Caesar Cipher

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@giblit
The Caesar Cipher is for the alphabet.

Alphabet:
An alphabet is a standard set of letters (basic written symbols or graphemes) which is used to write one or more languages based on the general principle that the letters represent phonemes (basic significant sounds) of the spoken language.
but the others told me that Caesar Cipher can extend to numbers , it means it is for alphabets as a universal standard set of letters concerning all languages and it can accept numbers too is not it????
@BHXSpecter. It is any character in which the language is created. 1337 is a language that uses numbers , letters , and symbols to create the language. Also the Romans have I , V , X in their "alphabet" and they are used as letters and numbers.
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@giblit
Do you realize your argument is a little odd. Alphabet is the letters of a language, the numbers of a language are the numerals/numerical symbols of the language. Every language has both, but Caesar Cipher focuses on the letters of the languages and not the numbers.
> it means it is for alphabets as a universal standard set of letters
> concerning all languages and it can accept numbers too is not it????

Any message - either plaintext or ciphertext - is formed out of a set of specific symbols(an alphabet). Assertions that an alphabet is required (no matter how pompously made), merely overstate the obvious. Assertions that an alphabet is all that is required for a shift cipher miss the point altogether.

The specific requirement of a shift cipher is that the alphabet must be 'ordered'. (Duoas had pointed this out several posts ago; I'm repeating it because it seems to have gone completely unheeded).

So, this "universal standard set of letters concerning all languages and it can accept numbers too" can be used for a shift cipher if and only if an ordering is imposed on this universal set.

The "Caesar cipher" in its original form was restricted to the specific alphabet consisting of the 26 ordered symbols that Caesar used. In cryptography, the term "Caesar cipher" usually refers to any simple shift cipher.
because Caesar Cipher is a Shift Cipher it can accepts all characters and numbers without exceptions
In cryptography, the term "Caesar cipher" usually refers to any simple shift cipher.

Much like Kleenex is used in place of "facial tissue," I would imagine. Not (always) technically correct, but it definitely gets the meaning across.

http://www.factmonster.com/ipka/A0768920.html


because Caesar Cipher is a Shift Cipher it can accepts all characters and numbers without exceptions

No.
I can't read all the posts. It gives me a headache.

Cipher: method for performing encryption and/or decryption
http://en.wikipedia.org/wiki/Cipher

Key: information that determines output of cipher
http://en.wikipedia.org/wiki/Key_(cryptography)

Ceasar Cipher: a specific algorithm
Alphabet 'A' to 'Z': specific key unrelated to cipher but used by it

Your program would be the cipher which is limited by the key.
Okay, okay, I think we have a war of words going on here. The problem is that there are a couple valid, but different viewpoints, with the result that we think we're all having the same conversation but we aren't.

The Caesar Cipher is a method that, in Caesar's time, applied to Caesar's alphabet. Romans wrote everything -- including numbers -- with the letters of that alphabet. And it is unlikely Caesar sent messages with spaces conveniently placed in the right spots to help interceptors decode his messages -- especially as they were unnecessary anyway. (Spacing was an artifact coming from the need to make it easier for foreigners to read the Latin texts.)

These days, we Anglophiles (incorrectly) define Caesar Ciphers to only operate over the letters A-Z. That's all fine and well, if you want to live with the distinction.


Here's the problem: Encoding != Encrypting. (Yes, it is a fine line, but it is our problem.)

Technically, Caesar encoded his text. (In his day, it served, perhaps for some small time, as a useful encryption method, but I doubt that it took very long for his contemporaries to figure it out.)

Those of use who know something about modern cryptography have specific vocabularies, and all these terms are fairly overloaded.

As JLBorges wrote:
In cryptography, the term "Caesar cipher" usually refers to any simple shift cipher.

The important clause here is in cryptography.

Otherwise we are just playing with our decoder rings where the Caesar Cipher's alphabet is arbitrarily restricted to the English A-Z.

In basic CS courses, the A-Z only cipher is a favorite assignment because it requires the student to consider several things:

  - filtering text (some letters are modified and some are not)
  - transforming text (via a mathematical operation and some nice indexing)
  - a little discrete mathematics (modular arithmetic)

Now, when OP uses "encode" and "decrypt" in the same breath, it invites us to err in our responses. I read "decrypt" and automatically assumed he was studying cryptography. Closer thought (and OP's confusion on the subject) might have warned me that he is in a basic CS course.


Which leads to the next problem: OP was confused by the same. That was the point of his questioning. To paraphrase:

    "I found stuff on the web that claims to be a Caesar Cipher but
     doesn't conform to what I was taught nor to other stuff I found
     on the web. What gives?"

What gives is that, strictly speaking, in most contexts, a Caesar Cipher is an A-Z ring encoder/decoder method.

In cryptography, a Caesar Cipher is a specialization of a substitution cipher, and need not be limited to A-Z. (And technically, it is still not an encryption method, but it is useful for massaging data during an encryption process.)

So, whether or not you also shift numbers and spaces and punctuation with your letters is up to you (or whatever your professor wants).

Hope this helps.
In his day, it served, perhaps for some small time, as a useful encryption method, but I doubt that it took very long for his contemporaries to figure it out.


It took 800 years according to this: https://www.khanacademy.org/math/applied-math/cryptography/crypt/v/caesar-cipher

It was probably due to the fact many people were illiterate back then and only a handful of people ever found his messages.

*edit those videos are really entertaining thanks for link.
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There is that, lol

I got the link from a math teacher a while back and haven't seen most of them. Some day I hope get through all of them though.
giblit wrote:
It was probably due to the fact many people were illiterate back then and only a handful of people ever found his messages.

Makes you wonder if some of his unfound ones are actually family heirlooms now? After all, some families do have some unusual heirlooms.
> Makes you wonder if some of his unfound ones are actually family heirlooms now?

Does this kind of bilge have anything that is (even remotely) connected to programming or learning C++?
JLBorges wrote:
Does this kind of bilge have anything that is (even remotely) connected to programming or learning C++?

In a word? No. I'm a historically inclined person. There is always a historical significance if there are ciphers passed as heirlooms as it would give historians a deeper glimpse into Caesar's mind. My remark had no more connection to programming or learning C++ than admkrk's or giblit's previous replies above mine. Just like this thread has nothing to do with learning C++ or programming, it had to do with if the Caesar Cipher was just A-Z or could use numbers and symbols. Just as your post to point out it has no connection to programming or learning C++, unless you were hoping to start an argument.

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> My remark had no more connection to programming or learning C++ than
> admkrk's or giblit's previous replies above mine.

Your remark had nothing to do with programming at all.

The strength of a cipher - which incidentally does have quite a bit to do with programming - is what admkrk and giblit were discussing.

This is the programming section of a programming forum; you were trolling.


> unless you were hoping to start an argument.

No, I do not. For the record, I do not consider you worthy enough to hold an argument with.
JLBorges wrote:
The strength of a cipher - which incidentally does have quite a bit to do with programming - is what admkrk and giblit were discussing.

Strength of a cipher, yeah that is programming related if they were talking about it current. They are talking about how long it took them to break Caesar's Cipher during his time and shortly after, of which I don't consider that to be programming related at all, but rather history related.
JLBorges wrote:
No, I do not. For the record, I do not consider you worthy enough to hold an argument with.

Then you don't understand the definition of argument because that reply did just that. Presented an argument against my reply, we are discussing our different points of views in regards of how we interpret what they were discussing.
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