Zig

Specify a Certificate for Encrypted Email

Demonstrates the Chilkat Email.AddEncryptCert method, which explicitly specifies a certificate to use when sending encrypted email. Call it once per recipient certificate; ClearEncryptCerts clears the list. This example loads a recipient certificate, registers it, and enables encrypted sending.

Background: When encrypting to multiple people, each recipient needs to be able to decrypt with their own private key. S/MIME handles this by encrypting the message's one-time content key separately under each recipient's public certificate and including all of those wrapped keys in the message. AddEncryptCert is how you build that recipient list — one call per certificate — giving explicit control over exactly whose certificates are used rather than relying on automatic lookup.

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

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

    // Demonstrates the AddEncryptCert method, which explicitly specifies a certificate for
    // sending encrypted email.  Call it once per recipient certificate.  Use ClearEncryptCerts
    // to clear the list.

    const email = try chilkat.Email.init();
    defer email.deinit();
    email.setSubject("Encrypted email");
    email.setBody("Encrypted to the specified recipient certificate(s).");
    email.setFrom("alice@example.com");
    email.addTo("Bob", "bob@example.com") catch {};

    // Load a recipient certificate (public key) and add it to the encryption cert list.
    const cert = try chilkat.Cert.init();
    defer cert.deinit();
    cert.loadFromFile("qa_data/certs/recipient.cer") catch {
        std.debug.print("{s}\n", .{try cert.getLastErrorText(alloc)});
        return;
    };

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

    // Request encrypted sending.
    email.setSendEncrypted(true);

    std.debug.print("Added the recipient's encryption certificate.\n", .{});

    // Note: The path "qa_data/certs/recipient.cer" is a relative local filesystem path,
    // relative to the current working directory of the running application.
}