(Mono C#) Convert PuTTY Private Key (ppk) to OpenSSH (pem)

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

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Chilkat.SshKey key = new Chilkat.SshKey();

bool 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.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) {
    Debug.WriteLine(key.LastErrorText);
    return;
}

// Convert to an encrypted or unencrypted OpenSSH key.

// First demonstrate converting to an unencrypted OpenSSH key
string unencryptedKeyStr;
bool bEncrypt = false;
unencryptedKeyStr = key.ToOpenSshPrivateKey(bEncrypt);
success = key.SaveText(unencryptedKeyStr,"unencrypted_openssh.pem");
if (success != true) {
    Debug.WriteLine(key.LastErrorText);
    return;
}

// Save to an encrypted OpenSSH PEM file:
string encryptedKeyStr;
bEncrypt = true;
key.Password = "myPassword";
encryptedKeyStr = key.ToOpenSshPrivateKey(bEncrypt);
success = key.SaveText(encryptedKeyStr,"encrypted_openssh.pem");
if (success != true) {
    Debug.WriteLine(key.LastErrorText);
    return;
}

Debug.WriteLine("Done!");