Ciphers and Codes

I am greatly honored that you enjoyed my last post (Frgh Brxu Olih), that was an introduction to cryptography. Since the subject is of interest, I decided to give it more space. So, today I will speak a little more about ciphers and codes.

The word "Cipher" means zero and its origin is "Sifr" or "صفر" which is an Arabic numeral that also is the origin of the Latin "0" (Please refer to "Wonders of Numbers" post). However, "Code" came from the Latin word "Codex".

The difference between a cipher and a code is a bit blurry. In general both terms are used as equal, but there is a very small technical difference that I will try to make simple for you:

First, a cipher works on the level of letters to be substituted by another letter, number or symbol. So, by that you transform your "Plaintext" into "Ciphertext" that can only be read through a key. Of course, without that key no one can decode this message. What I have presented in the last post is a form of "Ciphering".

Secondly, a code is to substitute a meaning of the whole word for another word, symbol or a sentence. Codes are decoded also according to a known key or codebook. "Morse Code" is a famous example of encoding.

In the middle of any crisis, you will find primitive coding techniques as "Morse Code" rising to the front raw. A very recent example is what happened in the period of communication cut-off in the Egyptian revolution in early January. The only way the activists manage to send their messages to each other and to the world was through the "Ham Radio". Through this simple radio some activists send messages using Morse code.

Morse code is very simple to learn, the code is constituted of dots "vocalized dit" and dashes "vocalized dah" (see the diagram). The dot when it is not at the end it is vocalized "di". The space between 2 letters equals 3 dots and the space between 2 words is five dots (currently 7 dots between words).

So for example the letter "L" will be read "di-dah-di-dit" and the letter "C" will be "dah-di-dah-dit" and so on.

Another example: can you decode this?

●●●----- ▬ ▬ ▬------ ●●●

To read the answer below please press and hold left click at the end of this sentence and sweep it down.

"SOS" which is an international HELP ME code, it stands for "Save Our Lives".

I guess the fiction writers were right. When they write about a major disaster they always point out that nothing will be working and people will have to use old techniques. The Egyptian revolution proved that right. However, I can't deny that the more technological cryptographies are easier and more fun to learn. Using computer software to encrypt a message is indeed very difficult to decode and is thus very safe and secure. These new technologies are the methods we use in our everyday life in ATM, passwords and others.

If you want to read something about ancient cryptographies, there are many books written over the subject. Also there are many websites and books about the more modern techniques as well.

Back to Morse code, can you decode this?

▬ ●●●-------▬ ●▬ ▬------●----------------●●▬●-------▬ ▬ ▬--------● ▬ ●----------------▬ ●--------▬ ▬ ▬--------● ▬ ▬

To read the answer please press and hold left click at the end of this sentence and sweep it down.

Bye for now

Now, I leave with this code:

▬ ▬ ▬-------●●● ▬--------●--------●▬● --------------- ● ▬--------▬●--------▬●● ----------------▬ ▬ ▬--------●● ▬--------▬

Image credit by Thomas H. White via Wikimedia Commons