Abstract: Despite the extensive bibliographical material, scientific study of the life and work of Nostradamus has only relatively recently begun. Currently, it includes a detailed examination of the predictor's biography and historical-philological commentaries on the quatrains. The unordered arrangement of the quatrains is one of the main problems hindering the understanding of the prophecies. In particular, it has been discovered that many quatrains describe presumed future events through comparison with the past and, therefore, cannot be adequately understood without a reasoned arrangement by dates. Although Nostradamus himself unequivocally states in an epistle to King Henry II that the quatrains should be arranged using the biblical chronology he provided, with a reference point determined by the retrograde movements of planets (1606 year, as shown by prof. Brind'Amour), discussions of such cryptographic approaches were absent in Nostradamus literature until now. For the first time, this work presents a detailed argument for the hypothesis that Nostradamus used a modified "scytale" algorithm to encrypt the correct sequence of quatrains and assign them specific dates. It is shown that the predictor indeed employed cyclically repeating biblical chronologies placed in the epistle to King Henry II for this purpose. The final date of the prophecies turns out to be the year 2242, close to the end of the 6,000 years in the Jewish calendar (2240 AD) and the completion of the cycle of planetary epochs in the astrological concept of Abraham ibn Ezra (2241 AD), which aligns well with existing historical research. The analysis results indicate that although the Prophecies were published in parts, they form a coherent work following a strict plan. Consequently, the obtained results are relevant to the history of cryptography in Europe and have significant implications for a correct understanding of Nostradamus' texts.