(Go) PKCS11 XML Signature using Certificate and Private Key on Smart Card / USB Token

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Sample code showing how to use PKCS11 to create an XML digital signature with a certificate and private key stored on a smart card or USB token.

Note: This example requires Chilkat v9.5.0.96 or later.

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

    // Note: Chilkat's PKCS11 implementation runs on Windows, Linux, Mac OS X, and other supported operating systems.

    pkcs11 := chilkat.NewPkcs11()

    // This example is tested on Windows using a Giesecke and Devrient Sm@rtCafe Expert 3.2 smart card.
    // You will use the DLL (or shared lib) provided by your smart card vendor, or a DLL compatible with your smart card.
    // On Windows, if the DLL is located in C:\Windows\System32, specify only the filename.
    // Otherwise provide the full path.
    pkcs11.SetSharedLibPath("aetpkss1.dll")

    // Make it an authenticated session by calling Login.
    userType := 1
    // Make sure to use the correct PIN for your smart card..
    pin := "0000"

    success := pkcs11.QuickSession(userType,pin)
    if success == false {
        fmt.Println(pkcs11.LastErrorText())
        pkcs11.DisposePkcs11()
        return
    }

    // Get the certificate (on the smart card) that has a private key.
    cert := chilkat.NewCert()
    success = pkcs11.FindCert("privateKey","",cert)
    if success == true {
        fmt.Println("Cert with private key: ", cert.SubjectCN())
    } else {
        fmt.Println("No certificates having a private key were found.")
        success = pkcs11.CloseSession()
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        return
    }

    // --------------------------------------------------------------------------
    // At this point, we have the cert to be used for signing.
    // Our XML signing code is the same as for a cert obtained from any other source..

    // First generate the following XML to be signed:
    // Use this online tool to generate code from sample XML: 
    // Generate Code to Create XML

    // <?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>

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

    gen := chilkat.NewXmlDSigGen()

    // Indicate where the Signature will be inserted.
    gen.SetSigLocation("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"
    gen.AddSameDocRef("Body","sha1","EXCL_C14N","","")

    // (You can read about the SignedInfoPrefixList in the online reference documentation.  It's optional..)
    gen.SetSignedInfoPrefixList("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.
    gen.SetKeyInfoType("X509Data")
    gen.SetX509Type("Certificate")

    bUsePrivateKey := true
    success = gen.SetX509Cert(cert,bUsePrivateKey)
    if success != true {
        fmt.Println(gen.LastErrorText())
        success = pkcs11.CloseSession()
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        xml.DisposeXml()
        gen.DisposeXmlDSigGen()
        return
    }

    // Everything's specified.  Now create and insert the Signature
    sbXml := chilkat.NewStringBuilder()
    xml.SetEmitCompact(true)
    xml.GetXmlSb(sbXml)

    success = gen.CreateXmlDSigSb(sbXml)
    if success != true {
        fmt.Println(gen.LastErrorText())
        success = pkcs11.CloseSession()
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        xml.DisposeXml()
        gen.DisposeXmlDSigGen()
        sbXml.DisposeStringBuilder()
        return
    }

    // Examine the XML with the digital signature inserted
    fmt.Println(*sbXml.GetAsString())

    // --------------------------------------------------------------------------

    // Revert to an unauthenticated session by calling Logout.
    success = pkcs11.Logout()
    if success == false {
        fmt.Println(pkcs11.LastErrorText())
        success = pkcs11.CloseSession()
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        xml.DisposeXml()
        gen.DisposeXmlDSigGen()
        sbXml.DisposeStringBuilder()
        return
    }

    // When finished, close the session.
    // It is important to close the session (memory leaks will occur if the session is not properly closed).
    success = pkcs11.CloseSession()
    if success == false {
        fmt.Println(pkcs11.LastErrorText())
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        xml.DisposeXml()
        gen.DisposeXmlDSigGen()
        sbXml.DisposeStringBuilder()
        return
    }

    fmt.Println("Success.")

    pkcs11.DisposePkcs11()
    cert.DisposeCert()
    xml.DisposeXml()
    gen.DisposeXmlDSigGen()
    sbXml.DisposeStringBuilder()