Lithoreya (from the Latin. Littera - letter) is a ciphering , a kind of ciphered letter, which was used in old Russian handwritten literature, based on the replacement of some letters of the alphabet by others  . Known litorrhea two kinds: simple and wise . The simple , otherwise called gibberish letter, is the replacement of one consonant letters by others. The easiest way is as follows: putting consonant letters in two rows, in order:
use in the letter the upper letters instead of the lower and vice versa, and the vowels remain unchanged. For example, losham = dictionary , etc. In a sophisticated version, the letters in the rows were arranged in a random order.
The oldest document, known today, containing a fragment ciphered with a simple lithorai, dates from 1229  . This method of encryption was used by Metropolitan Cyprian in his correspondence with Sergius of Radonezh and Theodore Simonovsky   .
The wise litorea involves more complex substitution rules. In various variants that have come down to us, substitutions of entire groups of letters are used, as well as numerical combinations: each consonant letter is assigned a number, and then arithmetic operations are performed on the resulting sequence of numbers (for example, a certain constant is added to all - the key).
At its core, lithorea is a simple replacement cipher , which is easily decoded by modern methods.
- Litorea // The Great Soviet Encyclopedia: [in 51 t.] / Ch. ed. S.I. Vavilov [until 1951], B.A. Vvedensky [since 1951]. - 2nd ed. - Moscow: Soviet Encyclopedia, 1949-1958. - V. 25. - Стр. 286.
- Babash, 2015. Pp. 17
- Babash, 2015. Pp. 32—34.
- The Second Epistle of Metropolitan Ciprian Prep. Sergius (June 23, 1378) . Seditsa.RU. The appeal date is July 14, 2019.
Litorea // Brockhaus and Efron Encyclopedic Dictionary : 86 t. (82 t. And 4 add.). - SPb. , 1890-1907.