Sirvi Autor "Biermann, Norbert" järgi

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Antonio Elio “Cipher” and his Polyphonic-Syllabic Cipher
(Tartu University Library, 2025) Lasry, George; Biermann, Norbert; Simonetta, Marcello; Antal, Eugen; Marák, Pavol
Antonio Elio (Helius) (1506–1576) was a Roman Catholic prelate who served as Bishop of Capodistria and Pola and Titular Patriarch of Jerusalem. Also a prolific cryptographer in the service of Pope Paul III, he is credited for the invention of polyphonic ciphers. In this article, we provide an overview of his career and work in cryptography and describe an ingenious polyphonic-syllabic cipher he designed. Although several matching plaintext-ciphertext segments were available, reconstructing the cipher key required a significant and unusual amount of time, underscoring the cipher’s high level of security. Ciphertext-only cryptanalysis for such a cipher would be extremely difficult and nearly impossible, even with modern computing, without prior knowledge of the principles of its complex design.
What Encryption Errors Can Reveal: Cross-Cipher Errors in Mary Queen of Scots’ Letters
(Tartu University Library, 2024) Biermann, Norbert; Tomokiyo, Satoshi; Lasry, George; Waldispühl, Michelle; Megyesi, Beáta
In the recently deciphered letters from Mary Queen of Scots, a large number of systematic encryption errors were found and attributed to confusion as a result of concurrently using at least one other cipher key to communicate with a different recipient. In this paper, we further analyze such cross-cipher errors in those letters and identify additional cipher keys involved. This analysis also reveals valuable insights on the secret communications of Mary, Queen of Scots. We employ several techniques including statistical analysis, which may be applied to the analysis of encryption errors in other collections of historical enciphered documents.