PureBasic

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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IncludeFile "CkPrivateKey.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  Load a private key to export.
    privKey.i = CkPrivateKey::ckCreate()
    If privKey.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPrivateKey::ckLoadPemFile(privKey,"qa_data/private.pem")
    If success = 0
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    ;  The key password is not hard-coded in a real application; obtain it from an interactive
    ;  prompt, environment variable, or a secrets vault.
    password.s = "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 = CkPrivateKey::ckSavePkcs8EncryptedFile(privKey,password,"qa_output/private_pkcs8_enc.der")
    If success = 0
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    Debug "Saved (encrypted)."


    CkPrivateKey::ckDispose(privKey)


    ProcedureReturn
EndProcedure