Can refer to a set of rules or a system of symbols.
El condigo que encontramos en el antiguo manuscrito resultó ser más complicado de descifrar de lo que pensábamos.
The code we found in the ancient manuscript turned out to be more complicated to decipher than we thought.
El condigo que utilizó para cifrar sus mensajes era tan complicado que pocos lograban descifrarlo.
The code he used to encrypt his messages was so complicated that few managed to decipher it.