# Method Crypto.Substitution()->set_rot_key()

Method set_rot_key

  ``this_program` set_rot_key(`void`|`int` `steps`, `void`|`array`(`string`) `alphabet`)`

Description

  Sets the key to a ROT substitution system. `steps` defaults to 13 and `alphabet` defaults to A-Z, i.e. this function defaults to set the substitution crypto to be ROT13. If no alphabet is given the key will be case insensitive, e.g. the key will really be two ROT13 alphabets, one a-z and one A-Z, used simultaneously.