ECDSA key to be used for signing:
xmlSigGen.SetPrivateKey(ecKey);

//  We're leaving the following properties at their default values:
//  
//     - SigNamespacePrefix (default is "ds")
//     - SignedInfoCanonAlg  (default is EXCL_C14N)
//     - SignedInfoDigestMethod (default is sha256)
//     - KeyInfoType (default is "KeyValue", where the ECDSA public key is included in the Signature)

//  Note: Each Reference specifies its own algorithms for XML canonicalization and hashing.
//  The SignedInfo part also has specified hash and canonicalization algorithms, which may be different
//  than the algorithms used in the References.
//  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.
success = xmlSigGen.CreateXmlDSigSb(sbSoapXml);
if (success != true) {
    Debug.WriteLine(xmlSigGen.LastErrorText);
    return;
}

//  Examine the signed SOAP XML:
Debug.WriteLine(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#ecdsa-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>jmPSGgtirHSjjcs/o0NIDwwvy4aFBCEosSN+XP5NLVuGpRYnS2EM7mItiw6TKmESAoJYV23ZN4pZ9BFRKSvZqw==</ds:SignatureValue><ds:KeyInfo><ds:KeyValue><ds:ECKeyValue xmlns="http://www.w3.org/2009/xmldsig11#"><ds:NamedCurve URI="urn:oid:1.2.840.10045.3.1.7" /><ds:PublicKey>BOVKaiLPKEDChhkA64UEBOXTv/VFHnhrUPN+bXqCvEl7rroAYpH5tKzbiGTtMSlp4JO9Pxg44zeX7EoWDvOrpD0=</ds:PublicKey></ds:ECKeyValue></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>

//  The above signed XML contains the ECDSA public key in the ECKeyValue fragment (within the ds:KeyInfo).
//  The signature can easily be verified like this:

Chilkat.XmlDSig verifier = new Chilkat.XmlDSig();

//  First load the XML containing the signature(s) to be verified.
success = verifier.LoadSignatureSb(sbSoapXml);
if (success != true) {
    Debug.WriteLine(verifier.LastErrorText);
    return;
}

bool bVerified = verifier.VerifySignature(true);
if (bVerified != true) {
    Debug.WriteLine(verifier.LastErrorText);
}

Debug.WriteLine("Signature verified = " + Convert.ToString(bVerified));