Abstract: A computing platform is configured to: (i) obtain a pool of available words for use in generating four-word passphrases, (ii) generate a candidate batch of four-word passphrases using the pool of available words, (iii) identify one or more duplicate four-word passphrases in the candidate batch and then filter the identified one or more duplicate four-word passphrases out of the candidate set; (iv) based on the filtered candidate batch of four-word passphrases, generate a new batch of four-word passphrases for use on direct mail; and (v) release the new batch of four-word passphrases for use on direct mail.