Relating to cryptology; involving the study or practice of secret communication through codes, ciphers, and encryption methods.
From 'cryptology' + '-ical', the variant form of the adjective that became standard in academic and government contexts by the late 20th century.
'Cryptological' sounds more official and scientific than 'cryptographic,' which is why military and intelligence agencies prefer it—adding that extra syllable makes breaking enemy codes sound like a respectable academic discipline.
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