# Method Crypto.Substitution()->set_ACA_K4_key()

Method set_ACA_K4_key

  ``this_program` set_ACA_K4_key(`string` `key1`, `string` `key2`, `void`|`int` `offset`, `void`|`array`(`string`) `alphabet`)`

Description

  Sets the key according to ACA K4 key generation. Both the plaintext and the cryptogram alphabets are prepended with the keywords `key1` and `key2`. The plaintext alphabet is then rotated `offset` number of steps.