To break or analyze a secret code; to decipher encrypted messages without the original key.
From cryptanalysis + '-ize' verb suffix (like 'analyze' itself), created as a backformation in the mid-20th century for active codebreaking.
The verb 'cryptanalyze' is relatively new—most older military and intelligence documents used noun forms instead, which is why you see 'perform cryptanalysis' more often than 'cryptanalyze' in historical texts.
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