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De furtivis Literarum Notis (1563), Giambattista della Porta

By H Dominic W Stiles, on 26 February 2020

One of our treasures and oldest books, is Giambattista della Porta‘s book on cryptography, De furtivis Literarum Notis (1563).  Della Porta (ca. 1535-1615) was born near Naples.  He was another of those great Italians of that age, like Cardano, who pushed forward the boundaries of knowledge.  He has been called the towering figure of cryptography in that period.

This has nothing to do with hearing or deafness.  When Selwyn Oxley was acquiring his Ephphatha library, this would probably have interested him because it was a system of communication.

According to the Springer Encyclopedia of Cryptography and Security, there is a maxim named after him –

Della Porta’s maxim: Only a cryptanalyst, if anybody, can judge the security of a cryptosystem (Auguste Kerckhoffs, formulating the knowledge of the sixteenth century cryptologist Giambattista Della Porta, Kerckhoffs (1883) Auguste, La Cryptographie militaire. Journal des Sciences Militaires, 9 (January) 5–38, (February) 161–191).

Our copy is sadly not perfect – it has a water stain and a missing cipher wheel, or volvelle.

You can read more about him on Wikipedia –



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