Rust Requires Chilkat v11.0.0+

Duplicate openssl pkey -in private.pem -pubout -out pubkey.pem

See more OpenSSL Examples

How to output the public part of a private key: Demonstrates how to duplicate this OpenSSL command:

openssl pkey -in private.pem -pubout -out pubkey.pem

Rust

let pkey = chilkat::PrivateKey::new();

// Load the private key from an PEM file:
if pkey.load_pem_file("private.pem").is_err() {
    println!("{}", pkey.last_error_text());
    return;
}

let pub_key = chilkat::PublicKey::new();
let _ = pkey.to_public_key(&pub_key);

if pub_key.save_pem_file(false, "pubKey.pem").is_err() {
    println!("{}", pub_key.last_error_text());

    return;
}

println!("Success.");