1.) Write a function that will take in two strings and encrypt the first string with the second string using the Vigenere ciphere. The first string is the plaintext and your function should ignore all non-alphabetic characters (or your code can remove them from the string). All uppercase letters should be treated as lowercase letters (or you can convert the string to all lowercase letters). The second string is the key and it should be able to be from 1 character long to even longer than the plaintext string itself.
Then write a function that, given two strings, decrypts the first string using the second string. Same conditions should apply as before.
Once these functions are completed, have your main body prompt the user for a string to encode, then a key string, then perform the encryption of the plaintext and output the ciphertest.. Then decrypt it and show the resulting plaintext.
2.) Now we are wanting to automate the process of decrypting a string using the vignere ciphere.
In the main body, prompt the user for a ciphertext string encoded by the vignere cipher with an unknown key. Then prompt the user for a substring that we know has to be in the plaintext and a maximum size of the key (from 1 to 10 let us say). Your code should then brute-force the vignere cipher by decrypting the text using a possible key and then examining the possible plaintext for the substring. If the substring is in the possible plaintext, your code should print it out as a possible result, along with the key found, and then prompt the user if they would like to continue. You should also stop at every increment of keysize and ask them if they wish to continue the brute force.
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Dear Client! I'm really interested in your project. I have good c/c++ coding skills. I have also a deep knowledge for Cryptography . I can help you. Lets discuss more detail in private chat. Thanks
Hello Greetings I have read your project description and has experience working on Vigenere Cipher. I can complete this project within a day. Please revert ac to discss the details. Regards Sangeeta