Lua

Save a Private Key as an Encrypted PKCS #8 DER File

Demonstrates the Chilkat PrivateKey.SavePkcs8EncryptedFile method, which saves the key as password-protected PKCS #8 DER. The first argument is the password and the second is the destination path. The cipher is selected by Pkcs8EncryptAlg.

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: This is the recommended way to persist a key to disk: the binary .der is encrypted under a passphrase, so a stolen file is useless without it. Reach for it whenever a key is stored or shipped. Choose the encryption cipher with Pkcs8EncryptAlg and source the password securely.

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Lua

local chilkat = require("chilkat")

-- Load a private key to export.
local privKey = chilkat.PrivateKey.new()
local success = privKey:load_pem_file("qa_data/private.pem")
if not success then
    print(privKey.last_error_text)
    return
end

-- The key password is not hard-coded in a real application; obtain it from an interactive
-- prompt, environment variable, or a secrets vault.
local password = "myKeyPassword"

-- Save as password-protected PKCS #8 DER.  The 1st argument is the password and the 2nd is the
-- destination path.  The cipher is selected by the Pkcs8EncryptAlg property.
success = privKey:save_pkcs8_encrypted_file(password, "qa_output/private_pkcs8_enc.der")
if not success then
    print(privKey.last_error_text)
    return
end

print("Saved (encrypted).")