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C#

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

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

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C#
bool success = false;

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

//  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!");