B4X

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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Dim success As Boolean = False

'  Load a private key to export.
Dim privKey As ChilkatPrivateKey
privKey.Initialize("privKey")
success = privKey.LoadPemFile("qa_data/private.pem")
If success = False Then
    Log(privKey.LastErrorText)
    Return
End If


'  The key password is not hard-coded in a real application; obtain it from an interactive
'  prompt, environment variable, or a secrets vault.
Dim password As String = "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 = False Then
    Log(privKey.LastErrorText)
    Return
End If

Log("Saved (encrypted).")