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

See more PKCS11 Examples

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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const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    // 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.

    const pkcs11 = try chilkat.Pkcs11.init();
    defer pkcs11.deinit();

    // 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.
    const user_type = 1;
    // Make sure to use the correct PIN for your smart card..
    const pin = "0000";

    pkcs11.quickSession(user_type, pin) catch {
        std.debug.print("{s}\n", .{try pkcs11.getLastErrorText(alloc)});
        return;
    };

    // Get the certificate (on the smart card) that has a private key.
    const cert = try chilkat.Cert.init();
    defer cert.deinit();
    if (pkcs11.findCert("privateKey", "", cert)) {
        std.debug.print("Cert with private key: {s}\n", .{try cert.getSubjectCN(alloc)});
    } else |_| {
        std.debug.print("No certificates having a private key were found.\n", .{});
        try pkcs11.closeSession();
        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>

    const xml = try chilkat.Xml.init();
    defer xml.deinit();
    xml.setTag("SOAP-ENV:Envelope");
    xml.addAttribute("xmlns:SOAP-ENV", "http://schemas.xmlsoap.org/soap/envelope/") catch {};
    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") catch {};
    xml.updateAttrAt("SOAP-ENV:Header|wsse:Security", true, "SOAP-ENV:mustUnderstand", "1") catch {};
    xml.updateAttrAt("SOAP-ENV:Body", true, "xmlns:SOAP-SEC", "http://schemas.xmlsoap.org/soap/security/2000-12") catch {};
    xml.updateAttrAt("SOAP-ENV:Body", true, "SOAP-SEC:id", "Body") catch {};
    xml.updateAttrAt("SOAP-ENV:Body|z:FooBar", true, "xmlns:z", "http://example.com") catch {};

    const gen = try chilkat.XmlDSigGen.init();
    defer gen.deinit();

    // 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", "", "") catch {};

    // (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");

    const b_use_private_key = true;
    gen.setX509Cert(cert, b_use_private_key) catch {
        std.debug.print("{s}\n", .{try gen.getLastErrorText(alloc)});
        try pkcs11.closeSession();
        return;
    };

    // Everything's specified.  Now create and insert the Signature
    const sb_xml = try chilkat.StringBuilder.init();
    defer sb_xml.deinit();
    xml.setEmitCompact(true);
    xml.getXmlSb(sb_xml) catch {};

    gen.createXmlDSigSb(sb_xml) catch {
        std.debug.print("{s}\n", .{try gen.getLastErrorText(alloc)});
        try pkcs11.closeSession();
        return;
    };

    // Examine the XML with the digital signature inserted
    std.debug.print("{s}\n", .{try sb_xml.getAsString(alloc)});

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

    // Revert to an unauthenticated session by calling Logout.
    pkcs11.logout() catch {
        std.debug.print("{s}\n", .{try pkcs11.getLastErrorText(alloc)});
        try pkcs11.closeSession();
        return;
    };

    // When finished, close the session.
    // It is important to close the session (memory leaks will occur if the session is not properly closed).
    pkcs11.closeSession() catch {
        std.debug.print("{s}\n", .{try pkcs11.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("Success.\n", .{});
}