Zig

Set the DKIM Signing Private Key

Demonstrates the Chilkat Dkim.SetDkimPrivateKey method, which supplies the RSA private key used by DkimSign. The only argument is a PrivateKey object. The source key may be destroyed after this returns, and the configured key can be reused for multiple signatures.

Note: 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: DKIM proves a message really came from its domain by signing it with a private key that only the domain owner holds; recipients verify with the matching public key published in the domain's DNS. This method loads that private half into the Dkim object once, so a mail server can sign every outgoing message without re-reading the key each time. Because the key is the domain's signing secret, it should be protected like any other private key and never committed to source.

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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 Dkim.SetDkimPrivateKey method, which supplies the RSA private key used by
    // DkimSign.  The only argument is a PrivateKey object.

    const dkim = try chilkat.Dkim.init();
    defer dkim.deinit();

    // Load the RSA private key that corresponds to the public key published in the domain's DNS.
    const priv_key = try chilkat.PrivateKey.init();
    defer priv_key.deinit();
    priv_key.loadPemFile("qa_data/dkim_private.pem") catch {
        std.debug.print("{s}\n", .{try priv_key.getLastErrorText(alloc)});
        return;
    };

    // Copy the key into the Dkim object.  The PrivateKey object may be destroyed afterward, and the
    // configured key can be reused for multiple signatures.
    dkim.setDkimPrivateKey(priv_key) catch {
        std.debug.print("{s}\n", .{try dkim.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("DKIM private key configured.\n", .{});
}