Singachea

Have you ever thought you want to create a language understood by the desired partner only? If so, it may be too late for you to think of it. Talking about ciphertext, I remembered what I had learn from a course of Introduction to Programming last semester. Still, I think it’s good if I share it to you guys here.

Some of you may anxiously question what ciphertext is; I have to say “relax! read the following abstract slowly.”

Ciphers are used to produce messages which can be understood only by the sender and authorized receivers, so ciphers can be used for secret correspondence in situations where the message may fall into the wrong hands. The process of converting a readable message (the plaintext) to an unreadable form (the ciphertext) is called “encryption”; converting ciphertext to plaintext is called “decryption”. The Vigenere cipher was developed by Biaise de Vigenere around 1586, for French diplomatic and military communications. The Vigenere cipher uses a keyword and a 26-by-26 matrix of letters to substitute plaintext letters with ciphertext letters, and vice versa. The message sender and receiver must both use the same matrix and keyword. For this experiment, the matrix will be:

The matrix contains the (uppercase) ciphertext letters. The lowercase letters are the row and column indices.

To encrypt a plaintext letter:

• *The plaintext letter is matched with a keyword letter, as shown below.
• *The keyword letter determines the ROW of the matrix. Find the row that begins with the keyword letter.
• *The plaintext letter determines the COLUMN of the matrix.
• *The ciphertext letter is found at the intersection of ROW and COLUMN

For example, if the keyword is “calculus” and the plaintext is “beammeupscotty”:

Keword: calculus
Plaintext: beammeupscotty

The ciphertext will be “DELOGPOHUCZVNJ”.

The first plaintext letter, ‘b’, is matched with the first keyword letter, ‘c’, so the first ciphertext letter, ‘D’, is found in the matrix at row ‘c’, column ‘b’. The second ciphertext letter, ‘E’, is found at row ‘a’, column ‘e’, etc.

To decrypt a message, the processs is reversed. The ciphertext is matched with the same keyword as was used in the encryption. As before, a keyword letter determines a row of the matrix. To decrypt a ciphertext letter:

• *Match the ciphertest letter to a keyword letter.
• *Search the row corresponding to the keyword letter, then locate the ciphertext letter.
• *Find the index of the column in which the ciphertext letter appears. The column index is the plaintext letter that corresponds to the given ciphertext letter.

How do think about this method? Even though it’s not so secured as the modern encryption method MD5, but I think it’s good enough for some who want to say love to their …

Actually, it’s not convenient to translate those letters by ourselves. If you really like this method, please drop me an email so that I upload the applet which is able to convert the message in a flash.