(Java) Convert PuTTY Private Key (ppk) to OpenSSH (pem)

Convert a PuTTY format private key file (.ppk) to OpenSSH (.pem).

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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[])
  {
    CkSshKey key = new CkSshKey();

    boolean success;

    // Load an unencrypted or encrypted PuTTY private key.

    // If  your PuTTY private key is encrypted, set the Password
    // property before calling FromPuttyPrivateKey.
    // If your PuTTY private key is not encrypted, it makes no diffference
    // if Password is set or not set.
    key.put_Password("secret");

    // First load the .ppk file into a string:
    String keyStr;
    keyStr = key.loadText("putty_private_key.ppk");

    // Import into the SSH key object:
    success = key.FromPuttyPrivateKey(keyStr);
    if (success != true) {
        System.out.println(key.lastErrorText());
        return;
        }

    // Convert to an encrypted or unencrypted OpenSSH key.

    // First demonstrate converting to an unencrypted OpenSSH key
    String unencryptedKeyStr;
    boolean bEncrypt = false;
    unencryptedKeyStr = key.toOpenSshPrivateKey(bEncrypt);
    success = key.SaveText(unencryptedKeyStr,"unencrypted_openssh.pem");
    if (success != true) {
        System.out.println(key.lastErrorText());
        return;
        }

    // Save to an encrypted OpenSSH PEM file:
    String encryptedKeyStr;
    bEncrypt = true;
    key.put_Password("myPassword");
    encryptedKeyStr = key.toOpenSshPrivateKey(bEncrypt);
    success = key.SaveText(encryptedKeyStr,"encrypted_openssh.pem");
    if (success != true) {
        System.out.println(key.lastErrorText());
        return;
        }

    System.out.println("Done!");
  }
}