Java

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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Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    //  Load a private key to export.
    CkPrivateKey privKey = new CkPrivateKey();
    success = privKey.LoadPemFile("qa_data/private.pem");
    if (success == false) {
        System.out.println(privKey.lastErrorText());
        return;
        }

    //  The key password is not hard-coded in a real application; obtain it from an interactive
    //  prompt, environment variable, or a secrets vault.
    String 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 == false) {
        System.out.println(privKey.lastErrorText());
        return;
        }

    System.out.println("Saved (encrypted).");
  }
}