# Method Crypto.Substitution()->set_ACA_K3_key()

Method set_ACA_K3_key

  ``this_program` set_ACA_K3_key(`string` `key`, `int` `offset`, `void`|`array`(`string`) `alphabet`)`

Description

  Sets the key according to ACA K3 key generation. Both the plaintext and the cryptogram alphabets are prepended with a keyword `key`, which characters are removed from the rest of the alphabet. The plaintext alphabet is then rotated `offset` number of steps.