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Visual FoxPro

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.

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LOCAL lnSuccess
LOCAL lcUrl
LOCAL loHttp
LOCAL loSbSoapXml
LOCAL loEcKey
LOCAL loXmlSigGen
LOCAL loVerifier
LOCAL lnBVerified

lnSuccess = 0

* 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..

lcUrl = "https://www.chilkatsoft.com/exampleData/soapToSign.xml"
loHttp = CreateObject('Chilkat.Http')
loSbSoapXml = CreateObject('Chilkat.StringBuilder')
lnSuccess = loHttp.QuickGetSb(lcUrl,loSbSoapXml)
IF (lnSuccess <> 1) THEN
    ? loHttp.LastErrorText
    RELEASE loHttp
    RELEASE loSbSoapXml
    CANCEL
ENDIF

* 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
loEcKey = CreateObject('Chilkat.PrivateKey')
lnSuccess = loEcKey.LoadPemFile("qa_data/ecc/secp256r1-key.pem")
IF (lnSuccess <> 1) THEN
    ? loEcKey.LastErrorText
    RELEASE loHttp
    RELEASE loSbSoapXml
    RELEASE loEcKey
    CANCEL
ENDIF

* 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.
* 

loXmlSigGen = CreateObject('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.
loXmlSigGen.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.
loXmlSigGen.AddSameDocRef("Body","sha256","EXCL_C14N","","")

* Let's provide the ECDSA key to be used for signing:
loXmlSigGen.SetPrivateKey(loEcKey)

* 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.
loXmlSigGen.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.
lnSuccess = loXmlSigGen.CreateXmlDSigSb(loSbSoapXml)
IF (lnSuccess <> 1) THEN
    ? loXmlSigGen.LastErrorText
    RELEASE loHttp
    RELEASE loSbSoapXml
    RELEASE loEcKey
    RELEASE loXmlSigGen
    CANCEL
ENDIF

* Examine the signed SOAP XML:
? loSbSoapXml.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:

loVerifier = CreateObject('Chilkat.XmlDSig')

* First load the XML containing the signature(s) to be verified.
lnSuccess = loVerifier.LoadSignatureSb(loSbSoapXml)
IF (lnSuccess <> 1) THEN
    ? loVerifier.LastErrorText
    RELEASE loHttp
    RELEASE loSbSoapXml
    RELEASE loEcKey
    RELEASE loXmlSigGen
    RELEASE loVerifier
    CANCEL
ENDIF

lnBVerified = loVerifier.VerifySignature(1)
IF (lnBVerified <> 1) THEN
    ? loVerifier.LastErrorText
ENDIF

? "Signature verified = " + STR(lnBVerified)

RELEASE loHttp
RELEASE loSbSoapXml
RELEASE loEcKey
RELEASE loXmlSigGen
RELEASE loVerifier