Zig

Create XML Signature with External Data Reference

See more XML Digital Signatures Examples

Demonstrates how to create an XML digital signature where the data is external. In this case, the data is a JPG file.

This example requires Chilkat v9.5.0.69 or greater.

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.

    // This example inserts an XML signature in the following XML:

    // <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    // <abc>
    //   <xyz>
    //     <jpg>
    //         <name>starfish.jpg</name>
    //         <url>https://www.chilkatsoft.com/images/starfish.jpg</url>
    //     </jpg>
    //   </xyz>
    // </abc>

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

    const url = "https://www.chilkatsoft.com/exampleData/addSignatureToThis.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;
    };

    // We'll use an RSA private key for signing.
    const rsa_key = try chilkat.PrivateKey.init();
    defer rsa_key.deinit();
    rsa_key.loadPemFile("qa_data/rsa/rsaPrivKey_pkcs8.pem") catch {
        std.debug.print("{s}\n", .{try rsa_key.getLastErrorText(alloc)});
        return;
    };

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

    // Indicate were the Signature will be inserted:
    xml_sig_gen.setSigLocation("abc|xyz|jpg");

    // Provide the RSA key to be used for signing:
    xml_sig_gen.setPrivateKey(rsa_key) catch {};

    // Fetch the JPG image data.
    const jpg_url = "https://www.chilkatsoft.com/images/starfish.jpg";
    const jpg_data = try chilkat.BinData.init();
    defer jpg_data.deinit();
    http.quickGetBd(jpg_url, jpg_data) catch {
        std.debug.print("{s}\n", .{try http.getLastErrorText(alloc)});
        return;
    };

    // Add the external data reference:
    xml_sig_gen.addExternalBinaryRef(jpg_url, jpg_data, "sha256", "") catch {};

    // Create the XML digital signature:
    xml_sig_gen.createXmlDSigSb(sb_xml) catch {
        std.debug.print("{s}\n", .{try xml_sig_gen.getLastErrorText(alloc)});
        return;
    };

    // Examine the XML that now contains the Signature:
    std.debug.print("{s}\n", .{try sb_xml.getAsString(alloc)});

    // <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    // <abc>
    //   <xyz>
    //     <jpg>
    //         <name>starfish.jpg</name>
    //         <url>https://www.chilkatsoft.com/images/starfish.jpg</url>
    //     <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#rsa-sha256"/><ds:Reference URI="https://www.chilkatsoft.com/images/starfish.jpg"><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>AOU810yJV5Np/DnO29qpObqiTSTTCDvxGsX5ayiTYXI=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>ApHRr6nilNrzt3dLveC9zlPoSllaCMfHsbAwr+vYBPkHkJ4wD5LzDDhi1tSJZAAeTckmvSqIG3Wi0rgXQiSM644MD3coBFx4QgrY+GZ+XJJE2Y0Ye3VvaQBiRdUW3INGsW4GLubncgQk5JhuAQjo6O/GKpfEuYqUJj/6CLHLQwMPwbZ2043ykgzuPFoOZf6EydJMBAn1ORMvrpUn+zuA9UngOTGap6eWE4CeiNx23BRC2wSztbUjdCLcqXvgiYu/v0tBNaTcwy7b6+IFtwv/lNUUBUQJ/3p+aErzFn3wLeH3yeqpDCU0U6Dqu5SS1jYupcWWsLHJjYnj2066DPJi/g==</ds:SignatureValue><ds:KeyInfo><ds:KeyValue><ds:RSAKeyValue><ds:Modulus>sXeRhM55P13FbpNcXAMR3olbw2Wa6keZIHu5YTZYUBTlYWId+pNiwUz3zFIEo+0IfYR0H27ybIycQO+1IIzJofUFNMAL3tZps2OKPlsjuCPls6kXpXhv/gvhux8LrCtp4PcKWqJ6QVOZKChc7WAx40qFWzHi57ueqRTv3x0kESqGg/VjsqyTEvb55psJO2RsfhLT7+YVh3hImRM3RDaJdkTkPuOxeFyT6N7VXD09329sLuS3QkUbE9zEKDnz9X3d8dEQdJhSI9ba5fxl8R7fu8pB67ElfzFml96X1jLFtzy1pzOT5Fc4ROcaqlYckVzdBq9sxezm6MYmDBjNAcibRw==</ds:Modulus><ds:Exponent>AQAB</ds:Exponent></ds:RSAKeyValue></ds:KeyValue></ds:KeyInfo></ds:Signature></jpg>
    //   </xyz>
    // </abc>
    //
}