(Lianja) Create XML Digital Signature using Certificate on Smart Card

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Demonstrates how to load a certificate located on a smart card or USB token and then use it for creating an XML digital signature such that the cryptographic signing happens on the smart card.

Note: This functionality was introduced in Chilkat v9.5.0.87.

Note: The ScMinidriver functionality is for Windows-only because ScMinidriver DLLs only exist on Windows. In the next version, Chilkat will be releasing a Pkcs11 class to support Linux, MacOSX, and possibly other operating systems.

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

loScmd = createobject("CkScMinidriver")

// Reader names (smart card readers or USB tokens) can be discovered
// via List Readers or Find Smart Cards
lcReaderName = "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0"
llSuccess = loScmd.AcquireContext(lcReaderName)
if (llSuccess = .F.) then
    ? loScmd.LastErrorText
    release loScmd
    return
endif

// If successful, the name of the currently inserted smart card is available:
? "Card name: " + loScmd.CardName

// If desired, perform regular PIN authentication with the smartcard.
// For more details about smart card PIN authentication, see the Smart Card PIN Authentication Example
lnRetval = loScmd.PinAuthenticate("user","000000")
if (lnRetval <> 0) then
    ? "PIN Authentication failed."
endif

// You can find a cerficate using any of the following certificate parts:
// "subjectDN" -- The full distinguished name of the cert.
// "subjectDN_withTags" -- Same as above, but in a format that includes the subject part tags, such as the "CN=" in "CN=something"
// "subjectCN" -- The common name part (CN) of the certificate's subject.
// "serial" -- The certificate serial number.
// "serial:issuerCN" -- The certificate serial number + the issuer's common name, delimited with a colon char.
// These are the same certificate parts that can be retrieved by listing certificates on the smart card (or USB token).
// See List Certificates on Smart Card Example
lcCertPart = "subjectCN"
lcPartValue = "PIVKey E42D60A759D39147A26E0AF2FB1183C5"

// If the certificate is found, it is loaded into the cert object.
loCert = createobject("CkCert")
llSuccess = loScmd.FindCert(lcCertPart,lcPartValue,loCert)
if (llSuccess = .F.) then
    ? "Failed to find the certificate."
    loScmd.DeleteContext()
    release loScmd
    release loCert
    return
endif

? "Successfully loaded the cert object from the smart card / USB token."

// Note: When successful, the cert object is internally linked to the ScMinidriver object's authenticated session.
// The cert object can now be used to sign or do other cryptographic operations that occur on the smart card / USB token.
// If your application calls PinDeauthenticate or DeleteContext, the cert will no longer be able to sign on the smart card
// because the smart card ScMinidriver session will no longer be authenticated or deleted.

// ------------------------------------------------------------------------------------------------------------
// We have the certificate.  Now let's do the XML digital signature..

// Create the following XML to be signed:

// <?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>

loXml = createobject("CkXml")
loXml.Tag = "SOAP-ENV:Envelope"
loXml.AddAttribute("xmlns:SOAP-ENV","http://schemas.xmlsoap.org/soap/envelope/")
loXml.UpdateAttrAt("SOAP-ENV:Header|wsse:Security",.T.,"xmlns:wsse","http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd")
loXml.UpdateAttrAt("SOAP-ENV:Header|wsse:Security",.T.,"SOAP-ENV:mustUnderstand","1")
loXml.UpdateAttrAt("SOAP-ENV:Body",.T.,"xmlns:SOAP-SEC","http://schemas.xmlsoap.org/soap/security/2000-12")
loXml.UpdateAttrAt("SOAP-ENV:Body",.T.,"SOAP-SEC:id","Body")
loXml.UpdateAttrAt("SOAP-ENV:Body|z:FooBar",.T.,"xmlns:z","http://example.com")

// Prepare for signing...
loGen = createobject("CkXmlDSigGen")

// Indicate where the Signature will be inserted.
loGen.SigLocation = "SOAP-ENV:Envelope|SOAP-ENV:Header|wsse:Security"

// Add a reference to the fragment of the XML to be signed.

// Note: "Body" refers to the XML element having an "id" equal to "Body", where "id" is case insensitive
// and where any namespace might qualify the attribute.  In this case, the SOAP-ENV:Body fragment is signed
// NOT because the tag = "Body", but because it has SOAP-SEC:id="Body"
loGen.AddSameDocRef("Body","sha1","EXCL_C14N","","")

// (You can read about the SignedInfoPrefixList in the online reference documentation.  It's optional..)
loGen.SignedInfoPrefixList = "wsse SOAP-ENV"

// Provide the private key for signing via the certificate, and indicate that
// we want the base64 of the certificate embedded in the KeyInfo.
loGen.KeyInfoType = "X509Data"
loGen.X509Type = "Certificate"

// Note: Our certificate was loaded from the smartcard and is internally linked to the authenticated ScMinidriver session.
// The signing will occur on the smart card using the chosen certificate.
llBUsePrivateKey = .T.
llSuccess = loGen.SetX509Cert(loCert,llBUsePrivateKey)
if (llSuccess <> .T.) then
    ? loGen.LastErrorText
    release loScmd
    release loCert
    release loXml
    release loGen
    return
endif

// Everything's specified.  Now create and insert the Signature
loSbXml = createobject("CkStringBuilder")
loXml.GetXmlSb(loSbXml)
llSuccess = loGen.CreateXmlDSigSb(loSbXml)
if (llSuccess <> .T.) then
    ? loGen.LastErrorText
    release loScmd
    release loCert
    release loXml
    release loGen
    release loSbXml
    return
endif

// Examine the XML with the digital signature inserted
? loSbXml.GetAsString()

// ------------------------------------------------------------------------------------------------------------
// Cleanup our ScMinidriver session...

// When finished with operations that required authentication, you may if you wish, deauthenticate the session.
llSuccess = loScmd.PinDeauthenticate("user")
if (llSuccess = .F.) then
    ? loScmd.LastErrorText
endif

// Delete the context when finished with the card.
llSuccess = loScmd.DeleteContext()
if (llSuccess = .F.) then
    ? loScmd.LastErrorText
endif



release loScmd
release loCert
release loXml
release loGen
release loSbXml