Roger Bacon wrote about binary notation in the 13th century, although he called bits `fingers'. John Wilkins credited Bacon in his book Mercury, or the Silent and Swift Messenger published in 1641.

Wilkins' book is basically a tutorial on communications security (COMSEC) that touches on channel coding, reliability, secrecy, key management, cryptanalysis, OPSEC, and data compression.

ETA: Wilkins takes a clear position on the full disclosure debate but cautions of the hazard of experimenting with crypto technologies:

    `...the chiefe experiments are of such nature, that
    they cannot be frequently practised, without just cause
    of suspicion, when it is in the Magistrates power to
    prevent them.'