@Override
    protected void engineInitSign(PrivateKey privateKey) throws InvalidKeyException {
        initInternal(OpenSSLKey.fromPrivateKey(privateKey), true);
    }
Configures the public key algorithm context ({@code EVP_PKEY_CTX}) associated with this
operation.

<p>The default implementation does nothing.

@param ctx reference to the context ({@code EVP_PKEY_CTX}).
common/src/main/java/org/conscrypt/OpenSSLSignature.java