Delta Cipher

[magnesium]

Yes, I like the Naibbe cipher. I would like to see what happens to the long-range correlations if an actual card-drawing process is implemented, because Greshko's implementation from which he drew the statistics in his paper actually treats the table selections as independent events. He seems to think it wouldn't make much difference to use an actual card-draw, and maybe he's right, but I would still like to see the degree of the effect.

I agree that it would be interesting to test this further. To make long-range correlations work in the context of a homophonic substitution cipher without assuming a fine-tuned plaintext structure (i.e., let's assume a plaintext Hurst exponent of 0.5), I suspect that there need to be long-range correlations in the table selection process that are reliably carried by the cipher's homophone inventories. That is to say, each "table" consists of structurally distinctive glyph strings, so if there are long-range correlations in the table selection sequence, the resulting glyph strings reliably bake those correlations into the ciphertext.

Reconciling this with the current Naibbe cipher probably would require revising the tables, at a minimum. The bigram prefix and suffix inventories within the current Naibbe cipher's tables were populated specifically assuming random respacing and letter-by-letter table selection. So even if long-range correlations were imposed on the table selection sequence within the current cipher, I'm not sure that the resulting ciphertext would have strong long-range correlations, as the current inventories of bigram prefixes and suffixes would essentially act as random noise.

I have a lot to learn about the mathematics of this, but I don't understand why that should be the case. So long as the underlying letters that your tables are representing have unequal distribution, which in the plaintext they do, then shouldn't the correlation be able to show through even if the glyphs have been randomly assigned? Or is it just that it's far too weak?

To be clear, I haven't tried this systematically yet so cannot be fully sure. My concern is that the resulting long-range correlations would not be strong enough to replicate what's observed in the VMS (Hurst exponent of 0.65-0.7).