Options

Delta Cipher

Index
Delta Cipher
Delta Cipher

Fontanellean > 15-02-2026, 03:40 PM

Hello, All.

I am new, so please forgive my lack of completely understanding the current state of the research.

I was wondering what the current status is of the hypothesis that Voynichese is a delta cipher, in other words, the idea that it is the transition from one word to the next that encodes information -- which characters are dropped and added and where, etc. This could encode plaintext letters or the numbers of an intermediate Polybius Square. I know papers like those of Timm and Schinner looked at word similarity in transitions, but I couldn't tell the degree to which this sort of encoding was ruled out. I also would have expected modern professional cryptography to have cracked it by now if this were the case, but perhaps I have too much faith in that.
RE: Delta Cipher

oshfdk > 15-02-2026, 03:53 PM

(15-02-2026, 03:40 PM)Fontanellean Wrote: You are not allowed to view links. Register or Login to view.I was wondering what the current status is of the hypothesis that Voynichese is a delta cipher, in other words, the idea that it is the transition from one word to the next that encodes information -- which characters are dropped and added and where, etc. This could encode plaintext letters or the numbers of an intermediate Polybius Square. I know papers like those of Timm and Schinner looked at word similarity in transitions, but I couldn't tell the degree to which this sort of encoding was ruled out. I also would have expected modern professional cryptography to have cracked it by now if this were the case, but perhaps I have too much faith in that.

Hi,

I'm not sure any encoding scheme has been conclusively ruled out, but some of them, like simple substitution, only seem possible in a combination with a very exotic language or very strange plaintext.

I'm not even sure how one can "rule out" an encoding scheme without any idea of what the plaintext should look like.

I think there have been a few discussions of ciphers that employ character-to-character transitions to encode information, for example: You are not allowed to view links. Register or Login to view.
RE: Delta Cipher

Rafal > 15-02-2026, 04:04 PM

What is delta cipher? Could you give examples?
RE: Delta Cipher

nablator > 15-02-2026, 04:37 PM

(15-02-2026, 03:53 PM)oshfdk Wrote: You are not allowed to view links. Register or Login to view.I think there have been a few discussions of ciphers that employ character-to-character transitions to encode information

Also your verbose self-citation cipher: You are not allowed to view links. Register or Login to view.

It works on the idea that information is in "which characters are dropped and added". Very difficult (impossible?) to rule out.
RE: Delta Cipher

Fontanellean > 15-02-2026, 08:24 PM

(15-02-2026, 04:37 PM)nablator Wrote: You are not allowed to view links. Register or Login to view.
(15-02-2026, 03:53 PM)oshfdk Wrote: You are not allowed to view links. Register or Login to view.I think there have been a few discussions of ciphers that employ character-to-character transitions to encode information

Also your verbose self-citation cipher: You are not allowed to view links. Register or Login to view.

It works on the idea that information is in "which characters are dropped and added". Very difficult (impossible?) to rule out.

That is exactly the sort of family of ciphers I had in mind: Encoding by letters added or dropped from the previous word, making the meaning of a given word dependent on the previous word. There are many different ways that could work, but it's a theory that to me seems attentive to many of the properties the text needs to have.
RE: Delta Cipher

nablator > 15-02-2026, 08:27 PM

(15-02-2026, 08:24 PM)Fontanellean Wrote: You are not allowed to view links. Register or Login to view.There are many different ways that could work, but it's a theory that to me seems attentive to many of the properties the text needs to have.

It's not nearly restrictive enough. You need more constraints than frequent self-similarity to explain Voynichese. Also ambiguous word breaks make ciphers relying on words unlikely. There is a workaround with a possible re-parsing of tokens ignoring spaces that could also explain the rigid word structure.
RE: Delta Cipher

Fontanellean > 15-02-2026, 09:14 PM

(15-02-2026, 08:27 PM)nablator Wrote: You are not allowed to view links. Register or Login to view.
(15-02-2026, 08:24 PM)Fontanellean Wrote: You are not allowed to view links. Register or Login to view.There are many different ways that could work, but it's a theory that to me seems attentive to many of the properties the text needs to have.

It's not nearly restrictive enough. You need more constraints than frequent self-similarity to explain Voynichese. Also ambiguous word breaks make ciphers relying on words unlikely. There is a workaround with a possible re-parsing of tokens ignoring spaces that would also explain the rigid word structure.

That particular example isn't restrictive enough, but I'm simply referring to the general family of delta ciphers. At least they predict a general trend toward word similarity and phrase similarity for someone lacking the aid of a computer. I just want to make sure anything I investigate is deep within a parameter space that hasn't been excluded.
RE: Delta Cipher

nablator > 15-02-2026, 09:37 PM

(15-02-2026, 09:14 PM)Fontanellean Wrote: You are not allowed to view links. Register or Login to view.That particular example isn't restrictive enough, but I'm simply referring to the general family of delta ciphers. At least they predict a general trend toward word similarity and phrase similarity for someone lacking the aid of a computer. I just want to make sure anything I investigate is deep within a parameter space that hasn't been excluded.

Delta ciphers haven't been excluded or investigated AFAIK. How would you investigate something so elusive?

I did some statistics on oshfdk's cipher (without special rule to ignore text until the first p/f) on paragraphs of the VMS to see how many differences exist within the cipher's specification (max. 1 char added, max. 1 char removed): they could store between 5000 and 15000 characters of plaintext depending on how lines are reparsed (or not).
RE: Delta Cipher

Fontanellean > 15-02-2026, 11:31 PM

(15-02-2026, 09:37 PM)nablator Wrote: You are not allowed to view links. Register or Login to view.Delta ciphers haven't been excluded or investigated AFAIK. How would you investigate something so elusive?

I did some statistics on oshfdk's cipher (without special rule to ignore text until the first p/f) on paragraphs of the VMS to see how many differences exist within the cipher's specification (max. 1 char added, max. 1 char removed): they could store between 5000 and 15000 characters of plaintext depending on how lines are reparsed (or not).

Everything Voynich is elusive. I suppose you'd do it the natural way: Create sequences of word differences according to various methods and then examine their statistical properties.
RE: Delta Cipher

oshfdk > 16-02-2026, 12:41 AM

(15-02-2026, 11:31 PM)Fontanellean Wrote: You are not allowed to view links. Register or Login to view.Everything Voynich is elusive. I suppose you'd do it the natural way: Create sequences of word differences according to various methods and then examine their statistical properties.

This assumes we know something about the plaintext. We are not even sure if it's Latin, Bavarian, Hebrew, or something even more exotic. It can be argued that for a normal medieval European made MS the most natural choice would be Latin, but the Voynich manuscript is certainly not a "normal" medieval MS, so very hard to guess the language.

Edit: I realized that I'm not sure I understood correctly what you were suggesting, could you elaborate?
Next Oldest Next Newest

Delta Cipher

Index

Delta Cipher

RE: Delta Cipher

RE: Delta Cipher

RE: Delta Cipher

RE: Delta Cipher

RE: Delta Cipher

RE: Delta Cipher

RE: Delta Cipher

RE: Delta Cipher

RE: Delta Cipher