White Hat Institute

“Defend the Web” write-up (Crypt 2 / Crypt)

“Defend the Web” write-up (Crypt 2 / Crypt — cracking Caesar cipher encryption)

A Caesar cipher, also known as Caesar’s cipher, the shift cipher, Caesar’s code, or Caesar shift in cryptography, is one of the most basic and well-known encryption schemes. It’s a substitution cipher in which each letter in the plaintext is replaced by a letter that’s a certain number of positions down the alphabet. With a left shift of 3, for example, D would become A, E would become B, and so on. Julius Caesar is credited with inventing the approach, which he utilized in his private communication.

In this challenge, the cipher is already given. All you need to do is to crack it by using any available online craking platform. 

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Copy the text and open a Google search engine. Search for “Caesar Cipher decoder” and click on the first available one.

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Paste the text in the decoder field and click on the “Decrypt Caesar code” button.

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Copy the password and use it on the login page to access it and pass the challenge.

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If you’re using English, you might only have 26 options to choose from. You begin with the following alphabet: ABCDEFGHIJKLMNOPQRSTUVWXYZ.

Then you shift it, say three spaces to the right of your starting point. You’ll end up with something like this: defghijklmnopqrstuvwxyzabc.

As a result, you change A to D, B to E, and so on. Using a shift value of 3, we get “khoor” as the cipher-text with “hello” as plain-text. Simply move each letter from the ciphertext three spaces to the left to restore the plain text. What if you see the word “lttigd”? This is nonsense, therefore let’s move everything to the left till it makes sense. We get “ksshfc,” “jrrgeb,” “iqqfda,” “hppecz,” and “goodby.” The plain text appears to be “goodbye.”

With the system we’re utilizing, the worst-case situation is that you’ll require 26 trials. Even without the use of a computer, this can be accomplished very easily, and with a computer, it becomes straightforward.