PowerShell

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.

Chilkat PowerShell Downloads

Download Chilkat for PowerShell

PowerShell

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

#  Load a private key to export.
$privKey = New-Object Chilkat.PrivateKey
$success = $privKey.LoadPemFile("qa_data/private.pem")
if ($success -eq $false) {
    $($privKey.LastErrorText)
    exit
}

#  The key password is not hard-coded in a real application; obtain it from an interactive
#  prompt, environment variable, or a secrets vault.
$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 = $privKey.SavePkcs8EncryptedFile($password,"qa_output/private_pkcs8_enc.der")
if ($success -eq $false) {
    $($privKey.LastErrorText)
    exit
}

$("Saved (encrypted).")