Zig

Verify HMAC XML Digital Signature

See more XML Digital Signatures Examples

Demonstrates how to validate an XML digital signature signed with an HMAC key. 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.

    // The XML containing the Signature to be verified contains the following:

    // <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    // <collection Id="root">
    //     <album>
    //         <title>Questions, unanswered</title>
    //         <artist>Steve and the flubberblubs</artist>
    //         <year>1989</year>
    //         <t:tracks xmlns:t="http://test.xades4j/tracks">
    //             <t:song length="4:05" tracknumber="1">
    //                 <t:title>What do you know?</t:title>
    //                 <t:artist>Steve and the flubberblubs</t:artist>
    //                 <t:lastplayed>2006-10-17-08:31</t:lastplayed>
    //             </t:song>
    //             <t:song length="3:45" tracknumber="2">
    //                 <t:title>Who do you know?</t:title>
    //                 <t:artist>Steve and the flubberblubs</t:artist>
    //                 <t:lastplayed>2006-10-17-08:35</t:lastplayed>
    //             </t:song>
    //             <t:song length="5:14" tracknumber="3">
    //                 <t:title>When do you know?</t:title>
    //                 <t:artist>Steve and the flubberblubs</t:artist>
    //                 <t:lastplayed>2006-10-17-08:39</t:lastplayed>
    //             </t:song>
    //             <t:song length="4:19" tracknumber="4">
    //                 <t:title>Do you know?</t:title>
    //                 <t:artist>Steve and the flubberblubs</t:artist>
    //                 <t:lastplayed>2006-10-17-08:44</t:lastplayed>
    //             </t:song>
    //         </t:tracks>
    //     </album>
    // <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#"/><ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#hmac-sha256"/><ds:Reference URI="#root"><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>rD/g8soqKz8EiPUBhEWfcQacS0ta4ULHX3dKMEH6ZoQ=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>R8dXP95VRYJBfL6d0Peogybdk27+R+JIfX8jnVu0NOI=</ds:SignatureValue></ds:Signature></collection>

    // The above XML is available at https://www.chilkatsoft.com/exampleData/hmacSigned.xml
    // First fetch the XML..

    const url = "https://www.chilkatsoft.com/exampleData/hmacSigned.xml";
    const http = try chilkat.Http.init();
    defer http.deinit();
    const sb_xml = try chilkat.StringBuilder.init();
    defer sb_xml.deinit();
    http.quickGetSb(url, sb_xml) catch {
        std.debug.print("{s}\n", .{try http.getLastErrorText(alloc)});
        return;
    };

    const verifier = try chilkat.XmlDSig.init();
    defer verifier.deinit();

    // Load the XML containing the signature to be verified.
    verifier.loadSignatureSb(sb_xml) catch {
        std.debug.print("{s}\n", .{try verifier.getLastErrorText(alloc)});
        return;
    };

    // Provide the HMAC key
    // The HMAC key for this signature is the us-ascii bytes of the string "secret",
    // It can be set in any of the following ways (and also more ways not shown here..)
    verifier.setHmacKey("secret", "ascii") catch {};
    // or
    verifier.setHmacKey("c2VjcmV0", "base64") catch {};
    // or
    verifier.setHmacKey("736563726574", "hex") catch {};

    // Verify the signature
    const b_verified = if (verifier.verifySignature(true)) true else |_| false;
    std.debug.print("Signature verified = {}\n", .{b_verified});
}