Zig

S/MIME Decrypt using Certificate and Private Key in Apple Keychain

See more Apple Keychain Examples

Decrypts S/MIME using a certificate with private key found in the Apple Keychain. Zig

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

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

    const cert = try chilkat.Cert.init();
    defer cert.deinit();

    // Load the certificate to be used for decryption by the Subject Common Name
    // On MacOS and iOS, Chilkat will search the Keychain(s) for the matching certificate.
    // Note: The private key must be present to decrypt.
    cert.loadByCommonName("My Cert") catch {
        std.debug.print("{s}\n", .{try cert.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("Cert has private key: {}\n", .{cert.hasPrivateKey()});

    // Load the MIME to be decrypted.
    // We encrypted using this example:  S/MIME Encrypt using Certificate in Apple Keychain
    const mime = try chilkat.Mime.init();
    defer mime.deinit();
    mime.loadMimeFile("./encrypted.mime") catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("{s}\n", .{try mime.getMime(alloc)});
    std.debug.print("----\n", .{});

    // Here's the encrypted MIME:

    // Subject: test
    // SomeHeader: 123
    // Content-Type: application/x-pkcs7-mime; name="smime.p7m"; smime-type="enveloped-data"
    // Content-Disposition: attachment; filename="smime.p7m"
    // Content-Transfer-Encoding: base64
    //
    // MIICSwYJKoZIhvcNAQcDoIICPDCCAjgCAQAxggGzMIIBrwIBADCBljCBgTELMAkGA1UEBhMCSVQx
    // EDAOBgNVBAgMB0JlcmdhbW8xGTAXBgNVBAcMEFBvbnRlIFNhbiBQaWV0cm8xFzAVBgNVBAoMDkFj
    // dGFsaXMgUy5wLkEuMSwwKgYDVQQDDCNBY3RhbGlzIENsaWVudCBBdXRoZW50aWNhdGlvbiBDQSBH
    // MwIQPCWvkSv8oQ7xRmEHJ6TzEDANBgkqhkiG9w0BAQEFAASCAQB3VZvHRE5EWxug7Sckpcz1ucDZ
    // YiTKiqmyPt75MhzNRQLtKFx/jWwlemUwnPMzeu6yutCkZ74Bdn7MBsfDqV3bUz43wAu+fRBteGvF
    // mTc00MfY8L7o8dkpj4AqAOCj4hKQzbSE99GvSzyXcPE2Gm5NrOPtKxqfFqbBRTCb4fBZP84LaL+x
    // rnYfrM4qXTppixyN8iFYCd4maEbMu/GA5o+j0BkDDnx42pILDoAGV/ERyx55Y3Nc2Mhm/cITBMNn
    // g7uS9KPrlYizNaqVu09Hi9jg4gdZaRiTjUqg05tSOk/YqIQxTgfscwSPY92/ewpI6e1EHtLt8Q33
    // gWCbERptSntUMHwGCSqGSIb3DQEHATAdBglghkgBZQMEAQIEENm1AxeXlEMx7p6McjHIj5CAUEQj
    // 0GuJ5LnTqiqIjOiwmwNidl1N1TRluxX5vAQvwBuYE6bQK4+i04yn2Av3cucW4kvxgP2Nmni+XgQt
    // aPPKlasaVceEeZ15IYjw77/m3YYn

    // -------------------------------------
    // Decrypt the MIME.
    mime.decryptUsingCert(cert) catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    // -------------------------------------
    // Note: A password dialog may be shown, possibly twice, when accessing the private key.
    // See the following blog post explaining how to suppress the dialog:
    // Suppress Password Dialog when Accessing Private Key in Apple Keychain

    // Show the unencrypted MIME
    std.debug.print("{s}\n", .{try mime.getMime(alloc)});

    // Here's the decrypted MIME

    // Subject: test
    // SomeHeader: 123
    // Content-Type: text/plain
    //
    // This is the body.
}