Rust

Add a Detached Signature (Header Placement Control)

Demonstrates the Chilkat Mime.AddDetachedSignature2 method, which creates the same multipart/signed structure as AddDetachedSignature, with a second argument controlling whether the existing message header fields are transferred to the new outer entity.

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: Signing wraps the content in a new outer multipart/signed, which raises the question of where the message-level headers (Subject, From, To) should live. This variant lets you choose: transfer them up to the outer entity so the signed message looks like a normal email, or leave them on the inner part. Transferring is typical for email; the finer control matters when the signed entity is embedded in a larger structure.

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Rust


let mime = chilkat::Mime::new();
if mime.set_body_from_plain_text("This message will be signed.").is_err() {
    println!("{}", mime.last_error_text());
    return;
}

// Load the signing certificate (which must have access to its private key) from a PFX file.
// The PFX password should come from a secure source rather than being hard-coded.
let pfx_password = "myPfxPassword".to_string();
let cert = chilkat::Cert::new();
if cert.load_pfx_file("qa_data/signer.pfx", &pfx_password).is_err() {
    println!("{}", cert.last_error_text());
    return;
}

// AddDetachedSignature2 is the same as AddDetachedSignature, but the 2nd argument controls whether
// the existing message header fields are transferred to the new outer multipart/signed entity.
let transfer_header_fields = true;
if mime.add_detached_signature2(&cert, transfer_header_fields).is_err() {
    println!("{}", mime.last_error_text());
    return;
}

if mime.save_mime("qa_output/signed.eml").is_err() {
    println!("{}", mime.last_error_text());
    return;
}

println!("Detached signature added (headers transferred).");