Litorea

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 ^[1] . 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 ^[2] . This method of encryption was used by Metropolitan Cyprian in his correspondence with Sergius of Radonezh and Theodore Simonovsky ^{[3] [4]} .

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.