Morteza Kashi
A C++ program analyzing a Vignere cipher knowing that 7 alphabets were used to encipher the plaintext. These programs decrypt an encrypted plain text
Here, we want to decrypt an encrypted plaintext. This plain text has been encrypted according to a Vignere cipher. We also know that this Vignere cipher has used 7 alphabets.
Please find the cipher text stored in Ciphere.txt file .
Procedure of Encryption:
As we know, 7 alphabets were used to encipher the plaintext. There fore we are looking for 7 keys. Having these 7 keys we can break the encryption by a C++ program.
We divide the cipher text in many group of letters containing 7 alphabets in sequence. So each group is extracted from the cipher text in order and it contains 7 alphabets. We pick first alphabet of each group and put them all in a sub list T1.We do the same thing with the second alphabet in each group and make sub list T2.Since we have 7 alphabet in each group we can make 7 sub lists T1,T2,T3,...,T7 by the same way.
Therefore each sub text is a caesar cipher where its key is the ith letter of the Vignere keyword.
Finding all of these, we find out that the Vignere keyword is PICKLES which corresponds to the sries of numbers as: {15,8,2,10,11,4,18} in English alphabet.
Having this key, we can brak this cipher by the following C++ code:
The input of this program must be located on C drive by the name Cipher.txt .The out put of the program would be located on C drive in file called Plaintext.txt as it is designed in the program.
Please click on the following link, should you want to see the execution of the program. To do that, Save the file "Cipher.exe" on your desktop or somewhere else on your computer. Then, double click on it to see the execution of the program.
Please contact me by clicking HERE and filling out the coming simple form, should you have any question about this program.
