What was the verb(s) the Romans used when the hide/encrypt a message in another text (and also the antonym "to decipher")? After consulting Döderlein's Hand-book of Latin Synonymes (Celare), it was difficult to fixate on a word.

Latin Vicipaedia (Cryptographia) seems to suggest obscuro ("Cryptographi plerumque mathematicis rationibus ad nuntia obscuranda utuntur") or simply scribo [secretum nuntium] ("Cryptographia est ars scientiaque nuntiorum secretorum scribendorum et interpretandorum")

There surely are classical as well as medieval examples but I could not find any.


1 Answer 1


Here is one relevant passage in Suetonius, Divus Iulius, 56.6, describing the Caesar cipher:

Extant et ad Ciceronem, item ad familiares domesticis de rebus, in quibus, si qua occultius perferenda erant, **per notas scripsit**, id est sic structo litterarum ordine, ut nullum uerbum effici posset: quae si qui inuestigare et persequi uelit, quartam elementorum litteram, id est D pro A et perinde reliquas commutet.

There are extant likewise some letters from him to Cicero, and others to his friends, concerning his domestic affairs; in which, if there was occasion for secrecy, he wrote in cyphers; that is, he used the alphabet in such a manner, that not a single word could be made out. The way to decipher those epistles was to substitute the fourth for the first letter, as D for A, and so for the other letters respectively.
(translation by Alexander Thomson, 1889)

See Perseus for more context.

The bit I highlighted gives one answer to your question: per notas scribere.

  • Nice. It also suggests investigare to decipher
    – d_e
    Commented Aug 12, 2023 at 20:46
  • I'm guessing that "rot-III" wasn't in common usage. Commented Aug 13, 2023 at 0:43
  • Worth noting (haha) that Suetonius uses the same expression describing Augustus' even simpler cipher (Div. Aug. 88). Commented Dec 9, 2023 at 22:20

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