Codes and ciphers. The difference between them is that ciphers encode letter by letter, codes encode word by word.

I’ve been reading the excellent book Dunin and Schmeh “Codebreaking – a practical guide”, which put me in mind of two types of ciphers that I made up when I was a youth. Neither of them is in that book, I’m not sure whether to be surprised by this or not. On the one hand thousands of other people must have come up with my ciphers, and on the other hand there must be hundreds of thousands of types of ciphers.

I’d like to know what they are called.

The first I came up with is a simple way of flattening the frequency distribution of letters in a cipher.

In its simplest form, the plaintext aaaaaaaa becomes ciphertext bcdefghi.

Try this one uchyt cfqsl zwlqf dnivk etpum gotfg gfjyf

The second cipher was intended to be easier to solve by hand then by computer.

In it’s simplest form, the plaintext aaaaaaaaaaaaaaaaaaaa becomes zbzzbbzzbbzbzzbzbzbb using a random rise or fall.

For decoding, go up and down one from the ciphertext, giving
acaaccaaccacaacacacc
yayyaayyaayayyayayaa
And then by eye, thread a path up and down through the two lines of decoded text for a result with sensible words and grammar to get, in this case, aaaaaaaaaaaaaaaaaaaa.

Try this one, the plaintext is a quote from the uncyclopedia xppjh fdtbq flpru eznpt tgnqs ifjql fbuvi hbijr bszod ngfbt sfqoj mehzo cfmjb zbxdz ufoot sdmxc zftmw dht

It’s generally true that the more options there are for the “key”, the more difficult it is to solve a cipher. For a caesar cipher (a constant number added to each letter), the key is between 1 and 25. For a simple substitution cipher, the key is between 1 and ~325. The two ciphers above have no key, or to be more specific the key is 1. That makes them even easier to solve than a caesar cipher.

For serious coding puposes to hide content, we add a long key to make it more difficult to crack.

So, what I’m asking is:
a) What is the name of a cipher that is designed to use earlier encoded material to decript the latest encoded letter?
b) What is the name of a cipher that is designed to have multiple decriptions into plaintext, with an ambiguity that is only resolved by use of a dictionary?

autokey

degenerate

end

mollwollfumble said:

Codes and ciphers. The difference between them is that ciphers encode letter by letter, codes encode word by word.

Huh? I don’t think this is accurate.

Morse Code ‘encodes’ letter by letter, not word by word, for example.

semantic siphons

https://crypto.interactive-maths.com/other-examples1.html

One of the most famous examples of a cipher in regular use is Morse Code (which is not a code, but rather a cipher). Morse Code has the benefit that it can be transmitted in several ways,

SCIENCE said:

semantic siphons

https://crypto.interactive-maths.com/other-examples1.html

One of the most famous examples of a cipher in regular use is Morse Code (which is not a code, but rather a cipher). Morse Code has the benefit that it can be transmitted in several ways,

Used to be able to do 8 w.p.m. in Morse by sound or light. 10 w.p.m. if both brain cells were functioning that day.

wonder how i’d go now?

Might have to give these recordings a try:

https://fourble.co.uk/podcast/usarmedforcesinstitutebasicradiocode1942ulbyaf2z

https://www.brynmawr.edu/bulletin/codes-and-ciphers-puts-students-test

Codes substitute arbitrary symbols—typically, letters or numbers—for the components of the original message. Ciphers use algorithms to transform a message into an apparently random string of characters.

ChrispenEvan said:

https://www.brynmawr.edu/bulletin/codes-and-ciphers-puts-students-test

Codes substitute arbitrary symbols—typically, letters or numbers—for the components of the original message. Ciphers use algorithms to transform a message into an apparently random string of characters.

next you’ll be telling us that language is code

SCIENCE said:

ChrispenEvan said:

https://www.brynmawr.edu/bulletin/codes-and-ciphers-puts-students-test

Codes substitute arbitrary symbols—typically, letters or numbers—for the components of the original message. Ciphers use algorithms to transform a message into an apparently random string of characters.

next you’ll be telling us that language is code

No I won’t. But it is.

If letters and words can be encoded what about sentences and paragraphs?

Tau.Neutrino said:

If letters and words can be encoded what about sentences and paragraphs?

As a whole ?

Cymek said:

Tau.Neutrino said:

If letters and words can be encoded what about sentences and paragraphs?

As a whole ?

Y.

Tau.Neutrino said:

If letters and words can be encoded what about sentences and paragraphs?

It’s even possible to encode an entire book into a single symbol.

btm said:

Tau.Neutrino said:

If letters and words can be encoded what about sentences and paragraphs?

It’s even possible to encode an entire book into a single symbol.

¡ in fact, imagine the fun one could have if one were able to encode in a symbol, a reference to that symbol itself, it would be Göd-like !

SCIENCE said:

btm said:

Tau.Neutrino said:

If letters and words can be encoded what about sentences and paragraphs?

It’s even possible to encode an entire book into a single symbol.

¡ in fact, imagine the fun one could have if one were able to encode in a symbol, a reference to that symbol itself, it would be Göd-like !

Or even the negation of that symbol.

mollwollfumble said:

Try this one uchyt cfqsl zwlqf dnivk etpum gotfg gfjyf

Try this one, the plaintext is a quote from the uncyclopedia xppjh fdtbq flpru eznpt tgnqs ifjql fbuvi hbijr bszod ngfbt sfqoj mehzo cfmjb zbxdz ufoot sdmxc zftmw dht

Did you get those?

The first decrypts as the quick brown fox jumpos over the lazy dog

The second decrypts as Wookiees are most famous for their meat, which is a type of Eastern Indian delicacy eaten purely by eunuchs.

Hto hwean bnooustupbe srtmiut tuat, ti ioonnsciinpvh oelrvsed.

SCIENCE said:

Hto hwean bnooustupbe srtmiut tuat, ti ioonnsciinpvh oelrvsed.

autokey

degenerate

end

“An autokey cipher (also known as the autoclave cipher) is a cipher that incorporates the message (the plaintext) into the key.”

Close, but this incorporates the message (the ciphertext) into the key rather than the plaintext. The purpose is to flatten the letter frequency distribution because the ciphertext is close to random whereas the plaintext is not.

Encoding a longer message using just the sum of current plaintext letter and previous ciphertext message gave me this letter frequency distribution.

Plaintext. e=5 is the most common letter.

Ciphertext

Random letters

> degenerate cipher

Would be a case of a single cipher splitting into multiple independent ciphers. So is similar to what I have. But applied differently as a degenerate cipher would tend to have a repeat length wouldn’t it, whereas what i’m proposing wouldn’t have a repeat length.

> Hto hwean bnooustupbe srtmiut tuat, ti ioonnsciinpvh oelrvsed.

Not either of my ciphers, that’s for sure. Too many instances of the letter ‘t’.

> end

:-)