Zig

Create PEM-encoded PKCS#7 Detached Signature

See more Digital Signatures Examples

Demonstrates how to create a PKCS7 PEM-encoded object containing a detached signature. 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 cert = try chilkat.Cert.init();
    defer cert.deinit();

    // Load the cert and private key.
    cert.loadPfxFile("qa_data/pfx/myCertAndKey.p12", "password") catch {
        std.debug.print("{s}\n", .{try cert.getLastErrorText(alloc)});
        return;
    };

    const crypt = try chilkat.Crypt2.init();
    defer crypt.deinit();

    crypt.setSigningCert(cert) catch {
        std.debug.print("{s}\n", .{try crypt.getLastErrorText(alloc)});
        return;
    };

    // Use SHA-256
    crypt.setHashAlgorithm("sha256");

    // Hash the utf-8 byte representation of the string
    crypt.setCharset("utf-8");

    // Return the result in base64
    crypt.setEncodingMode("base64Mime");

    // Sign some text to create a detached signature (i.e. a signature that does not include the signed data)
    const text_to_sign = "This is the text to be hashed and signed.";
    const sig_base64 = crypt.signStringENC(alloc, text_to_sign) catch {
        std.debug.print("{s}\n", .{try crypt.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("{s}\n", .{sig_base64});

    // The result:

    // MIIWbgYJKoZIhvcNAQcCoIIWXzCCFlsCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
    // ghMXMIIFuzCCA6OgAwIBAgIIVwoRl0LE48wwDQYJKoZIhvcNAQELBQAwazELMAkGA1UEBhMCSVQx
    // ...
    // ...

    // If we want it in PEM format with just LF line-endings:
    const sb = try chilkat.StringBuilder.init();
    defer sb.deinit();
    // Just LF line endings, not CRLF.
    const crlf = false;
    sb.appendLine("-----BEGIN PKCS7-----", crlf) catch {};
    sb.append(sig_base64) catch {};
    sb.appendLine("-----END PKCS7-----", crlf) catch {};
    sb.toLF() catch {};

    // Save to a file.
    sb.writeFile("c:/temp/qa_output/sig.pem", "utf-8", false) catch {};

    // Examine..
    std.debug.print("{s}\n", .{try sb.getAsString(alloc)});

    // Result is:

    // -----BEGIN PKCS7-----
    // MIIWbgYJKoZIhvcNAQcCoIIWXzCCFlsCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
    // ghMXMIIFuzCCA6OgAwIBAgIIVwoRl0LE48wwDQYJKoZIhvcNAQELBQAwazELMAkGA1UEBhMCSVQx
    // DjAMBgNVBAcMBU1pbGFuMSMwIQYDVQQKDBpBY3RhbGlzIFMucC5BLi8wMzM1ODUyMDk2NzEnMCUG
    // A1UEAwweQWN0YWxpcyBBdXRoZW50aWNhdGlvbiBSb290IENBMB4XDTExMDkyMjExMjIwMloXDTMw
    // MDkyMjExMjIwMlowazELMAkGA1UEBhMCSVQxDjAMBgNVBAcMBU1pbGFuMSMwIQYDVQQKDBpBY3Rh
    // bGlzIFMucC5BLi8wMzM1ODUyMDk2NzEnMCUGA1UEAwweQWN0YWxpcyBBdXRoZW50aWNhdGlvbiBS
    // b290IENBMIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEAp8bEpSmkLO/lGMWwUKNvUTuf
    // ClrJwkg4CsIcoBh/kbWHuUA/3R1oHwiD1S0eiKD4j1aPbZkCkpAW1V8IbInX4ay8IMKx4INRimlN
    // AJZaby/ARH6jDuSRzVju3PvHHkVH3Se5CAGfpiEd9UEtL0z9KK3giq0itFZljoZUj5NDKd45Rnij
    // MCO6zfB9E1fAXdKDa0hMxKufgFpbOr3JpyI/gCczWw63igxdBzcIy2zSekciRDXFzMwujt0q7bd9
    // ...
    // ...
    // -----END PKCS7-----
}