Zig

Encrypt MIME for a Recipient Certificate

Demonstrates encrypting the current MIME entity for a single recipient using the Mime.Encrypt method. The entity is replaced with CMS/PKCS #7 encrypted S/MIME that only the holder of the recipient's private key can read.

The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background. S/MIME encryption uses the recipient's public certificate to protect a message so that only the matching private key can recover it. The recipient certificate must be RSA-based. Only the recipient's public key is needed to encrypt—the private key is required to decrypt.

Chilkat Zig Downloads

Download Chilkat for Zig

Zig

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

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

    const mime = try chilkat.Mime.init();
    defer mime.deinit();
    mime.setBodyFromPlainText("This message will be encrypted.") catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    // Load the recipient's certificate (public key only is sufficient for encrypting).
    const cert = try chilkat.Cert.init();
    defer cert.deinit();
    cert.loadFromFile("qa_data/recipient.cer") catch {
        std.debug.print("{s}\n", .{try cert.getLastErrorText(alloc)});
        return;
    };

    // Encrypt for the recipient.  The entity is replaced with CMS/PKCS #7 encrypted S/MIME that only
    // the holder of the recipient's private key can decrypt.  The certificate must be RSA-based.
    mime.encrypt(cert) catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    mime.saveMime("qa_output/encrypted.eml") catch {
        std.debug.print("{s}\n", .{try mime.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("Message encrypted.\n", .{});
}