Is there a cipher related to colors and letters?

Question

I was just wondering if a cipher existed where a number of symbols were colored with different colors forming a cipher?

Answer 1

Something that may interest you would be a secret sharing scheme by Shamir titled Visual Cryptography.

http://www.cs.nccu.edu.tw/~raylin/UndergraduateCourse/ComtenporaryCryptography/Spring2009/VisualCrypto.pdf

Answer 2

I haven't seen any such implementation of a cipher. That being said, you could implement it yourself. If you take each byte in a cyphertext and put them into a bitmap, you can display each "letter" as a pixel. Remember, a byte consists of 8 bits, which can represent a number between 0 and 255. Which is one of the most common amount of colors a pixel can hold.

Answer 3

I was just wondering if a cipher existed where a number of symbols were colored with different colors forming a cipher?

What you describe is not related to cryptography, but practically boils down to a form of encoding a ciphertext.

Cryptographically secure ciphers tend to programmatically output a series of bytes. How you handle and represent those bytes is up to you. Most of the time you'll see binary blobs (read: data packages like files) or - for example when using GnuPG/PGP in emails - somewhat long HEX strings.

So, to answer your question directly: since "encoding" is something completely different than "encryption" and since "encoding" does not add any security, you will not find any cryptographically secure cipher which natively produces an output "where a number of symbols were colored with different colors forming a cipher".

At its best, yet totally insecure for cryptographic use, your idea would result in a kind of (monoalphabetic) substitution cipher; also known as pigpen cipher.

By the way…

Related to your question, you might also want to check on the Q&A "Are specially designed fonts sometimes used in cryptography?" as it comes pretty close to what you are thinking about. To keep this answer short, I'll simply refrain from repeating the same infos which I already provided in my answer there.