04-01-2022, 04:07 PM
What I was inspired by, was the so-called "litoreia".
Generally, litoreia is a collective term for the whole family of medieval Russian cryptographic techniques. There were "simple litoreia" techniques which were basically simple substitution ciphers. And there was "complex" or the so-called "wise" litoreia, wherein numerical values of Cyrillic alphabet letters were utilized.
With the wise litoreia, the whole alphabet was divided into four groups. The first group of letters had no numerical meanings, so they were translated directly as such into the ciphertext. The second, third and fourth groups were comprised of letters associated with meanings of units, tens and hundreds, respectively. A cipher token was associated with each of these three groups - for example, a dot for group 2, a cross for group 3 and a dash for group 4. Then each letter was encoded with the respective number of respective tokens. For example, letter "A" had the numeric meaning of 1, hence it was encoded with a dot. Letter "M" had the meaning of 40, so it would be encoded with four crosses, while letter "C" meant 200 and would be encoded with two dashes. Messages thus encoded are known in Russia since at least 14th century, if I am not mistaken. The most famous of those contains the disputable statement "all priests are thieves".
Now imagine that when writing the encrypted message you place all tokens of each letter vertically. Then you split this slip of paper in two halves along a horizontal line, leaving the upper set of tokens on one slip of paper, and the lower set - on the other slip. You then store the two slips in separate places for reliablility. What is thus produced are two portions of the ciphertext, each of which cannot be deciphered by itself, and which can only be deciphered if possessed together and matched against each other (unless perhaps a good deal of brute force is applied to a single portion in one's possession).
The principle is very elegant, but it is known to me from fiction (forum participants from the ex-USSR countries will guess the novel that I mean), and I do not know if it was actually known and used in real life. If it is a real-life principle then this is an excellent example of a "spatial spread".
Generally, litoreia is a collective term for the whole family of medieval Russian cryptographic techniques. There were "simple litoreia" techniques which were basically simple substitution ciphers. And there was "complex" or the so-called "wise" litoreia, wherein numerical values of Cyrillic alphabet letters were utilized.
With the wise litoreia, the whole alphabet was divided into four groups. The first group of letters had no numerical meanings, so they were translated directly as such into the ciphertext. The second, third and fourth groups were comprised of letters associated with meanings of units, tens and hundreds, respectively. A cipher token was associated with each of these three groups - for example, a dot for group 2, a cross for group 3 and a dash for group 4. Then each letter was encoded with the respective number of respective tokens. For example, letter "A" had the numeric meaning of 1, hence it was encoded with a dot. Letter "M" had the meaning of 40, so it would be encoded with four crosses, while letter "C" meant 200 and would be encoded with two dashes. Messages thus encoded are known in Russia since at least 14th century, if I am not mistaken. The most famous of those contains the disputable statement "all priests are thieves".
Now imagine that when writing the encrypted message you place all tokens of each letter vertically. Then you split this slip of paper in two halves along a horizontal line, leaving the upper set of tokens on one slip of paper, and the lower set - on the other slip. You then store the two slips in separate places for reliablility. What is thus produced are two portions of the ciphertext, each of which cannot be deciphered by itself, and which can only be deciphered if possessed together and matched against each other (unless perhaps a good deal of brute force is applied to a single portion in one's possession).
The principle is very elegant, but it is known to me from fiction (forum participants from the ex-USSR countries will guess the novel that I mean), and I do not know if it was actually known and used in real life. If it is a real-life principle then this is an excellent example of a "spatial spread".