Zig

Create XML Digital Signature using Certificate on Smart Card

See more ScMinidriver Examples

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. Zig

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.

    const scmd = try chilkat.ScMinidriver.init();
    defer scmd.deinit();

    // Reader names (smart card readers or USB tokens) can be discovered
    // via List Readers or Find Smart Cards
    const reader_name = "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0";
    scmd.acquireContext(reader_name) catch {
        std.debug.print("{s}\n", .{try scmd.getLastErrorText(alloc)});
        return;
    };

    // If successful, the name of the currently inserted smart card is available:
    std.debug.print("Card name: {s}\n", .{try scmd.getCardName(alloc)});

    // If desired, perform regular PIN authentication with the smartcard.
    // For more details about smart card PIN authentication, see the Smart Card PIN Authentication Example
    const retval = scmd.pinAuthenticate("user", "000000");
    if (retval != 0) {
        std.debug.print("PIN Authentication failed.\n", .{});
    }

    // 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
    const cert_part = "subjectCN";
    const part_value = "PIVKey E42D60A759D39147A26E0AF2FB1183C5";

    // If the certificate is found, it is loaded into the cert object.
    const cert = try chilkat.Cert.init();
    defer cert.deinit();
    scmd.findCert(cert_part, part_value, cert) catch {
        std.debug.print("Failed to find the certificate.\n", .{});
        scmd.deleteContext() catch {};
        return;
    };

    std.debug.print("Successfully loaded the cert object from the smart card / USB token.\n", .{});

    // 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>

    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 {};

    // Prepare for signing...
    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");

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

    // Everything's specified.  Now create and insert the Signature
    const sb_xml = try chilkat.StringBuilder.init();
    defer sb_xml.deinit();
    xml.getXmlSb(sb_xml) catch {};
    gen.createXmlDSigSb(sb_xml) catch {
        std.debug.print("{s}\n", .{try gen.getLastErrorText(alloc)});
        return;
    };

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

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

    // When finished with operations that required authentication, you may if you wish, deauthenticate the session.
    scmd.pinDeauthenticate("user") catch {
        std.debug.print("{s}\n", .{try scmd.getLastErrorText(alloc)});
    };

    // Delete the context when finished with the card.
    scmd.deleteContext() catch {
        std.debug.print("{s}\n", .{try scmd.getLastErrorText(alloc)});
    };
}