(Swift 3,4,5...) Encrypt Already Existing Zip

To encrypt an already existing non-encrypted .zip, the application must open the .zip, set the encryption related properties, and then re-write.

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

func chilkatTest() {
    // This requires the Chilkat Zip API to have been previously unlocked.
    // See Unlock Chilkat Zip for sample code.

    let zip = CkoZip()!

    // Open an unencrypted .zip
    var success: Bool = zip.open("qa_data/zips/test.zip")
    if success != true {
        print("\(zip.lastErrorText!)")
        return
    }

    // Unzip to a temp directory.
    var numFilesUnzipped: Int = zip.unzip("qa_output/tmp").intValue
    if numFilesUnzipped < 0 {
        print("\(zip.lastErrorText!)")
        return
    }

    // Clear the zip object.
    zip.newZip("qa_output/aesTest.zip")

    // Indicate that 128-bit AES encryption is to be used when writing the .zip
    zip.encryption = 4
    zip.encryptKeyLength = 128

    // Set the password.
    zip.encryptPassword = "secret"

    // Append the files.
    zip.appendFromDir = "qa_output/tmp"
    success = zip.appendFiles("*.*", recurse: true)
    if success != true {
        print("\(zip.lastErrorText!)")
        return
    }

    // Write the .zip and close it.
    success = zip.writeAndClose()
    if success != true {
        print("\(zip.lastErrorText!)")
        return
    }

    print("Success.")

}