Cryptography predates computers, so the only real question is has it shown up in public court records or not. I'd expect plenty of history in treason charges ag

Cryptography predates computers, so the only real question is has it shown up in public court records or not. I'd expect plenty of history in treason charges against caught spies, but whether the records are public or not is a different question. https://en.wikipedia.org/wiki/Book_cipher https://en.wikipedia.org/wiki/Book_cipher https://en.wikipedia.org/wiki/Codebook https://en.wikipedia.org/wiki/Codebook https://en.wikipedia.org/wiki/Poem_code https://en.wikipedia.org/wiki/Poem_code