George owns a company that produces mobile phones to end users. George’s company

Question

George owns a company that produces mobile phones to end users. George’s company must keep up with other competitors therefore during a company meeting George announced that he will be making changes to their new upcoming mobile device. George’s company follows a strict confidentiality policy when it comes to the exchange of information. To prevent the leakage of information during transmission George also informed his employees during the meeting that he will be sending them instructions encrypted under Caesar cipher followed by another substitution where the key is 234. Employees received the following cipher text. NTJWKHXK AMK WWUJJYZTX MWKXZKUHE What is the plain text?

i have seen all the given answer still i am posting this question to get more effective answer with 800 words and step by step solution with plain text please.

Explanation / Answer

Answer)

Before conversion of the cipher text given to plain text.

Let us understand what Cipher text is:

Cipher is an algorithm which allows the plain text to be encrypted to ciphertext.

A cipher text is not readable unless it is converted to plain text using a key.

The key can be divided into 2 types:

Private-key Cryptography: where the key is shared between the sender and receiver which is kept secret from all other parties.This key will be used for both encryption and decryption. DES and AES are examples of this kind of cipher.

Public-key Cryptography: We have 2 types of key here the private and the public key. The sender uses the public key to encrypt where as the receiver is not made aware of the private key. This kind of algorithm used is called as Asymmetric key Algorithm.

ROT13 key other wise referred as rotate by 13 places is a special case of cipher used to replace a letter with 13th letter after it.

Note: The key 13 used is the ROT13 (rotate by 13 places) key which is used to replace a letter with the 13th letter after it.

Before we move to the steps lets concentrate on the numbering of the letters in Latin Language.

A=1, B=2, C=3, D=4, E=5, F=6, G=7, H=8, I=9, J=10, K=11, L=12, M=13, N=14, O=15, P=16, Q=17, R=18, S=19, T=20, U=21, V=22, W=23, X=24, Y=25, Z=26.

Using the ROT13 the Encrypted form of letter A will be N because A being in 1 position the 13th letter following it would be N which is at the 14th position.

A=1 , so ROT13 will be 1+13=14 (The 14th place has N) hence the Plain text for letter A will be N.

B=2, so ROT13 will be 2+13=15 (The 15th place has O) hence the plain text for the letter B will be O and so on.

For the Cipher text:

NTJWKHXK AMK WWUJJYZTX MWKXZKUHE

The plain text will be:

AGWJXUKX NZX JJHWWLMGK ZJXKMXHUR

Steps:

1) N being at 14th position and when Key 13 is used then

N being 14 , so 14+13 = 27 (26 being the Z alphabet hence A will take the place of 27th position).

The plain text for N will be A

2) T being at 20th position and when Key 13 is used then

T being 20 , so 20+13 = 33 (26th position being the Z alphabet hence 33-26=7 so 7 positions ahead of the letter Z that will be G).

The plain text for T will be G and so on.

We will always have 26 number into consideration as we have a maximum of 26 alphabets in English Language.

And the half that is 13 will be used for rotating the string as a result of which Key 13 is being considered.

Hope this answer satisfies.

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