EN
The paper is devoted to analyzing the phenomenon of the cipher, which appears in the Old Polish correspondence and diary prose. The analysis will turn in the direction of texts written by persons involved in hidden amorous relationships, objectionable from the point of view the official social norms, given the fact that the lovers commit treason against wedded partners. Letters by Sobieski and Marysieńka served as a starting point and then reflection also included correspondence from Magdalena Czapska and Hieronim Florian Radziwiłł. Due to a distinct species convention, somewhat different perspective has appointed diary of enamored Jan Krzysztof Biegański. Considerations apply to both the nature of ciphers used in these texts, as well as the causes and functions of their use which, despite appearances, did not involve only with the need to hide a sinful relationship. The issue of readability of encrypted texts and the ability to discover covert meanings has also been raised.