(Swift 3,4,5...) Convert RSA Private Key to Public Key

Demonstrates how to get a public RSA key from a private RSA key.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    let key = CkoPrivateKey()!

    // Step 1: Load the private key from a source.
    // (Chilkat can load private keys from all types of formats, and from in-memory bytes or encoded strings.
    // see the online reference documentation for more options.)
    var success: Bool = key.loadPemFile("qa_data/pem/VP_Private.pem")
    if success != true {
        print("\(key.lastErrorText!)")
        return
    }

    // Step 2: Get the public key object from the private key object.
    var pubKey: CkoPublicKey? = key.getPublicKey()
    if key.lastMethodSuccess != true {
        print("\(key.lastErrorText!)")
        return
    }

    // Step 3: Save the public key in a desired format. 
    // (Chilkat can load or save public and private keys in many different formats.  See
    // the online reference documentation for more options.)

    // Saves to a PKCS8 PEM file.
    var bPreferPkcs1: Bool = false
    success = pubKey!.savePemFile(bPreferPkcs1, path: "qa_data/pem/VP_Public.pem")
    if pubKey!.lastMethodSuccess != true {
        print("\(pubKey!.lastErrorText!)")
        return
    }

    pubKey = nil

    print("Extracted and saved public key from private key.")

}